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Trinseo (TSE)

Document and Entity Information

Document and Entity Information - shares9 Months Ended
Sep. 30, 2021Nov. 04, 2021
Cover [Abstract]
Document Type10-Q
Document Quarterly Reporttrue
Document Period End DateSep. 30,
2021
Document Transition Reportfalse
Entity File Number001-36473
Entity Registrant NameTrinseo PLC
Entity Incorporation, State or Country CodeL2
Entity Tax Identification Number00-0000000
Entity Address, Address Line One1000 Chesterbrook Boulevard
Entity Address, Address Line TwoSuite 300
Entity Address, Address Line ThreeBerwyn
Entity Address, City or TownBerwyn, PA 19312
Entity Address, State or ProvincePA
Entity Address, Postal Zip Code19312
City Area Code610
Local Phone Number240-3200
Title of 12(b) SecurityOrdinary Shares, par value $0.01 per share
Trading SymbolTSE
Security Exchange NameNYSE
Entity Current Reporting StatusYes
Entity Interactive Data CurrentYes
Entity Filer CategoryLarge Accelerated Filer
Entity Small Businessfalse
Entity Emerging Growth Companyfalse
Entity Shell Companyfalse
Entity Common Stock, Shares Outstanding38,837,083
Document Fiscal Year Focus2021
Document Fiscal Period FocusQ3
Entity Central Index Key0001519061
Current Fiscal Year End Date--12-31
Amendment Flagfalse

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in MillionsSep. 30, 2021Dec. 31, 2020
Current assets
Cash and cash equivalents $ 207.5 $ 588.7
Accounts receivable, net of allowance for doubtful accounts (September 30, 2021: $3.8; December 31, 2020: $5.6)762.7 469.5
Inventories617.3 324.1
Other current assets40 14.5
Current assets held for sale379.5 120.3
Total current assets2,007 1,517.1
Investments in unconsolidated affiliates250.3 240.1
Property, plant and equipment, net of accumulated depreciation (September 30, 2021: $560.6; December 31, 2020: $524.7)717 431.1
Other assets
Goodwill719.9 62.1
Other intangible assets, net841.2 162.6
Right of use assets - operating, net78.5 77.8
Deferred income tax assets84.9 90.2
Deferred charges and other assets65.3 36
Noncurrent assets held for sale228.2
Total other assets1,789.8 656.9
Total assets4,764.1 2,845.2
Current liabilities
Short-term borrowings and current portion of long-term debt149.1 12.2
Accounts payable507.9 325.9
Current lease liabilities - operating17.9 15.5
Income taxes payable32.3 10
Accrued expenses and other current liabilities216.6 127.5
Current liabilities held for sale81.3 42.2
Total current liabilities1,005.1 533.3
Noncurrent liabilities
Long-term debt, net of unamortized deferred financing fees2,307.9 1,158.1
Noncurrent lease liabilities - operating62.9 65.5
Deferred income tax liabilities100.5 60.7
Other noncurrent obligations365.7 395
Noncurrent liabilities held for sale42.3
Total noncurrent liabilities2,837 1,721.6
Shareholders' equity
Ordinary shares, $0.01 nominal value, 4,000.0 shares authorized (September 30, 2021: 48.8 shares issued and 38.8 shares outstanding; December 31, 2020: 48.8 shares issued and 38.4 shares outstanding)0.5 0.5
Additional paid-in-capital582.2 579.6
Treasury shares, at cost (September 30, 2021: 10.0 shares; December 31, 2020: 10.4 shares)(524.8)(542.9)
Retained earnings1,036.4 739.2
Accumulated other comprehensive loss(172.3)(186.1)
Total shareholders' equity922 590.3
Total liabilities and shareholders' equity $ 4,764.1 $ 2,845.2

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in MillionsSep. 30, 2021Dec. 31, 2020
Condensed Consolidated Balance Sheets
Allowance for doubtful accounts $ 3.8 $ 5.6
Accumulated depreciation $ 560.6 $ 524.7
Ordinary shares, nominal value $ 0.01 $ 0.01
Ordinary shares, shares authorized4,000,000,000 4,000,000,000
Ordinary shares, shares issued48,800,000 48,800,000
Ordinary shares, shares outstanding38,800,000 38,400,000
Treasury stock, shares10,000,000 10,400,000

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Condensed Consolidated Statements of Operations
Net sales $ 1,269.3 $ 679.2 $ 3,529 $ 1,976.5
Cost of sales1,101 572.9 2,951.7 1,789.1
Gross profit168.3 106.3 577.3 187.4
Selling, general and administrative expenses76.4 46.3 230.4 171.8
Equity in earnings of unconsolidated affiliates17.1 18.3 70.2 42.5
Impairment charges1.2 3 10.3
Operating income107.8 78.3 414.1 47.8
Interest expense, net23 10 56.6 32
Acquisition purchase price hedge loss22
Other expense (income), net(0.1)1.2 8.4 3
Income from continuing operations before income taxes84.9 67.1 327.1 12.8
Provision for income taxes5.5 26.9 48.9 16.2
Net income (loss) from continuing operations79.4 40.2 278.2 (3.4)
Net income (loss) from discontinued operations, net of income taxes13.7 65.6 38 (55.4)
Net income (loss) $ 93.1 $ 105.8 $ 316.2 $ (58.8)
Earnings Per Share
Weighted average shares- basic38.8 38.3 38.7 38.4
Net income (loss) per share- basic, continuing $ 2.04 $ 1.05 $ 7.19 $ (0.09)
Net income (loss) per share- basic, discontinued operations0.351.720.98(1.44)
Net income (loss) per share- basic $ 2.39 $ 2.77 $ 8.17 $ (1.53)
Weighted average shares- diluted39.5 38.4 39.6 38.4
Net income (loss) per share- diluted, continuing $ 2.01 $ 1.04 $ 7.03 $ (0.09)
Net income (loss) per share- diluted, discontinued operations0.351.710.96(1.44)
Net income (loss) per share- diluted $ 2.36 $ 2.75 $ 7.99 $ (1.53)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Condensed Consolidated Statements of Comprehensive Income (Loss)
Net income $ 93.1 $ 105.8 $ 316.2 $ (58.8)
Other comprehensive income (loss), net of tax
Cumulative translation adjustments(1.7)(6.7)(2)2.9
Net gain (loss) on cash flow hedges1.2 0.4 5.6 (4.6)
Pension and other postretirement benefit plans:
Net gain arising during period (net of tax of $1.0, $0.0, $1.0 and $0.1)9.3 0.1 9.3 0.7
Amounts reclassified from accumulated other comprehensive income(1.2)1.6 0.9 2.7
Total other comprehensive income (loss), net of tax7.6 (4.6)13.8 1.7
Comprehensive income (loss) $ 100.7 $ 101.2 $ 330 $ (57.1)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Condensed Consolidated Statements of Comprehensive Income (Loss)
Net gain (loss) during period, tax (benefit) expense $ 1 $ 0 $ (1) $ (0.1)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in MillionsOrdinary SharesTreasury SharesAdditional Paid-In Capital [Member]Accumulated Other Comprehensive Income (Loss) [Member]Retained EarningsTotal
Balance at beginning of period at Dec. 31, 2019 $ 0.5 $ (524.9) $ 574.7 $ (162.4) $ 781 $ 668.9
Balance at beginning of period, shares at Dec. 31, 201939 9.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income(36.3)(36.3)
Other comprehensive income (loss)8.2 8.2
Share-based compensation $ 1.7 1 2.7
Purchase of treasury shares $ (25)(25)
Purchase of treasury shares, shares(0.8)0.8
Dividends on ordinary shares(15.5)(15.5)
Balance at end of period at Mar. 31, 2020 $ 0.5 $ (548.2)575.7 (154.2)729.2 603
Balance at end of period, shares at Mar. 31, 202038.2 10.6
Balance at beginning of period at Dec. 31, 2019 $ 0.5 $ (524.9)574.7 (162.4)781 668.9
Balance at beginning of period, shares at Dec. 31, 201939 9.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income(58.8)
Other comprehensive income (loss)1.7
Balance at end of period at Sep. 30, 2020 $ 0.5 $ (546.5)578.7 (160.7)675.6 547.6
Balance at end of period, shares at Sep. 30, 202038.3 10.5
Balance at beginning of period at Mar. 31, 2020 $ 0.5 $ (548.2)575.7 (154.2)729.2 603
Balance at beginning of period, shares at Mar. 31, 202038.2 10.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income(128.4)(128.4)
Other comprehensive income (loss)(1.9)(1.9)
Share-based compensation $ 0.9 0.6 1.5
Share-based compensation, shares0.1 (0.1)
Dividends on ordinary shares(15.4)(15.4)
Balance at end of period at Jun. 30, 2020 $ 0.5 $ (547.3)576.3 (156.1)585.4 458.8
Balance at end of period, shares at Jun. 30, 202038.3 10.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income105.8 105.8
Other comprehensive income (loss)(4.6)(4.6)
Share-based compensation $ 0.8 2.4 3.2
Dividends on ordinary shares(15.6)(15.6)
Balance at end of period at Sep. 30, 2020 $ 0.5 $ (546.5)578.7 (160.7)675.6 547.6
Balance at end of period, shares at Sep. 30, 202038.3 10.5
Balance at beginning of period at Dec. 31, 2020 $ 0.5 $ (542.9)579.6 (186.1)739.2 $ 590.3
Balance at beginning of period, shares at Dec. 31, 202038.4 10.4 38.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income71.5 $ 71.5
Other comprehensive income (loss)6.1 6.1
Share-based compensation $ 12.9 (1.1)11.8
Share-based compensation, shares0.3 (0.3)
Dividends on ordinary shares(3.4)(3.4)
Balance at end of period at Mar. 31, 2021 $ 0.5 $ (530)578.5 (180)807.3 676.3
Balance at end of period, shares at Mar. 31, 202138.7 10.1
Balance at beginning of period at Dec. 31, 2020 $ 0.5 $ (542.9)579.6 (186.1)739.2 $ 590.3
Balance at beginning of period, shares at Dec. 31, 202038.4 10.4 38.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income $ 316.2
Other comprehensive income (loss)13.8
Balance at end of period at Sep. 30, 2021 $ 0.5 $ (524.8)582.2 (172.3)1,036.4 $ 922
Balance at end of period, shares at Sep. 30, 202138.8 10 38.8
Balance at beginning of period at Mar. 31, 2021 $ 0.5 $ (530)578.5 (180)807.3 $ 676.3
Balance at beginning of period, shares at Mar. 31, 202138.7 10.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income151.6 151.6
Other comprehensive income (loss)0.1 0.1
Share-based compensation $ 4.7 0.2 4.9
Share-based compensation, shares0.1 (0.1)
Dividends on ordinary shares(3.1)(3.1)
Balance at end of period at Jun. 30, 2021 $ 0.5 $ (525.3)578.7 (179.9)955.8 829.8
Balance at end of period, shares at Jun. 30, 202138.8 10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income93.1 93.1
Other comprehensive income (loss)7.6 7.6
Share-based compensation $ 0.5 3.5 4
Dividends on ordinary shares(12.5)(12.5)
Balance at end of period at Sep. 30, 2021 $ 0.5 $ (524.8) $ 582.2 $ (172.3) $ 1,036.4 $ 922
Balance at end of period, shares at Sep. 30, 202138.8 10 38.8

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Shareholders' Equity (Parenthetical)) - $ / shares3 Months Ended
Sep. 30, 2021Jun. 30, 2021Mar. 31, 2021Sep. 30, 2020Jun. 30, 2020Mar. 31, 2020
Condensed Consolidated Statement of Stockholders' Equity
Dividends on ordinary shares $ 0.32 $ 0.08 $ 0.08 $ 0.40 $ 0.40 $ 0.40

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions9 Months Ended
Sep. 30, 2021Sep. 30, 2020
Cash flows from operating activities
Net income (loss) $ 316.2 $ (58.8)
Net income (loss) from discontinued operations38 (55.4)
Net income (loss) from continuing operations278.2 (3.4)
Adjustments to reconcile net income (loss) from continuing operations to net cash provided by (used in) operating activities - continuing operations
Depreciation and amortization111 69.8
Amortization of deferred financing fees, issuance discount, and excluded component of hedging instruments5.5 2.8
Deferred income tax0.2 (0.3)
Share-based compensation expense11 8.7
Earnings of unconsolidated affiliates, net of dividends(10.2)(42.5)
Unrealized net gain on foreign exchange forward contracts(25.2)(9.8)
Acquisition purchase price hedge loss22
Pension curtailment and settlement (gain) loss(2.1)1
Asset impairment charges or write-offs3 10.3
Changes in assets and liabilities
Accounts receivable(253.1)23.5
Inventories(196.7)107.3
Accounts payable and other current liabilities249.5 (51.2)
Income taxes payable22.3 2.1
Other assets, net(9)(15.8)
Other liabilities, net41 (11.3)
Cash provided by operating activities, continuing operations247.4 91.2
Cash provided by (used in) operating activities, discontinued operations(9.2)36.5
Cash provided by operating activities238.2 127.7
Cash flows from investing activities
Capital expenditures(64.7)(47.4)
Cash received (paid) for asset and business acquisitions, net of cash acquired ($12.1 and $0)(1,806.6)0.1
Proceeds from the sale of businesses and other assets0.2 11.9
Proceeds from (payments for) the settlement of hedging instruments(14.7)51.6
Cash provided by (used in) investing activities, continuing operations(1,885.8)16.2
Cash used in investing activities, discontinued operations(3.3)(13.5)
Cash provided by (used in) investing activities(1,889.1)2.7
Cash flows from financing activities
Deferred financing fees(35)
Short-term borrowings, net(11.6)(8.2)
Purchase of treasury shares(25)
Dividends paid(9.5)(46.5)
Proceeds from exercise of option awards10.5 0.4
Withholding taxes paid on restricted share units(0.8)(0.6)
Net proceeds from issuance of Term Loan B746.3
Repayments of Term Loans(7.1)(5.2)
Net proceeds from issuance of Senior Notes450
Proceeds from draw on 2022 Revolving Facility100
Repayments of Revolving Facility(100)
Proceeds from draw on Accounts Receivable Securitization Facility150
Repayments of Accounts Receivable Securitization Facility(20)
Cash provided by (used in) financing activities1,272.8 (85.1)
Effect of exchange rates on cash(3.1)1.3
Net change in cash, cash equivalents and restricted cash(381.2)46.6
Cash, cash equivalents and restricted cash, beginning of period588.7 457.4
Cash, cash equivalents and restricted cash, end of period207.5 504
Restricted cash(0.7)
Cash and cash equivalents, end of period207.5 503.3
Supplemental disclosure of cash flow information
Net cash received $ 12.1 $ 0

Basis of Presentation

Basis of Presentation9 Months Ended
Sep. 30, 2021
Basis of Presentation
Basis of PresentationNOTE 1—BASIS OF PRESENTATION The unaudited interim condensed consolidated financial statements of Trinseo PLC and its subsidiaries (the “Company”) as of and for the periods ended September 30, 2021 and 2020 were prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and reflect all adjustments, consisting only of normal recurring adjustments, which, in the opinion of management, are considered necessary for the fair statement of the results for the periods presented. Because they cover interim periods, the statements and related notes to the financial statements do not include all disclosures normally provided in annual financial statements, and therefore, these statements should be read in conjunction with the 2020 audited consolidated financial statements included within the Company’s Annual Report on Form 10-K (“Annual Report”) filed with the Securities and Exchange Commission (“SEC”) on February 22, 2021. The Company’s condensed consolidated financial statements presented herein reflect the latest estimates and assumptions made by management that affect the reported amounts and related disclosures as of and for the period ended September 30, 2021. However, actual results could differ from these estimates and assumptions. On October 8, 2021, the Company completed a cross-border merger transaction, pursuant to which its former publicly-traded parent entity, Trinseo S.A., a Luxembourg limited liability company, was merged with and into Trinseo PLC, an Irish public limited company, with Trinseo PLC as the surviving entity (the “Redomiciliation”). The Redomiciliation was completed pursuant to an agreement between the parties entitled the Common Draft Terms of Merger dated as of April 23, 2021 and was approved by shareholders at Trinseo S.A.’s 2021 annual general meeting on June 14, 2021. As a result of the Redomiciliation, all of Trinseo S.A.’s outstanding ordinary shares, par value $0.01 per share, excluding treasury shares, were exchanged on a one-for-one basis for newly issued ordinary shares, par value $0.01 per share, of Trinseo PLC. The treasury shares of Trinseo S.A. were cancelled in conjunction with the Redomiciliation. All references herein to “Trinseo” or the “Company” refer to Trinseo S.A. and its subsidiaries through the effective date of the Redomiciliation, and thereafter refer to Trinseo PLC and its subsidiaries. As the Redomiciliation was completed subsequent to September 30, 2021, amounts presented herein represent the results of Trinseo S.A. as of and for the periods ended September 30, 2021 and have not been adjusted for the equity transactions completed in connection with the Redomiciliation on October 8, 2021. The December 31, 2020 condensed consolidated balance sheet data presented herein was derived from the Company’s December 31, 2020 audited consolidated financial statements, but does not include all disclosures required by GAAP for annual periods. Certain prior year amounts have been reclassified to conform to the current year presentation. These reclassifications pertain primarily to the Company’s entry into an agreement during the second quarter of 2021 to sell its Synthetic Rubber business, as a result of which the Company reclassified its Synthetic Rubber assets and liabilities as held-for-sale and reclassified the operating results of its Synthetic Rubber business, net of taxes, as discontinued operations for all periods presented. Refer to Note 4 for further information. Throughout this Quarterly Report, unless otherwise indicated, amounts and activity are presented on a continuing operations basis. Additionally, the condensed consolidated financial statements herein reflect reclassifications related to the Company’s resegmentation effective October 1, 2020, as described in Note 16.

Recent Accounting Guidance

Recent Accounting Guidance9 Months Ended
Sep. 30, 2021
Recent Accounting Guidance
Recent Accounting GuidanceNOTE 2—RECENT ACCOUNTING GUIDANCE In December 2019, the FASB issued guidance that simplifies the accounting for income taxes. The amended guidance includes removal of certain exceptions to the general principles of Accounting Standards Codification (“ASC”) 740, Income Taxes, and simplification in several other areas such as accounting for a franchise tax (or similar tax) that is partially based on income. The Company adopted the guidance effective January 1, 2021, noting that adoption did not have a material impact on its consolidated financial statements.

Acquisitions

Acquisitions9 Months Ended
Sep. 30, 2021
Acquisitions
AcquisitionsNOTE 3—ACQUISITIONS Acquisition of Aristech Surfaces On September 1, 2021, the Company completed its previously announced acquisition of Aristech Surfaces LLC (“Aristech Surfaces”) from SK AA Holdings LLC (“SK AA Holdings”), the sole member of Aristech Surfaces, through purchase of 100% membership interest and intellectual property (the “Aristech Surfaces Acquisition”). Aristech Surfaces is a leading North America manufacturer and global provider of PMMA continuous cast and solid surface sheets, serving the wellness, architectural, transportation and industrial markets, which the Company believes will pair well with its existing Engineered Materials business, inclusive of the PMMA Acquisition completed earlier in 2021, discussed further below. Aristech Surfaces’ products are used for a variety of applications, including the construction of hot tubs, swim spas, counter tops, signage, bath products and recreational vehicles. The preliminary purchase price consideration for the Aristech Surfaces Acquisition amounted to $449.7 million, subject to customary working capital and other closing adjustments, and was funded using the Company’s available cash and existing credit facilities. Refer to Note 8 for further information on the existing credit facilities used to fund the Aristech Surfaces Acquisition. The Company accounted for the Aristech Surfaces Acquisition as a business combination pursuant to ASC 805. In accordance with ASC 805, fair values are assigned to tangible and identifiable intangible assets acquired and liabilities assumed at the acquisition date based on the information that was available as of the acquisition date. The Company believes that the information available provides a reasonable basis for estimating the fair values of assets acquired and liabilities assumed for the acquisition, however, preliminary measurements of fair value, including, but not limited to, inventory, intangible assets, property, plant and equipment, contingent liabilities, and such changes could be material. During the measurement period, if new information is obtained about facts and circumstances that existed as of the acquisition date that, if known, would have resulted in revised estimated values of those assets or liabilities as of that date we will revise the preliminary purchase price allocation. The effect of measurement period adjustments to the estimated fair values will be reflected as if the adjustments had been completed on the acquisition date. The impact of all changes that do not qualify as measurement period adjustments will be included in current period earnings. The Company allocated the purchase price of the acquisition to identifiable assets acquired and liabilities assumed based on their estimated fair values as of the acquisition date. The excess of the purchase price over the aggregate fair values was recorded as goodwill. The Company calculated the fair value of the assets acquired using the income and cost approaches (or a combination thereof). Fair values were determined based on various inputs including estimated future cash flows, discount rates, royalty rates, growth rates, sales projections, retention rates and terminal values, all of which require significant management judgment. The table below summarizes the purchase price allocation for the assets acquired and liabilities assumed, based on their relative fair values, which have been assessed as of the September 1, 2021 acquisition date: ​ ​ ​ ​ ​ ​ ​ ​ September 1, ​ ​ 2021 ​ Cash and cash equivalents ​ $ 1.7 ​ Accounts receivable ​ 26.9 ​ Inventories (1) ​ 30.3 ​ Other current assets ​ 1.9 ​ Property, plant and equipment ​ 75.3 ​ Other intangible assets (2) ​ ​ ​ ​ Customer relationships ​ 145.0 ​ Developed technology ​ 52.5 ​ Tradenames ​ ​ 10.0 ​ Other amortizable intangible assets ​ ​ 0.3 ​ Right-of-use assets - operating ​ 2.0 ​ Deferred charges and other assets ​ ​ 0.8 ​ Total fair value of assets acquired ​ ​ 346.7 ​ ​ ​ ​ ​ ​ Accounts payable ​ ​ (13.8) ​ Current lease liabilities - operating ​ (0.4) ​ Accrued expenses and other current liabilities ​ ​ (3.1) ​ Noncurrent lease liabilities - operating ​ ​ (1.6) ​ Other noncurrent obligations ​ ​ (1.4) ​ Total fair value of liabilities assumed ​ ​ (20.3) ​ Net identifiable assets acquired ​ ​ 326.4 ​ Purchase price consideration ​ ​ 449.7 ​ Goodwill (3) ​ $ 123.3 ​ (1) Fair value of work-in-process and finished goods inventory acquired included a step-up in the value of approximately $6.9 million, out of which $3.5 million was amortized during the third quarter of 2021 within "Cost of sales" on the condensed consolidated statements of operations as the related inventory was sold to customers. (2) The expected weighted average useful life of the acquired intangible assets are 13 years for customer relationships, 11 years for developed technology, and 10 years for tradenames and 1 - 5 years for other amortizable intangible assets. (3) Goodwill largely consists of strategic and synergistic opportunities resulting from combining Aristech Surfaces with the Company’s existing businesses and is allocated entirely to the Engineered Materials segment. All of the goodwill related to this acquisition will be deductible for income tax purposes. Net sales and net loss of Aristech Surfaces between the September 1, 2021 acquisition date and September 30, 2021 were $ 14.8 million and $ 3.1 million, respectively, and are recognized within the Company's condensed consolidated statements of operations for the three and nine months ended September 30, 2021. Transaction-related costs Pursuant to GAAP, costs incurred to complete the Aristech Surfaces Acquisition as well as costs incurred to integrate into our operations are expensed as incurred. The Company incurred $3.1 million and $3.4 million of transaction-related costs for the three and nine months ended September 30, 2021, respectively. The amounts were recorded within “Selling, general and administrative expenses” in the Company’s condensed consolidated statements of operations, and are reflected in the nine months ended September 30, 2020 in the supplemental pro forma information below. Acquisition of the Arkema PMMA Business On May 3, 2021, the Company completed its previously-announced acquisition of the polymethyl methacrylates (“PMMA”) and activated methyl methacrylates (“MMA”) business (together, the “PMMA business”) from Arkema PLC, (“Arkema”) through the purchase of 100% of the shares of certain subsidiaries of Arkema (the “PMMA Acquisition”). The PMMA Acquisition was completed pursuant to the Share Purchase Agreement, dated March 19, 2021 (the “SPA”), by and between the Company and Arkema. PMMA is a transparent and rigid plastic with a wide range of end uses, and is an attractive adjacent chemistry which complements Trinseo’s existing offerings across several end markets including automotive, building & construction, medical and consumer electronics. ​ The following table illustrates each component of the purchase price consideration related to the PMMA Acquisition: ​ ​ ​ ​ ​ ​ ​ Initial cash purchase price paid (1) $ 1,369.0 Known purchase price adjustment, not yet settled (2) ​ (4.1) Total purchase price consideration ​ $ 1,364.9 (1) The PMMA Acquisition had an initial purchase price consideration of $1,370.7 million, of which $1,369.0 million was paid during the second quarter of 2021. This initial purchase price consideration remains subject to customary working capital and other closing adjustments. (2) Known purchase price adjustment not yet paid relates primarily to consideration for estimated working capital adjustments and certain assets at the Porto Marghera, Italy manufacturing site which will be legally transferred to Trinseo at a later date due to local transfer restrictions; however, the Company has the benefits and risks of ownership during the period from May 3, 2021 until the site legally transfers. This purchase price consideration is expected to be paid in the fourth quarter of 2021. The PMMA Acquisition was funded using the net proceeds from the Company’s new financing arrangements, including $450.0 million from its 2029 Senior Notes issued on March 24, 2021 and $750.0 million of incremental borrowings under the 2028 Term Loan B entered into in conjunction with closing of the transaction, as well as available cash. Refer to Note 8 for further information on the financing arrangements used to fund the PMMA Acquisition. The Company accounted for the PMMA Acquisition as a business combination pursuant to ASC 805. In accordance with ASC 805, fair values are assigned to tangible and identifiable intangible assets acquired and liabilities assumed at the acquisition date based on the information that was available as of that date. The Company believes that the information available provides a reasonable basis for estimating the fair values of assets acquired and liabilities assumed for the PMMA Acquisition; however, preliminary measurements of fair value, including, but not limited to, inventory, intangible assets, property, plant and equipment, pension and postretirement obligations, contingent liabilities, including environmental remediation obligations, and deferred tax assets and liabilities are subject to change during the measurement period, and such changes could be material. The Company expects to finalize the valuation and accounting for the PMMA Acquisition as soon as practicable, but no later than one year after the acquisition date. During the measurement period, if new information is obtained about facts and circumstances that existed as of the acquisition date that, if known, would have resulted in revised estimated values of those assets or liabilities as of that date, the Company will revise the preliminary purchase price allocation. The effect of measurement period adjustments to the estimated fair values will be reflected as if the adjustments had been completed on the acquisition date. The impact of all changes that do not qualify as measurement period adjustments will be included in current period earnings. The Company allocated the purchase price of the PMMA Acquisition to identifiable assets acquired and liabilities assumed based on their estimated fair values as of the acquisition date. The excess of the purchase price over the aggregate fair values was recorded as goodwill. The Company calculated the fair value of the assets acquired using the income and cost approaches (or a combination thereof). Fair values were determined based on various inputs including estimated future cash flows, discount rates, royalty rates, growth rates, sales projections, customer retention rates and terminal values. The fair value of pension liabilities assumed was determined in accordance with ASC 715 using key inputs including, but not limited to, discount rates, expected rates of return on plan assets, and future compensation growth rates. The various inputs used in the asset and pension valuations require significant management judgment. The table below summarizes the preliminary purchase price allocation for the assets acquired and liabilities assumed, based on their relative fair values. In the third quarter of 2021, the Company recorded certain measurement period adjustments to reflect facts and circumstances in existence as of the May 3, 2021 acquisition date. These adjustments included a $19.4 million increase to property, plant and equipment, a $5.0 million increase to deferred income tax liabilities, a $5.8 million decrease to purchase price consideration, and a resulting $20.1 million decrease to goodwill. ​ ​ ​ ​ ​ ​ ​ May 3, ​ 2021 Cash and cash equivalents ​ $ 10.4 Accounts receivable ​ 19.1 Inventories (1) ​ 78.9 Other current assets ​ 8.7 Property, plant and equipment ​ 255.4 Other intangible assets (2) ​ ​ ​ Customer relationships ​ 326.6 Developed technology ​ 133.0 Tradenames ​ ​ 46.0 Other amortizable intangible assets ​ ​ 0.4 Right-of-use assets - operating ​ 4.1 Deferred charges and other assets ​ ​ 27.9 Total fair value of assets acquired ​ ​ 910.5 ​ ​ ​ ​ Accounts payable ​ ​ (15.0) Current lease liabilities - operating ​ (1.7) Income taxes payable ​ ​ (0.3) Accrued expenses and other current liabilities ​ ​ (11.3) Noncurrent lease liabilities - operating ​ ​ (2.5) Deferred income tax liabilities ​ ​ (39.3) Other noncurrent obligations (3) ​ ​ (23.1) Total fair value of liabilities assumed ​ ​ (93.2) Net identifiable assets acquired ​ ​ 817.3 Purchase price consideration ​ ​ 1,364.9 Goodwill (4) ​ $ 547.6 (1) Fair value of finished goods inventory acquired included a step-up in the value of approximately $10.1 million, which was fully amortized during the second quarter of 2021 within "Cost of sales" on the condensed consolidated statements of operations as the related inventory was sold to customers. (2) The expected weighted average useful life of the acquired intangible assets are 13 years for customer relationships, 10 years for developed technology, 16 years for tradenames, and 1 - 5 years for other amortizable intangible assets. (3) Includes $18.2 million of net pension and other employee benefits assumed as part of the PMMA Acquisition. (4) Goodwill largely consists of strategic and synergistic opportunities resulting from combining the PMMA business with the Company’s existing businesses and is allocated entirely to the Engineered Materials segment. Approximately $310.0 million of goodwill related to this acquisition will be deductible for income tax purposes based on the preliminary purchase price. The results of the PMMA business are recognized within the Company's condensed consolidated statements of operations since the closing of the acquisition on May 3, 2021. The PMMA business contributed net sales and net loss of $224.6 million and $1.6 million, respectively, to the Company’s results for the three months ended September 30, 2021. The PMMA business acquisition contributed net sales and net loss of $332.1 million and $5.4 million, respectively, to the Company’s results for the period from May 3, 2021 to September 30, 2021. Transaction-related costs Pursuant to GAAP, costs incurred to complete the PMMA Acquisition as well as costs incurred to integrate into our operations are expensed as incurred. The Company incurred $0.2 million and $20.0 million of transaction-related costs for the three and nine months ended September 30, 2021, respectively. The amounts were recorded within “Selling, general and administrative expenses” in the Company’s condensed consolidated statements of operations, and are reflected in the nine months ended September 30, 2020 in the supplemental pro forma information below. In connection with the PMMA Acquisition, the Company entered into certain customary transitional services agreements with Arkema to provide for the orderly separation and transition of various functions and processes. These services will be provided by Arkema to the Company for up to 18 months after closing, with certain extension options available. These services include information technology, accounting and finance, procurement, supply chain, and other services, while we assume the operations of the PMMA business. Additionally, the Company paid Arkema $10.6 million for certain information technology separation costs in order to support the transition services agreements entered into at the time of close. These payments have not been included as a component of consideration transferred, and instead have been capitalized as prepaid assets within “Other current assets” on the condensed consolidated balance sheets. The cost will be recognized as expense over the period in which the services are expected to be rendered under the transition services agreements. Unaudited Pro Forma Financial Information The following unaudited pro forma financial information presents the condensed consolidated results of operations of the Company with the PMMA business and Aristech Surfaces for the three and nine months ended September 30, 2021 and 2020, respectively, as if these acquisitions had occurred on January l, 2020. The proforma results were calculated by combining the results of Trinseo with the PMMA business and Aristech Surfaces but do not include adjustments related to cost savings or other synergies that are anticipated as a result of these acquisitions. Accordingly, these unaudited pro forma results are presented for informational purposes only and are not necessarily indicative of what the actual results of operations would have been if the acquisitions had occurred as of January 1, 2020, nor are they indicative of future results of operations. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2021 2020 2021 2020 Net sales $ 1,300.2 $ 862.0 $ 3,863.8 $ 2,499.7 Net income (loss) ​ $ 94.1 ​ $ 104.0 ​ $ 355.1 ​ $ (96.7) Income (loss) from continuing operations ​ $ 80.4 ​ $ 38.4 ​ $ 317.1 ​ $ (41.3) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Divestitures and Discontinued O

Divestitures and Discontinued Operations9 Months Ended
Sep. 30, 2021
Divestitures
Divestitures and Discontinued OperationsNOTE 4—DIVESTITURES AND DISCONTINUED OPERATIONS On May 21, 2021, the Company and Synthos PLC and certain of its subsidiaries (together, “Synthos”) entered into an Asset Purchase Agreement (the “Purchase Agreement”), pursuant to which the Company agreed to sell its Synthetic Rubber business to Synthos in an all-cash transaction with an initial aggregate price of $449.4 million, which reflects a reduction of approximately $41.6 million for the assumption of pension liabilities by Synthos. This initial aggregate purchase price included a working capital target (excluding inventory) of $47.0 million, which was subject to adjustment based on actual amounts conveyed at closing. On October 21, 2021, the Company and Synthos entered into an amendment to the Purchase Agreement (the “Amended Purchase Agreement”), whereby net working capital (excluding inventory) will not transfer with the sale of the Synthetic Rubber business and, in exchange, the working capital target of $47.0 million will be removed from the purchase price. This will result in an amended purchase price of $402.4 million, subject to certain adjustments related to inventory and the exercise of certain option rights related to equity investments held by the Company. This sale is expected to close in December 2021, subject to customary closing conditions. As a result of the above agreements, the assets and liabilities of the Company’s Synthetic Rubber business were classified as held-for-sale starting in the second quarter of 2021 in the condensed consolidated balance sheets and the associated operating results of the Synthetic Rubber business, net of income tax, have been classified as discontinued operations in the condensed consolidated statements of operations and statements of cash flows for all periods presented, in accordance with the guidance in ASC 205-20, Discontinued Operations. The following table summarizes the assets and liabilities classified as held-for-sale at September 30, 2021 and December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ ​ 2021 ​ 2020 ​ Assets ​ ​ ​ ​ ​ Current assets ​ ​ ​ ​ ​ ​ ​ Accounts receivable, net of allowance ​ $ 83.5 ​ $ 59.7 ​ Inventories and other current assets ​ 89.2 ​ 60.6 ​ Total current assets ​ 172.7 ​ 120.3 ​ Property, plant and equipment, net ​ ​ 152.3 ​ ​ 170.3 ​ Other assets ​ ​ ​ ​ ​ ​ ​ Goodwill ​ 11.4 ​ 12.1 ​ Other intangible assets, net ​ 17.5 ​ 20.2 ​ Deferred charges and other assets ​ 25.6 ​ 25.6 ​ Total other assets ​ 54.5 ​ 57.9 ​ Total assets held-for-sale (1) ​ $ 379.5 ​ $ 348.5 ​ Liabilities ​ ​ ​ ​ ​ ​ ​ Current liabilities ​ ​ ​ ​ ​ ​ ​ Accounts payable ​ 27.6 ​ 29.5 ​ Accrued expenses and other current liabilities ​ ​ 11.3 ​ ​ 12.7 ​ Total current liabilities ​ 38.9 ​ 42.2 ​ Noncurrent liabilities ​ ​ ​ ​ ​ ​ ​ Other noncurrent obligations ​ 42.4 ​ 42.3 ​ Total noncurrent liabilities ​ 42.4 ​ 42.3 ​ Total liabilities held-for-sale (1) ​ $ 81.3 ​ $ 84.5 ​ (1) All balance sheet amounts as of September 30, 2021 have been classified as current within the condensed consolidated balance sheets, as the sale is expected to occur within one year of the balance sheet date. The following table summarizes the results of the Synthetic Rubber business for the three and nine months ended September 30, 2021 and 2020, which are reflected as discontinued operations in the Company’s condensed consolidated statements of operations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2021 2020 2021 2020 Net sales $ 122.3 $ 79.5 $ 382.2 $ 217.5 Cost of sales ​ 101.9 ​ 82.5 ​ 321.2 ​ 238.9 Gross profit (loss) ​ 20.4 ​ (3.0) ​ 61.0 ​ (21.4) Selling, general and administrative expenses ​ 4.9 ​ 7.4 ​ 16.7 ​ 17.8 Impairment charges ​ ​ — ​ ​ — ​ ​ — ​ ​ 28.0 Operating income (loss) ​ 15.5 ​ (10.4) ​ 44.3 ​ (67.2) Other expense, net ​ ​ 0.2 ​ ​ 0.4 ​ ​ 1.2 ​ ​ 1.1 Income (loss) from discontinued operations before income taxes ​ 15.3 ​ (10.8) ​ 43.1 ​ (68.3) Provision for (benefit from) income taxes ​ 1.6 ​ (76.4) ​ 5.1 ​ (12.9) Net income (loss) from discontinued operations ​ $ 13.7 ​ $ 65.6 ​ $ 38.0 ​ $ (55.4) ​ Amounts for operating net sales and costs of sales which had previously been eliminated in consolidation related to intercompany sales of styrene monomer to the Synthetic Rubber business are now reflected on a gross basis as a component of net sales and costs of sales from continuing operations for all periods presented. The Company has recast these amounts because upon completion of the sale of the Synthetic Rubber business, the Company will continue to have these ongoing transactions with Synthos, under a supply agreement executed in conjunction with the divestiture. Refer to Note 5 for recast segment net sales reflecting this adjustment. Additionally, the Company previously allocated certain corporate management overhead costs to the former Synthetic Rubber segment which may no longer be allocated to discontinued operations under the relevant authoritative accounting guidance. Accordingly, the Company has recast its segment reporting results to reflect the reattribution of these expenses in all periods presented. Refer to Note 16 for recast segment results reflecting this adjustment.

Net Sales

Net Sales9 Months Ended
Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Net SalesNOTE 5—NET SALES Refer to the Annual Report for information on the Company's accounting policies and further background related to its net sales. The following table provides disclosure of net sales to external customers by primary geographical market (based on the location where sales originated), by segment for the three and nine months ended September 30, 2021 and 2020. Prior period balances in this table have been recast to reflect current period presentation, as described in Notes 1 and 4, including updates for the classification of the Company’s former Synthetic Rubber segment as discontinued operations and the Company’s prior year resegmentation. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Latex ​ Engineered ​ Base ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Binders ​ Materials ​ Plastics ​ Polystyrene ​ Feedstocks ​ Total September 30, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ United States ​ $ 86.3 ​ $ 102.4 ​ $ 82.3 ​ $ — ​ $ 4.0 ​ $ 275.0 ​ Europe ​ 153.5 ​ 89.6 ​ 247.3 ​ 162.6 ​ 50.8 ​ 703.8 ​ Asia-Pacific ​ 73.0 ​ 35.9 ​ 43.9 ​ 112.2 ​ — ​ 265.0 ​ Rest of World ​ 2.8 ​ 2.9 ​ 19.8 ​ — ​ — ​ 25.5 ​ Total ​ $ 315.6 ​ $ 230.8 ​ $ 393.3 ​ $ 274.8 ​ $ 54.8 ​ $ 1,269.3 ​ September 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ United States ​ $ 54.1 ​ $ 8.0 ​ $ 52.8 ​ $ — ​ $ 2.0 ​ $ 116.9 ​ Europe ​ 79.7 ​ 13.8 ​ ​ 126.8 ​ 96.9 ​ 31.7 ​ 348.9 ​ Asia-Pacific ​ 48.1 ​ 28.1 ​ ​ 40.9 ​ 70.4 ​ 4.9 ​ ​ 192.4 ​ Rest of World ​ 1.3 ​ 0.1 ​ ​ 19.6 ​ — ​ — ​ 21.0 ​ Total ​ $ 183.2 ​ $ 50.0 ​ $ 240.1 ​ $ 167.3 ​ $ 38.6 ​ $ 679.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Latex ​ Engineered ​ Base ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ Binders ​ Materials ​ Plastics ​ Polystyrene ​ Feedstocks ​ Total September 30, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ United States ​ $ 228.2 ​ $ 174.1 ​ $ 216.5 ​ $ — ​ $ 10.7 ​ $ 629.5 ​ Europe ​ 431.4 ​ 190.8 ​ 699.2 ​ 511.7 ​ 188.9 ​ 2,022.0 ​ Asia-Pacific ​ 211.1 ​ 108.1 ​ 144.5 ​ 343.3 ​ — ​ 807.0 ​ Rest of World ​ 6.9 ​ 4.5 ​ 59.1 ​ — ​ — ​ 70.5 ​ Total ​ $ 877.6 ​ $ 477.5 ​ $ 1,119.3 ​ $ 855.0 ​ $ 199.6 ​ $ 3,529.0 ​ September 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ United States ​ $ 167.2 ​ $ 25.3 ​ $ 143.5 ​ $ — ​ $ 5.9 ​ $ 341.9 ​ Europe ​ 254.0 ​ 37.4 ​ ​ 366.1 ​ 301.8 ​ 93.4 ​ 1,052.7 ​ Asia-Pacific ​ 140.9 ​ 72.3 ​ ​ 94.5 ​ 204.1 ​ 19.7 ​ ​ 531.5 ​ Rest of World ​ 5.2 ​ 0.2 ​ ​ 45.0 ​ — ​ — ​ 50.4 ​ Total ​ $ 567.3 ​ $ 135.2 ​ $ 649.1 ​ $ 505.9 ​ $ 119.0 ​ $ 1,976.5 ​ ​

Investments in Unconsolidated A

Investments in Unconsolidated Affiliates9 Months Ended
Sep. 30, 2021
Investments in Unconsolidated Affiliates
Investments in Unconsolidated AffiliatesNOTE 6—INVESTMENTS IN UNCONSOLIDATED AFFILIATES The Company is currently supplemented by one joint venture, Americas Styrenics LLC (“Americas Styrenics,” a styrene and polystyrene joint venture with Chevron Phillips Chemical Company LP), which is accounted for using the equity method. The results of Americas Styrenics are included within its own reporting segment. Americas Styrenics is a privately held company; therefore, a quoted market price for its equity interests is not available. The summarized financial information of the Company’s unconsolidated affiliate is shown below. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2021 2020 2021 2020 Sales $ 433.4 $ 269.7 $ 1,351.9 $ 817.3 ​ Gross profit ​ $ 49.3 ​ $ 39.6 ​ $ 189.2 ​ $ 78.1 ​ Net income ​ $ 37.2 ​ $ 27.5 ​ $ 151.8 ​ $ 39.3 ​ ​ As of September 30, 2021 and December 31, 2020, the Company’s investment in Americas Styrenics was $250.3 million and $240.1 million, respectively, which was $10.6 million and $16.3 million greater than the Company’s 50% share of the underlying net assets of Americas Styrenics, respectively. This amount represents the difference between the book value of assets held by the joint venture and the Company’s 50% share of the total recorded value of the joint venture’s assets, inclusive of certain adjustments to conform with the Company’s accounting policies. This difference is being amortized over a weighted average remaining useful life of approximately 2.6 years as of September 30, 2021. The Company received dividends of $20.0 million and $60.0 million from Americas Styrenics during the three and nine months ended September 30, 2021, respectively, while no dividends were received during the three and nine months ended September 30, 2020.

Inventories

Inventories9 Months Ended
Sep. 30, 2021
Inventories
InventoriesNOTE 7—INVENTORIES Inventories consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 ​ 2020 Finished goods $ 314.0 $ 132.9 Raw materials and semi-finished goods ​ 265.5 ​ 161.7 Supplies ​ 37.8 ​ 29.5 Total ​ $ 617.3 ​ $ 324.1 ​

Debt

Debt9 Months Ended
Sep. 30, 2021
Debt
DebtNOTE 8—DEBT Refer to the Annual Report for definitions of capitalized terms not included herein and further background on the Company’s debt structure discussed below. The Company was in compliance with all debt related covenants as of September 30, 2021 and December 31, 2020. As of September 30, 2021 and December 31, 2020, debt consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ December 31, 2020 ​ ​ Interest Rate as of Maturity Date Carrying Amount Unamortized Deferred Financing Fees (1) Total Debt, Less Unamortized Deferred Financing Fees Carrying Amount Unamortized Deferred Financing Fees (1) Total Debt, Less ​ Senior Credit Facility ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2024 Term Loan B ​ 2.081% ​ September 2024 ​ $ 672.1 ​ $ (8.7) ​ $ 663.4 ​ $ 677.3 ​ $ (10.8) ​ $ 666.5 ​ 2028 Term Loan B ​ 2.584% ​ May 2028 ​ ​ 744.6 ​ ​ (17.6) ​ ​ 727.0 ​ ​ — ​ ​ — ​ ​ — ​ 2026 Revolving Facility (2) ​ Various ​ May 2026 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ 2029 Senior Notes ​ 5.125% ​ April 2029 ​ ​ 450.0 ​ ​ (15.1) ​ ​ 434.9 ​ ​ — ​ ​ — ​ ​ — ​ 2025 Senior Notes ​ 5.375% ​ September 2025 ​ ​ 500.0 ​ ​ (5.3) ​ ​ 494.7 ​ ​ 500.0 ​ ​ (6.2) ​ ​ 493.8 ​ Accounts Receivable Securitization Facility (3) ​ Various ​ November 2021 ​ ​ 130.0 ​ ​ — ​ ​ 130.0 ​ ​ — ​ ​ — ​ ​ — ​ Other indebtedness ​ Various ​ Various ​ ​ 7.0 ​ ​ — ​ ​ 7.0 ​ ​ 10.0 ​ ​ — ​ ​ 10.0 ​ Total debt ​ ​ ​ ​ ​ $ 2,503.7 ​ $ (46.7) ​ $ 2,457.0 ​ $ 1,187.3 ​ $ (17.0) ​ $ 1,170.3 ​ Less: current portion (4) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (149.1) ​ ​ ​ ​ ​ ​ ​ ​ (12.2) ​ Total long-term debt, net of unamortized deferred financing fees ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 2,307.9 ​ ​ ​ ​ ​ ​ ​ $ 1,158.1 ​ (1) This caption does not include deferred financing fees related to the Company’s revolving facilities, which are included within “Deferred charges and other assets” on the condensed consolidated balance sheets. (2) On May 3, 2021, in conjunction with the PMMA Acquisition, the Company extended its Revolving Facility (previously the “2022 Revolving Facility,” now the “2026 Revolving Facility”), originally maturing in September 2022, to May 2026, as described further below. As of September 30, 2021, under the 2026 Revolving Facility, the Company had a capacity of $375.0 million and funds available for borrowing of $366.9 million (net of $8.1 million outstanding letters of credit). Additionally, the Company is required to pay a quarterly commitment fee in respect of any unused commitments under this facility equal to 0.375% per annum. (3) On August 27, 2021, in conjunction with the Aristech Surfaces Acquisition, the Company drew $150.0 million on its Accounts Receivable Securitization Facility, of which $20.0 million was repaid in September 2021. Further, in September 2021, the Company extended the maturity date of the facility to November 2021. As of September 30, 2021, this facility had a borrowing capacity of $150.0 million, and the Company had approximately $20.0 million of funds available for borrowing under this facility, based on the pool of eligible accounts receivable. (4) As of September 30, 2021, the current portion of long-term debt was primarily related to a $130.0 million balance on the Accounts Receivable Securitization Facility and $14.5 million of the scheduled future principal payments on both the 2024 Term Loan B and 2028 Term Loan B. As of December 31, 2020, the current portion of long-term debt was primarily related to $7.0 million of the scheduled future principal payments on the 2024 Term Loan B. 2029 Senior Notes On March 24, 2021, Trinseo Materials Operating S.C.A. and Trinseo Materials Finance, Inc. (together, the “Issuers”), each an indirect, wholly-owned subsidiary of the Company, executed an indenture pursuant to which they issued $450.0 million aggregate principal amount of 5.125% senior notes due 2029 (the “2029 Senior Notes”) in a 144A private transaction exempt from the registration requirements of the Securities Act of 1933, as amended. Interest on the 2029 Senior Notes is payable semi-annually on February 15 and August 15 of each year, commencing on August 15, 2021. The 2029 Senior Notes mature on April 1, 2029. The net proceeds from the 2029 Senior Notes offering were used as a portion of the funding needed for the PMMA Acquisition, in addition to fees and expenses related to the offering and the PMMA Acquisition. The gross proceeds from the 2029 Senior Notes offering were released upon satisfaction of certain escrow release conditions, including closing of the PMMA Acquisition, which was completed on May 3, 2021. At any time prior to April 1, 2024, the Issuers may redeem the 2029 Senior Notes in whole or in part, at their option, at a redemption price equal to 100% of the principal amount of such notes plus the relevant applicable premium as of, and accrued and unpaid interest to, but not including, the redemption date. At any time and from time to time after April 1, 2024, the Issuers may redeem the 2029 Senior Notes, in whole or in part, at a redemption price equal to the percentage of principal amount set forth below plus accrued and unpaid interest, if any, on the notes redeemed to, but not including, the redemption date: ​ ​ ​ ​ ​ 12-month period commencing April 1 in Year ​ Percentage ​ 2024 102.563 % 2025 101.281 % 2026 and thereafter 100.000 % ​ At any time prior to April 1, 2024, the Issuers may redeem up to 40% of the aggregate principal amount of the 2029 Senior Notes at a redemption price equal to 105.125%, plus accrued and unpaid interest to, but not including, the redemption date, with the aggregate gross proceeds from certain equity offerings. The 2029 Senior Notes are the Issuers’ senior unsecured obligations and rank equally in right of payment with all of the Issuers’ existing and future indebtedness that is not expressly subordinated in right of payment thereto. The 2029 Senior Notes will be senior in right of payment to any future indebtedness that is expressly subordinated in right of payment thereto and effectively junior to (a) the Issuers’ existing and future secured indebtedness, including the Company’s accounts receivable facility and the Issuers’ Credit Facility, to the extent of the value of the collateral securing such indebtedness and (b) all existing and future liabilities of the Issuers’ non-guarantor subsidiaries. The Indenture contains customary covenants, including restrictions on the Issuers’ and certain of its subsidiaries’ ability to incur additional indebtedness and guarantee indebtedness; pay dividends on, redeem or repurchase capital stock; make investments; prepay certain indebtedness; create liens; enter into transactions with the Issuers’ affiliates; designate the Issuers’ subsidiaries as Unrestricted Subsidiaries (as defined in the Indenture); and consolidate, merge, or transfer all or substantially all of the Issuers’ assets. The covenants are subject to a number of exceptions and qualifications. Certain of these covenants, excluding without limitation those relating to transactions with the Issuers’ affiliates and consolidation, merger, or transfer of all or substantially all of the Issuers’ assets, will be suspended during any period of time that (1) the 2029 Senior Notes have Investment Grade Status (as defined in the Indenture) and (2) no default has occurred and is continuing under the Indenture. In the event that the 2029 Senior Notes are downgraded to below an Investment Grade Status, the Issuers and certain subsidiaries will again be subject to the suspended covenants with respect to future events. Total fees incurred in connection with the issuance of the 2029 Senior Notes were $15.9 million, which were capitalized and recorded within “Long-term debt, net of unamortized deferred financing fees” on the condensed consolidated balance sheet, and are being amortized into “Interest expense, net” in the condensed consolidated statements of operations over their eight-year term using the effective interest method. Senior Credit Facility On May 3, 2021, the Issuers entered into (i) an amendment to the existing credit agreement dated as of September 6, 2017 in which the Issuers borrowed a new tranche of term loans in an aggregate amount of $750.0 million senior secured term loan B facility maturing in May 2028 (the “2028 Term Loan B”), used to finance a portion of the purchase price of the PMMA Acquisition, and (ii) an amendment to the existing credit agreement, pursuant to which the existing revolving credit facility has been refinanced with a new revolving credit facility in an aggregate amount of $375.0 million, with a $25.0 million swingline subfacility and a $35.0 million letter of credit subfacility, maturing in May 2026. Amounts under the 2026 Revolving Facility are available in U.S. dollars and euros. The terms under the 2026 Revolving Facility are substantially unchanged from the 2022 Revolving Facility. Refer to the Annual Report for the terms of the 2022 Revolving Facility. As a result of amending the revolving credit facility, during the nine months ended September 30, 2021, the Company recognized a $0.5 million loss on extinguishment of long-term debt related to the write-off of a portion of the existing unamortized deferred financing fees. This amount has been recorded with “Other expense (income), net” in the condensed consolidated statement of operations. The 2028 Term Loan B bears an interest rate of LIBOR plus 2.50%, subject to a 0.00% LIBOR floor, and was issued at a 0.5% original issue discount. Further, the 2028 Term Loan B requires scheduled quarterly payments in amounts equal to 0.25% of the original principal amount of the 2028 Term Loan B, with the balance to be paid at maturity. The 2026 Revolving Facility contains a financial covenant that requires compliance with a springing first lien net leverage ratio test. If the outstanding balance under the 2026 Revolving Facility exceeds 30% of the $375.0 million borrowing capacity (excluding undrawn letters of credit up to $10.0 million and cash collateralized letters of credit) at a quarter end, then the Borrowers’ first lien net leverage ratio may not exceed 3.50 to 1.00. As of September 30, 2021, the Company was in compliance with all debt covenant requirements under the Senior Credit Facility. Fees incurred in connection with the issuance of the 2028 Term Loan B were $18.7 million, which were capitalized and recorded within “Long-term debt, net of unamortized deferred financing fees” on the condensed consolidated balance sheet, and are being amortized into “Interest expense, net” in the condensed consolidated statements of operations over their seven-year term using the effective interest method. Fees incurred in connection with the 2026 Revolving Facility were $0.4 million, which were capitalized and recorded within “Deferred charges and other assets” on the condensed consolidated balance sheet, and are being amortized along with the remaining $0.8 million of unamortized deferred financing fees from the Company’s former revolving credit facility (“2022 Revolving Facility”) into “Interest expense, net” in the condensed consolidated statements of operations over the five-year term of the facility using the straight-line method.

Goodwill

Goodwill9 Months Ended
Sep. 30, 2021
Goodwill.
GoodwillNOTE 9—GOODWILL The following table shows changes in the carrying amount of goodwill, by segment, from December 31, 2020 to September 30, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Latex ​ Engineered ​ Base ​ ​ ​ ​ ​ Americas ​ ​ ​ ​ Binders ​ Materials Plastics Polystyrene Feedstocks Styrenics Total Balance at December 31, 2020 ​ $ 17.1 ​ $ 16.0 ​ $ 24.2 ​ $ 4.8 ​ $ — ​ $ — ​ $ 62.1 ​ Acquisitions (Note 3) ​ ​ — ​ ​ 670.8 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 670.8 ​ Foreign currency impact ​ (1.0) ​ ​ (10.5) ​ ​ (1.3) ​ ​ (0.2) ​ ​ — ​ ​ — ​ (13.0) ​ Balance at September 30, 2021 ​ $ 16.1 ​ $ 676.3 ​ $ 22.9 ​ $ 4.6 ​ $ — ​ $ — ​ $ 719.9 ​ ​

Derivative Instruments

Derivative Instruments9 Months Ended
Sep. 30, 2021
Derivative Instruments [Abstract]
Derivative InstrumentsNOTE 10—DERIVATIVE INSTRUMENTS The Company’s ongoing business operations expose it to various risks, including fluctuating foreign exchange rates and interest rate risk. To manage these risks, the Company periodically enters into derivative financial instruments, such as foreign exchange forward contracts and interest rate swap agreements. The Company does not hold or enter into financial instruments for trading or speculative purposes. All derivatives are recorded on the condensed consolidated balance sheets at fair value. Foreign Exchange Forward Contracts Certain subsidiaries have assets and liabilities denominated in currencies other than their respective functional currencies, which creates foreign exchange risk. The Company’s principal strategy in managing its exposure to changes in foreign currency exchange rates is to naturally hedge the foreign currency-denominated liabilities on its balance sheet against corresponding assets of the same currency, such that any changes in liabilities due to fluctuations in exchange rates are offset by changes in their corresponding foreign currency assets. In order to further reduce this exposure, the Company also uses foreign exchange forward contracts to economically hedge the impact of the variability in exchange rates on assets and liabilities denominated in certain foreign currencies. The Company entered into a specific such foreign exchange forward contract in December 2020 in order to economically hedge the euro-denominated purchase price of the Arkema PMMA business, which was acquired on May 3, 2021, as discussed in Note 3. These derivative contracts are not designated for hedge accounting treatment. As of September 30, 2021, the Company had open foreign exchange forward contracts with a notional U.S. dollar equivalent absolute value of $1,177.9 million. The following table displays the notional amounts of the most significant net foreign exchange hedge positions outstanding as of September 30, 2021: ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ Buy / (Sell) 2021 ​ Euro ​ $ (1,037.4) ​ Chinese Yuan ​ $ (38.6) ​ Swiss Franc ​ $ 32.8 ​ Mexican Peso ​ $ (17.8) ​ Korean Won ​ $ (15.3) ​ ​ Open foreign exchange forward contracts as of September 30, 2021 had maturities occurring over a period of two months. Foreign Exchange Cash Flow Hedges The Company also enters into forward contracts with the objective of managing the currency risk associated with forecasted U.S. dollar-denominated raw materials purchases by one of its subsidiaries whose functional currency is the euro. By entering into these forward contracts, which are designated as cash flow hedges, the Company buys a designated amount of U.S. dollars and sells euros at the prevailing market rate to mitigate the risk associated with the fluctuations in the euro-to-U.S. dollar foreign currency exchange rates. The qualifying hedge contracts are marked-to-market at each reporting date and any unrealized gains or losses are included in Accumulated Other Comprehensive Income (“AOCI”) to the extent effective, and reclassified to cost of sales in the period during which the transaction affects earnings or it becomes probable that the forecasted transaction will not occur. Open foreign exchange cash flow hedges as of September 30, 2021 had maturities occurring over a period of three months, and had a net notional U.S. dollar equivalent of $24.0 million. Interest Rate Swaps On September 6, 2017, the Company issued the 2024 Term Loan B, which currently bears an interest rate of LIBOR plus 2.00%, subject to a 0.00% LIBOR floor. In order to reduce the variability in interest payments associated with the Company’s variable rate debt, during 2017 the Company entered into certain interest rate swap agreements to convert a portion of these variable rate borrowings into a fixed rate obligation. These interest rate swap agreements are designated as cash flow hedges, and as such, the contracts are marked-to-market at each reporting date and any unrealized gains or losses are included in AOCI to the extent effective, and reclassified to interest expense in the period during which the transaction affects earnings or it becomes probable that the forecasted transaction will not occur. As of September 30, 2021, the Company had open interest rate swap agreements with a net notional U.S. dollar equivalent of $200.0 million which had an effective date of September 29, 2017 and mature in September 2022. Under the terms of the swap agreements, the Company is required to pay the counterparties a stream of fixed interest payments at a rate of 1.81%, and in turn, receives variable interest payments based on 1-month LIBOR (0.08% as of September 30, 2021) from the counterparties. Net Investment Hedge The Company accounts for its cross currency swaps (“CCS”) under the spot method, meaning that changes in the fair value of the hedge included in the assessment of effectiveness (changes due to spot foreign exchange rates) are recorded within AOCI, where they remain until either the sale or substantially complete liquidation of the subsidiary subject to the hedge. Additionally, the initial value of any component excluded from the assessment of effectiveness is recognized in income using a systematic and rational method over the life of the hedging instrument and any difference between the change in the fair value of the excluded component and amounts recognized in income under that systematic and rational method is recognized in AOCI. The Company amortizes any initial excluded component value of a CCS as a reduction of “Interest expense, net” in the condensed consolidated statements of operations using the straight-line method over the remaining term of the related CCS. Additionally, interest receipts and payments are accrued under the terms of the Company’s CCS and are recognized within “Interest expense, net” in the condensed consolidated statements of operations. The Company entered into a CCS arrangement (the “2017 CCS”) on September 1, 2017, swapping U.S. dollar principal and interest payments of $500.0 million at an interest rate of 5.375% on its 2025 Senior Notes for euro-denominated payments of €420.0 million at a weighted average interest rate of 3.45% for approximately five years. The 2017 CCS was initially designated under the forward method and then redesignated under the spot method effective April 1, 2018. At the time of redesignation, the 2017 CCS had a cumulative foreign currency translation loss in AOCI of $38.0 million. The excluded component value related to the 2017 CCS at April 1, 2018 was $23.6 million, which was being amortized over its remaining term. On February 26, 2020, the Company settled its 2017 CCS and replaced it with a new CCS arrangement (the “2020 CCS”) that carried substantially the same terms as the 2017 CCS. Upon settlement of the 2017 CCS, the Company realized net cash proceeds of $51.6 million. The remaining $13.8 million unamortized balance of the initial excluded component related to the 2017 CCS at the time of settlement will remain in AOCI until either the sale or substantially complete liquidation of the relevant subsidiaries. Under the 2020 CCS, the Company notionally exchanged $500.0 million at an interest rate of 5.375% for €459.3 million at a weighted average interest rate of 3.672% for approximately 2.7 years, with a final maturity of November 3, 2022. The cash flows under the 2020 CCS are aligned with the Company’s principal and interest obligations on its 5.375% 2025 Senior Notes. Summary of Derivative Instruments The following table presents the effect of the Company’s derivative instruments, including those not designated for hedge accounting treatment, on the condensed consolidated statements of operations for the three and nine months ended September 30, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Location and Amount of Gain (Loss) Recognized in ​ ​ ​ Three Months Ended ​ Three Months Ended ​ ​ ​ September 30, 2021 ​ September 30, 2020 ​ ​ Cost of ​ Interest expense, net ​ Acquisition purchase price hedge gain (loss) ​ Other income, net ​ Cost of ​ Interest expense, net ​ Acquisition purchase price hedge gain (loss) ​ Other expense, net Total amount of income and (expense) line items presented in the statements of operations in which the effects of derivative instruments are recorded ​ $ (1,101.0) ​ $ (23.0) ​ $ — ​ $ 0.1 ​ $ (572.9) ​ $ (10.0) ​ $ — ​ $ (1.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The effects of cash flow hedge instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange cash flow hedges ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain (loss) reclassified from AOCI into income ​ $ 0.3 ​ $ — ​ $ — ​ $ — ​ $ (0.7) ​ $ — ​ $ — ​ $ — ​ Interest rate swaps ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of loss reclassified from AOCI into income ​ $ — ​ $ (0.9) ​ $ — ​ $ — ​ $ — ​ $ (0.8) ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The effects of net investment hedge instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cross currency swaps (CCS) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain excluded from effectiveness testing ​ $ — ​ $ 1.9 ​ $ — ​ $ — ​ $ — ​ $ 1.6 ​ $ — ​ $ — ​ Amount of loss recognized in income (1) ​ $ — ​ $ — ​ $ — ​ $ ​ ​ $ — ​ $ — ​ $ — ​ $ (0.8) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The effects of derivatives not designated as hedge instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange forward contracts ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain (loss) recognized in income ​ $ — ​ $ — ​ $ — ​ $ 23.3 ​ $ — ​ $ — ​ $ — ​ $ (13.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Location and Amount of Gain (Loss) Recognized in ​ ​ Nine Months Ended ​ Nine Months Ended ​ ​ ​ September 30, 2021 ​ September 30, 2020 ​ ​ Cost of Interest expense, net ​ Acquisition purchase price hedge gain (loss) ​ Other expense, net Cost of Interest expense, net ​ Acquisition purchase price hedge gain (loss) ​ Other expense, net Total amount of income and (expense) line items presented in the statements of operations in which the effects of derivative instruments are recorded ​ $ (2,951.7) ​ $ (56.6) ​ $ (22.0) ​ $ (8.4) ​ $ (1,789.1) ​ $ (32.0) ​ $ — ​ $ (3.0) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effects of cash flow hedge instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange cash flow hedges ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain reclassified from AOCI into income ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ Interest rate swaps ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of loss reclassified from AOCI into income ​ $ — ​ $ (2.6) ​ $ — ​ $ — ​ $ — ​ $ (1.6) ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effects of net investment hedge instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cross currency swaps ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain excluded from effectiveness testing (2) ​ $ — ​ $ 5.5 ​ $ — ​ $ — ​ $ — ​ $ 7.0 ​ $ — ​ $ — ​ Amount of loss recognized in income (1) ​ $ — ​ $ — ​ $ — ​ $ ​ ​ $ — ​ $ — ​ $ — ​ $ (0.8) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effects of derivatives not designated as hedge instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange forward contracts ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain (loss) recognized in income (3) ​ $ — ​ $ — ​ $ (22.0) ​ $ 43.4 ​ $ — ​ $ — ​ $ — ​ $ (7.5) ​ (1) Amount represents the change in fair value of the portion of the 2020 CCS that was de-designated from hedge accounting for the three and nine months ended September 30, 2020. (2) Amounts include the effects on AOCI of both the 2017 CCS through its settlement on February 26, 2020 and the 2020 CCS from when it was entered into on February 26, 2020 through September 30, 2020. (3) The $22.0 million loss incurred from the change in fair value of the forward currency hedge arrangement on the euro-denominated purchase price of the Arkema PMMA business during the nine months ended September 30, 2021 is presented separately in the condensed consolidated statements of operations from the gains recorded on the Company’s other foreign exchange forward contracts. The following table presents the effect of cash flow and net investment hedge accounting on AOCI for the three and nine months ended September 30, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ` ​ Gain (Loss) Recognized in AOCI on Balance Sheet ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 Designated as Cash Flow Hedges ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange cash flow hedges $ 0.4 $ (0.3) $ 3.1 $ 0.6 Interest rate swaps ​ ​ 0.8 ​ ​ 0.7 ​ ​ 2.5 ​ ​ (5.2) Total ​ $ 1.2 ​ $ 0.4 ​ $ 5.6 ​ $ (4.6) Designated as Net Investment Hedges ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cross currency swaps (CCS) (1) ​ $ 13.1 ​ $ (24.2) ​ $ 32.1 ​ $ (11.6) Total ​ $ 13.1 ​ $ (24.2) ​ $ 32.1 ​ $ (11.6) (1) Amount for the nine months ended September 30, 2020 includes the effects on AOCI of both the 2017 CCS through its settlement on February 26, 2020 and the 2020 CCS from when it was entered into on February 26, 2020 through September 30, 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain (Loss) Recognized in Other expense, net in Statement of Operations ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2021 2020 2021 2020 ​ Settlements and changes in the fair value of forward contracts (not designated as hedges) (1) $ 23.3 $ (13.2) $ 43.4 $ (7.5) ​ Remeasurement of foreign currency-denominated assets and liabilities ​ $ (23.7) ​ $ 14.0 ​ $ (43.0) ​ $ 8.9 ​ Total ​ $ (0.4) ​ $ 0.8 ​ $ 0.4 ​ $ 1.4 ​ (1) Amounts do not include the loss of $22.0 million recorded from the change in fair value of the forward currency hedge arrangement on the euro-denominated purchase price of the Arkema PMMA business during the nine months ended September 30, 2021. ​ The Company expects to reclassify in the next twelve months an approximate $2.5 million net loss from AOCI into earnings related to the Company’s outstanding foreign exchange cash flow hedges and interest rate swaps as of September 30, 2021 based on current foreign exchange rates. The following tables summarize the gross and net unrealized gains and losses, as well as the balance sheet classification, of outstanding derivatives recorded in the condensed consolidated balance sheets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ ​ Foreign ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exchange ​ Exchange ​ Interest ​ Cross ​ ​ ​ ​ Balance Sheet ​ Forward ​ Cash Flow ​ Rate ​ Currency ​ ​ ​ Classification Contracts ​ Hedges ​ Swaps ​ Swaps ​ Total ​ Asset Derivatives: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts receivable, net of allowance ​ $ 18.6 ​ $ 0.9 ​ $ — ​ $ 4.2 ​ $ 23.7 ​ Gross derivative asset position ​ ​ 18.6 ​ ​ 0.9 ​ ​ — ​ ​ 4.2 ​ ​ 23.7 ​ Less: Counterparty netting ​ ​ (0.1) ​ ​ — ​ ​ — ​ ​ — ​ ​ (0.1) ​ Net derivative asset position ​ $ 18.5 ​ $ 0.9 ​ $ — ​ $ 4.2 ​ $ 23.6 ​ Liability Derivatives: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts payable ​ $ (0.8) ​ $ — ​ $ (3.4) ​ $ — ​ $ (4.2) ​ Other noncurrent obligations ​ ​ — ​ ​ — ​ ​ — ​ ​ (33.7) ​ ​ (33.7) ​ Gross derivative liability position ​ ​ (0.8) ​ ​ — ​ ​ (3.4) ​ ​ (33.7) ​ ​ (37.9) ​ Less: Counterparty netting ​ ​ 0.1 ​ ​ — ​ ​ — ​ ​ — ​ ​ 0.1 ​ Net derivative liability position ​ $ (0.7) ​ $ — ​ $ (3.4) ​ $ (33.7) ​ $ (37.8) ​ Total net derivative position ​ $ 17.8 ​ $ 0.9 ​ $ (3.4) ​ $ (29.5) ​ $ (14.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Foreign ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ Exchange ​ Exchange ​ Interest ​ Cross ​ ​ ​ ​ Balance Sheet ​ Forward ​ Cash Flow ​ Rate ​ Currency ​ ​ Classification Contracts Hedges Swaps Swaps Total Asset Derivatives: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts receivable, net of allowance (1) ​ $ 8.2 ​ $ — ​ $ — ​ $ 5.0 ​ $ 13.2 ​ Gross derivative asset position ​ ​ 8.2 ​ ​ — ​ ​ — ​ ​ 5.0 ​ ​ 13.2 ​ Less: Counterparty netting ​ ​ (6.5) ​ ​ — ​ ​ — ​ ​ — ​ ​ (6.5) ​ Net derivative asset position ​ $ 1.7 ​ $ — ​ $ — ​ $ 5.0 ​ $ 6.7 ​ Liability Derivatives: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts payable (1) ​ $ (8.3) ​ $ (2.1) ​ $ (3.4) ​ $ — ​ $ (13.8) ​ Other noncurrent obligations ​ ​ — ​ ​ — ​ ​ (2.5) ​ ​ (66.5) ​ ​ (69.0) ​ Gross derivative liability position ​ ​ (8.3) ​ ​ (2.1) ​ ​ (5.9) ​ ​ (66.5) ​ ​ (82.8) ​ Less: Counterparty netting ​ ​ 6.5 ​ ​ — ​ ​ — ​ ​ — ​ ​ 6.5 ​ Net derivative liability position ​ $ (1.8) ​ $ (2.1) ​ $ (5.9) ​ $ (66.5) ​ $ (76.3) ​ Total net derivative position ​ $ (0.1) ​ $ (2.1) ​ $ (5.9) ​ $ (61.5) ​ $ (69.6) ​ (1) Balance as of December 31, 2020 includes a $7.3 million receivable representing the fair value of the forward currency hedge arrangement on the euro-denominated purchase price of the Arkema PMMA business. Forward contracts, interest rate swaps, and cross currency swaps are entered into with a limited number of counterparties, each of which allows for net settlement of all contracts through a single payment in a single currency in the event of a default on or termination of any one contract. As such, in accordance with the Company’s accounting policy, these derivative instruments are recorded on a net basis by counterparty within the condensed consolidated balance sheets. Refer to Notes 11 and 18 of the condensed consolidated financial statements for further information regarding the fair value of the Company’s derivative instruments and the related changes in AOCI.

Fair Value Measurements

Fair Value Measurements9 Months Ended
Sep. 30, 2021
Fair Value Measurements
Fair Value MeasurementsNOTE 11—FAIR VALUE MEASUREMENTS Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Assets and liabilities measured at fair value are classified using the following hierarchy, which is based upon the transparency of inputs to the valuation as of the measurement date. Level 1—Valuation is based upon quoted prices (unadjusted) for identical assets or liabilities in active markets. Level 2—Valuation is based upon quoted prices for similar assets and liabilities in active markets, or other inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the financial instrument. Level 3—Valuation is based upon other unobservable inputs that are significant to the fair value measurement. The following table summarizes the basis used to measure certain assets and liabilities at fair value on a recurring basis in the condensed consolidated balance sheets as of September 30, 2021 and December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ ​ Quoted Prices in Active Markets for Identical Items ​ Significant Other Observable Inputs ​ Significant Unobservable Inputs ​ ​ ​ Assets (Liabilities) at Fair Value (Level 1) (Level 2) (Level 3) Total Foreign exchange forward contracts—Assets $ — $ 18.5 $ — $ 18.5 ​ Foreign exchange forward contracts—(Liabilities) ​ — ​ (0.7) ​ — ​ (0.7) ​ Foreign exchange cash flow hedges—Assets ​ ​ — ​ ​ 0.9 ​ ​ — ​ ​ 0.9 ​ Interest rate swaps—(Liabilities) ​ ​ — ​ ​ (3.4) ​ ​ — ​ ​ (3.4) ​ Cross currency swaps—Assets ​ ​ — ​ ​ 4.2 ​ ​ — ​ ​ 4.2 ​ Cross currency swaps—(Liabilities) ​ ​ — ​ ​ (33.7) ​ ​ — ​ ​ (33.7) ​ Total fair value ​ $ — ​ $ (14.2) ​ $ — ​ $ (14.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Quoted Prices in Active Markets for Identical Items ​ Significant Other Observable Inputs ​ Significant Unobservable Inputs ​ ​ ​ Assets (Liabilities) at Fair Value (Level 1) (Level 2) (Level 3) Total Foreign exchange forward contracts—Assets ​ $ — $ 1.7 $ — $ 1.7 ​ Foreign exchange forward contracts—(Liabilities) ​ ​ — ​ ​ (1.8) ​ ​ — ​ ​ (1.8) ​ Foreign exchange cash flow hedges—(Liabilities) ​ ​ — ​ ​ (2.1) ​ ​ — ​ ​ (2.1) ​ Interest rate swaps—(Liabilities) ​ ​ — ​ ​ (5.9) ​ ​ — ​ ​ (5.9) ​ Cross currency swaps—Assets ​ ​ — ​ ​ 5.0 ​ ​ — ​ ​ 5.0 ​ Cross currency swaps—(Liabilities) ​ ​ — ​ ​ (66.5) ​ ​ — ​ ​ (66.5) ​ Total fair value ​ $ — ​ $ (69.6) ​ $ — ​ $ (69.6) ​ ​ The Company uses an income approach to value its derivative instruments, utilizing discounted cash flow techniques, considering the terms of the contract and observable market information available as of the reporting date, such as interest rate yield curves and currency spot and forward rates. Significant inputs to the valuation for these derivative instruments are obtained from broker quotations or from listed or over-the-counter market data, and are classified as Level 2 in the fair value hierarchy. Nonrecurring Fair Value Measurements The Company measured certain financial assets at fair value on a nonrecurring basis during the year ended December 31, 2020, which were still held as of September 30, 2021. These financial assets represent the Company’s styrene monomer assets in Boehlen, Germany, which it continues to operate. These assets were measured at fair value using underlying fixed asset records in conjunction with the use of industry experience and available market data, which are classified as Level 3 significant unobservable inputs in the fair value hierarchy. As a result of the fair value measurements performed, the Company recorded impairment charges on the Boehlen styrene monomer assets of $10.3 million during the first quarter of 2020. During the three and nine months ended September 30, 2021, the Company recorded additional impairment charges of $0.3 million and $2.1 million related to capital expenditures at the Boehlen styrene monomer facility that it determined to be impaired, which are also included within “Impairment charges” on the condensed consolidated statements of operations. Refer to the Company’s Annual Report for further information. As of September 30, 2021 and December 31, 2020, the value of the Boehlen styrene monomer assets are recorded at $3.5 million and $3.7 million, respectively, within the Company’s condensed consolidated balance sheets herein. The Company’s polybutadiene rubber (“PBR,” specifically nickel and neodymium PBR) assets in Schkopau, Germany, which were mothballed in 2020, had also been measured on a nonrecurring basis during the year ended December 31, 2020, resulting in impairment charges of $28.0 million being recorded during the first quarter of 2020. However, as the Schkopau PBR assets are part of the Synthetic Rubber business, during the second quarter of 2021 they were classified as held-for-sale and their operating results were classified as discontinued operations for all periods presented, along with the rest of the Synthetic Rubber business. Refer to Note 4 for further information. There were no other financial assets or liabilities measured at fair value on a nonrecurring basis as of December 31, 2020. Fair Value of Debt Instruments The following table presents the estimated fair value of the Company’s outstanding debt not carried at fair value as of September 30, 2021 and December 31, 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ As of ​ September 30, 2021 December 31, 2020 2029 Senior Notes ​ $ 455.5 ​ $ — ​ 2028 Term Loan B ​ ​ 742.7 ​ ​ — ​ 2025 Senior Notes ​ ​ 509.7 ​ ​ 513.5 ​ 2024 Term Loan B ​ ​ 670.4 ​ ​ 674.0 ​ Total fair value ​ $ 2,378.3 ​ $ 1,187.5 ​ ​ The fair value of the Company’s debt facilities above (each Level 2 securities) is determined using over-the-counter market quotes and benchmark yields received from independent vendors. The amount outstanding under the Accounts Receivable Securitization Facility of $130.0 million as of September 30, 2021 is short-term in nature and thus the Company estimates the carrying value of the obligation approximates its fair value. There were no other significant financial instruments outstanding as of September 30, 2021 and December 31, 2020.

Provision for Income Taxes

Provision for Income Taxes9 Months Ended
Sep. 30, 2021
Provision for Income Taxes
Income TaxesNOTE 12—PROVISION FOR INCOME TAXES ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2021 2020 2021 2020 ​ Effective income tax rate ​ ​ 6.5 % ​ 40.1 % ​ 14.9 % ​ 126.5 % ​ ​ Provision for income taxes for the three and nine months ended September 30, 2021 totaled $5.5 million and $48.9 million, respectively, resulting in an effective tax rate of 6.5% and 14.9%, respectively. Provision for income taxes for the three and nine months ended September 30, 2020 totaled $26.9 million and $16.2 million, respectively, resulting in an effective tax rate of 40.1% and 126.5%, respectively. The effective income tax rate for the three months ended September 30, 2021 was significantly impacted by the release of a valuation allowance of $16.3 million, as a result of improvements in actual business operations and projected future results of one of the Company’s subsidiaries in China. The effective income tax rate for the three and nine months ended September 30, 2020 was primarily driven by the Company’s overall forecasted jurisdictional mix of earnings, where the tax benefit on losses expected to be generated in lower rate jurisdictions was offset by tax expense on income expected to be generated in higher tax jurisdictions. Also impacting the rate for the nine months ended September 30, 2020 was a tax benefit related to the impairment charges recorded during the period related to the Company’s assets in Boehlen, Germany. Refer to Note 11 in the condensed consolidated financial statements for further information.

Commitments and Contingencies

Commitments and Contingencies9 Months Ended
Sep. 30, 2021
Commitments and Contingencies Disclosure
Commitments and ContingenciesNOTE 13—COMMITMENTS AND CONTINGENCIES Environmental Matters Accruals for environmental matters are recorded when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated based on current law, existing technologies and other information. Pursuant to the terms of the agreement associated with the Company’s formation, the pre-closing environmental liabilities were retained by Dow, and Dow agreed, subject to temporal, monetary, and other limitations to indemnify the Company from and against environmental liabilities incurred or relating to the predecessor periods. Other than certain immaterial environmental liabilities assumed as part of the PMMA Acquisition and the Aristech Surfaces Acquisition, no environmental claims have been asserted or threatened against the Company, and the Company is not a potentially responsible party at any Superfund Sites. As of September 30, 2021 the Company had $5.1 million of accrued obligations for environmental remediation or restoration costs, which were recorded at fair value within the opening balance sheets of the PMMA business and Aristech Surfaces during 2021. The Company had no accrued obligations for environmental remediation or restoration costs as of December 31, 2020. Inherent uncertainties exist in the Company’s potential environmental liabilities primarily due to unknown conditions, whether future claims may fall outside the scope of the indemnity, changing governmental regulations and legal standards regarding liability, and evolving technologies for handling site remediation and restoration. In connection with the Company’s existing indemnification, the possibility is considered remote that environmental remediation costs will have a material adverse impact on the condensed consolidated financial statements over the next 12 months. Purchase Commitments In the normal course of business, the Company has certain raw material purchase contracts where it is required to purchase certain minimum volumes at current market prices. These commitments range from one Litigation Matters From time to time, the Company may be subject to various legal claims and proceedings incidental to the normal conduct of business, relating to such matters as employees, product liability, antitrust/competition, past waste disposal practices and release of chemicals into the environment. While it is impossible at this time to determine with certainty the ultimate outcome of these routine claims, the Company does not believe that the ultimate resolution of these claims will have a material adverse effect on the Company’s results of operations, financial condition or cash flow. Legal costs, including those legal costs expected to be incurred in connection with a loss contingency, are expensed as incurred. European Commission Request for Information On June 6, 2018, Trinseo Europe GmbH, a subsidiary of the Company, received a Request for Information in the form of a letter from the European Commission Directorate General for Competition (the “European Commission”) related to styrene monomer commercial activity in the European Economic Area. The Company subsequently commenced an internal investigation into these commercial activities and discovered instances of inappropriate activity. On October 28, 2019, a supplemental request for information was received from the European Commission. This request was limited to historical employment, entity, and organizational structures, along with certain financial, styrene purchasing, and styrene market information, as well as certain spot styrene purchase contracts. The Company has provided this information and continues to fully cooperate with the European Commission. The proceedings with the European Commission continue and its outcome remains open. Based on its findings, the European Commission may decide to: (i) require further information; (ii) conduct unannounced raids of the Company’s premises; (iii) adopt a decision imposing fines, and/or request certain behavioral or structural commitments from the Company; or (iv) in view of defense arguments by the Company close the proceedings. As a result of the above factors, the Company is unable to predict the ultimate outcome of this matter or estimate the range of reasonably possible losses that could be incurred. However, any potential losses incurred could be material to the Company’s results of operations, balance sheet, and cash flows for the period in which they are resolved or become probable and reasonably estimable.

Pension Plans and Other Postret

Pension Plans and Other Postretirement Benefits9 Months Ended
Sep. 30, 2021
Pension Plans and Other Postretirement Benefits
Pension Plans and Other Postretirement BenefitsNOTE 14—PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS The components of net periodic benefit costs for all significant plans were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2021 2020 2021 2020 Defined Benefit Pension Plans (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service cost ​ $ 4.2 ​ $ 3.3 $ 12.4 ​ $ 9.8 ​ Interest cost ​ 0.4 ​ 0.8 ​ 1.4 ​ 2.2 ​ Expected return on plan assets ​ (0.3) ​ (0.3) ​ (0.6) ​ (0.9) ​ Amortization of prior service credit ​ (0.5) ​ (0.3) ​ (0.9) ​ (0.9) ​ Amortization of net loss ​ 1.6 ​ 1.0 ​ 4.7 ​ 3.1 ​ Settlement and curtailment (gain) loss ​ (2.3) ​ 1.1 ​ (2.3) ​ 1.1 ​ Net periodic benefit cost ​ $ 3.1 ​ $ 5.6 ​ $ 14.7 ​ $ 14.4 ​ (1) All amounts represent components of net periodic benefit costs. The Company had less than $0.1 million of net periodic benefit costs for its other postretirement plans for the three and nine months ended September 30, 2021 and 2020. Service cost related to the Company’s defined benefit pension plans and other postretirement plans is included within “Cost of sales” and “Selling, general and administrative expenses,” whereas all other components of net periodic benefit cost are included within “Other expense (income), net” in the condensed consolidated statements of operations. As of September 30, 2021 and December 31, 2020, the Company’s benefit obligations included primarily in “Other noncurrent obligations” in the condensed consolidated balance sheets were $298.2 million and $294.4 million, respectively. The Company made cash contributions and benefit payments to unfunded plans of approximately $2.6 million and $6.1 million during the three and nine months ended September 30, 2021, respectively. The Company expects to make additional cash contributions, including benefit payments to unfunded plans, of approximately $1.4 million to its defined benefit plans for the remainder of 2021.

Share-Based Compensation

Share-Based Compensation9 Months Ended
Sep. 30, 2021
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based CompensationNOTE 15—SHARE-BASED COMPENSATION Refer to the Annual Report for definitions of capitalized terms not included herein and further background on the Company’s share-based compensation programs included in the tables below. The following table summarizes the Company’s share-based compensation expense for the three and nine months ended September 30, 2021 and 2020, as well as unrecognized compensation cost as of September 30, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ September 30, 2021 ​ ​ ​ September 30, ​ September 30, ​ Unrecognized ​ Weighted ​ ​ 2021 2020 2021 2020 Compensation Cost Average Years ​ RSUs ​ $ 2.1 ​ $ 1.5 ​ $ 5.7 ​ $ 4.9 ​ $ 13.60 ​ 2.0 ​ Options ​ ​ 1.2 ​ ​ 0.6 ​ ​ 3.5 ​ ​ 2.3 ​ ​ 4.60 ​ 1.5 ​ PSUs ​ ​ 0.7 ​ ​ 0.5 ​ ​ 1.8 ​ ​ 1.5 ​ ​ 3.70 ​ 1.9 ​ Total share-based compensation expense ​ $ 4.0 ​ $ 2.6 ​ $ 11.0 ​ $ 8.7 ​ ​ ​ ​ ​ ​ ​ The following table summarizes awards granted and the respective weighted average grant date fair value for the nine months ended September 30, 2021: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ ​ ​ September 30, 2021 ​ ​ ​ Awards Granted ​ Weighted Average Grant Date Fair Value per Award ​ RSUs ​ ​ 212,167 ​ $ 58.59 ​ Options ​ ​ 296,354 ​ ​ 22.61 ​ PSUs ​ ​ 49,463 ​ ​ 61.06 ​ ​ Option Awards The following are the weighted average assumptions used within the Black-Scholes pricing model for the Company’s option awards granted during the nine months ended September 30, 2021: ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ ​ September 30, 2021 ​ Expected term (in years) 5.50 ​ Expected volatility 48.69 % Risk-free interest rate 0.78 % Dividend yield ​ 1.81 % ​ The expected volatility assumption is determined based on the historical volatility of the Company’s publicly traded ordinary shares. The expected term of option awards represents the period of time that option awards granted are expected to be outstanding. For the option awards granted during the nine months ended September 30, 2021, the simplified method was used to calculate the expected term, given the Company’s limited historical exercise data. The risk-free interest rate for the periods within the expected term of option awards is based on the U.S. Treasury yield curve in effect at the time of grant. The dividend yield is estimated based on historical and expected dividend activity. Performance Share Units (PSUs) The following are the weighted average assumptions used within the Monte Carlo valuation model for PSUs granted during the nine months ended September 30, 2021: ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ ​ ​ September 30, 2021 ​ Expected term (in years) ​ 3.00 ​ Expected volatility 58.00 % Risk-free interest rate 0.20 % Share price $ 61.06 ​ ​ Determining the fair value of PSUs requires considerable judgment, including estimating the expected volatility of the price of the Company’s ordinary shares, the correlation between the Company’s share price and that of its peer companies, and the expected rate of interest. The expected volatility for each grant is determined based on the historical volatility of the Company’s ordinary shares. The expected term of PSUs represents the length of the performance period. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for a duration equivalent to the performance period. The share price is the closing price of the Company’s ordinary shares on the grant date.

Segments

Segments9 Months Ended
Sep. 30, 2021
Segments
SegmentsNOTE 16—SEGMENTS Beginning in the second quarter of 2021, the Company reported the results of the Synthetic Rubber business as discontinued operations in the condensed consolidated statements of operations for all periods presented, and therefore it is no longer presented as a separate reportable segment. Refer to Note 4 for further information. Additionally, as discussed in the Annual Report, the Company realigned its reporting segments effective October 1, 2020, as a result of which the Company’s former Performance Plastics segment was reorganized into two standalone reporting segments: Engineered Materials and Base Plastics. There were no changes to the Company’s remaining four segments. Refer to the Annual Report for further information on the resegmentation. The information in the tables below has been retroactively adjusted to reflect these changes in reporting segments . The Latex Binders segment produces styrene-butadiene latex (“SB latex”) and other latex polymers and binders, primarily for coated paper and packaging board, carpet and artificial turf backings, as well as a number of performance latex binders applications, such as adhesive, building and construction and the technical textile paper market. The Engineered Materials segment includes the Company’s compounds and blends products sold into higher growth and value applications, such as consumer electronics and medical, as well as soft thermoplastic elastomers (“TPEs”) products which are sold into markets such as footwear and automotive. Additionally, PMMA and MMA products, which are sold into a variety of applications including automotive, building & construction, medical, consumer electronics, and wellness, among others. The Base Plastics segment contains the results of the acrylonitrile-butadiene-styrene (“ABS”), styrene-acrylonitrile (“SAN”), and polycarbonate (“PC”) businesses, as well as compounds and blends for automotive and other applications. The Polystyrene segment includes a variety of general purpose polystyrenes (“GPPS”) and polystyrene that has been modified with polybutadiene rubber to increase its impact resistant properties (“HIPS”). The Feedstocks segment includes the Company’s production and procurement of styrene monomer outside of North America, which is used as a key raw material in many of the Company’s products, including polystyrene, SB latex, and ABS resins. Lastly, the Americas Styrenics segment consists solely of the operations of the Company’s The following table provides disclosure of the Company’s segment Adjusted EBITDA, which is used to measure segment operating performance and is defined below, for the three and nine months ended September 30, 2021 and 2020. Asset and intersegment sales information by reporting segment is not regularly reviewed or included with the Company’s reporting to the chief operating decision maker. Therefore, this information has not been disclosed below. Refer to Note 5 for the Company’s net sales to external customers by segment for the three and nine months ended September 30, 2021 and 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Latex ​ Engineered ​ Base ​ ​ ​ ​ ​ Americas Three Months Ended (1) ​ Binders ​ Materials ​ Plastics ​ Polystyrene ​ Feedstocks ​ Styrenics September 30, 2021 $ 37.1 $ 32.7 ​ $ 87.9 ​ $ 51.2 $ (27.6) $ 17.1 ​ September 30, 2020 ​ $ 18.7 ​ $ 9.4 ​ $ 40.5 ​ $ 20.4 ​ $ 10.1 ​ $ 18.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Latex ​ Engineered ​ Base ​ ​ ​ ​ ​ Americas Nine Months Ended (1) ​ Binders ​ Materials ​ Plastics ​ Polystyrene ​ Feedstocks ​ Styrenics September 30, 2021 ​ $ 86.2 ​ $ 68.5 ​ $ 235.0 ​ $ 149.6 ​ $ 58.5 ​ $ 70.2 ​ September 30, 2020 ​ $ 55.4 ​ $ 22.3 ​ $ 55.6 ​ $ 46.4 ​ $ (10.6) ​ $ 42.5 ​ (1) The Company’s primary measure of segment operating performance is Adjusted EBITDA, which is defined as income from continuing operations before interest expense, net; provision for income taxes; depreciation and amortization expense; loss on extinguishment of long-term debt; asset impairment charges; gains or losses on the dispositions of businesses and assets; restructuring charges; acquisition related costs and benefits and other items. Segment Adjusted EBITDA is a key metric that is used by management to evaluate business performance in comparison to budgets, forecasts, and prior year financial results, providing a measure that management believes reflects core operating performance by removing the impact of transactions and events that would not be considered a part of core operations. Other companies in the industry may define segment Adjusted EBITDA differently than the Company, and as a result, it may be difficult to use segment Adjusted EBITDA, or similarly named financial measures, that other companies may use to compare the performance of those companies to the Company’s segment performance. ​ The reconciliation of income from continuing operations before income taxes to segment Adjusted EBITDA is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2021 2020 2021 2020 Income from continuing operations before income taxes ​ $ 84.9 ​ $ 67.1 ​ $ 327.1 ​ $ 12.8 ​ Interest expense, net ​ 23.0 ​ 10.0 ​ 56.6 ​ 32.0 ​ Depreciation and amortization ​ 49.8 ​ 21.2 ​ ​ 111.0 ​ 69.8 ​ Corporate Unallocated (2) ​ ​ 25.0 ​ ​ 16.6 ​ ​ 71.3 ​ ​ 56.1 ​ Adjusted EBITDA Addbacks (3) ​ 15.7 ​ 2.5 ​ 102.0 ​ 40.9 ​ Segment Adjusted EBITDA ​ $ 198.4 ​ $ 117.4 ​ $ 668.0 ​ $ 211.6 ​ (2) Corporate unallocated includes corporate overhead costs and certain other income and expenses. (3) Adjusted EBITDA addbacks for the three and nine months ended September 30, 2021 and 2020 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2021 2020 2021 2020 Net gain on disposition of businesses and assets ​ $ — ​ $ — ​ $ (0.2) ​ $ (0.4) ​ Restructuring and other charges (Note 17) ​ ​ 0.2 ​ ​ (0.1) ​ ​ 6.8 ​ ​ 7.0 ​ Acquisition transaction and integration net costs (a) ​ ​ 13.6 ​ ​ — ​ ​ 62.8 ​ ​ (0.3) ​ Acquisition purchase price hedge loss (Note 10) ​ ​ — ​ ​ — ​ ​ 22.0 ​ ​ — ​ Asset impairment charges or write-offs (Note 11) ​ ​ 1.2 ​ ​ — ​ ​ 3.0 ​ ​ 10.3 ​ Other items (b) ​ ​ 0.7 ​ ​ 2.6 ​ ​ 7.6 ​ ​ 24.3 ​ Total Adjusted EBITDA Addbacks ​ $ 15.7 ​ $ 2.5 ​ $ 102.0 ​ $ 40.9 ​ (a) Amounts for the three months ended September 30, 2021 include $10.1 million of total acquisition and integration costs and $3.5 million related to amortization of the fair-value step-up to inventory associated with the Aristech Surfaces Acquisition. Amounts for the nine months ended September 30, 2021 include $44.7 million of total acquisition and integration costs, $13.6 million related to amortization of the fair-value step-up to inventory associated with acquisitions, and $4.5 million of transfer taxes associated with the PMMA Acquisition. Refer to Note 3 for further information (b) Other items for the three and nine months ended September 30, 2021 primarily relate to fees incurred in conjunction with certain of the Company’s strategic initiatives, including the ERP upgrade project. Other items for the three and nine months ended September 30, 2020 primarily relate to advisory and professional fees incurred in conjunction with the Company’s initiative to transition business services from Dow, including certain administrative services such as accounts payable, logistics, and IT services, which was substantially completed in 2020, as well as fees incurred in conjunction with certain of the Company’s strategic initiatives.

Restructuring

Restructuring9 Months Ended
Sep. 30, 2021
Restructuring
RestructuringNOTE 17—RESTRUCTURING Refer to the Annual Report for further details regarding the Company’s previously announced restructuring activities included in the tables below. Restructuring charges are included within “Selling, general and administrative expenses” in the condensed consolidated statements of operations. The following table provides detail of the Company’s restructuring charges for the three and nine months ended September 30, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ Cumulative ​ ​ ​ ​ ​ September 30, ​ September 30, ​ Life-to-date ​ ​ ​ ​ ​ 2021 2020 ​ 2021 2020 ​ Charges Segment ​ Corporate Restructuring Program ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accelerated depreciation ​ $ — ​ $ — ​ $ (0.4) ​ $ 2.5 ​ $ 2.5 ​ ​ ​ Employee termination benefits ​ ​ (0.1) ​ ​ (0.5) ​ ​ 0.4 ​ ​ 3.9 ​ ​ 19.9 ​ ​ ​ Contract terminations ​ ​ — ​ ​ — ​ ​ — ​ ​ 2.4 ​ ​ 2.8 ​ ​ ​ Decommissioning and other ​ ​ — ​ ​ 0.2 ​ ​ — ​ ​ 0.2 ​ ​ 0.2 ​ ​ ​ Corporate Program Subtotal ​ $ (0.1) ​ $ (0.3) ​ $ — ​ $ 9.0 ​ $ 25.4 ​ N/A (1) ​ Transformational Restructuring Program ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Employee termination benefits ​ $ 0.3 ​ $ — ​ $ 6.4 ​ $ — ​ $ 6.4 ​ N/A (2) ​ Transformational Program Subtotal ​ $ 0.3 ​ $ — ​ $ 6.4 ​ $ — ​ $ 6.4 ​ ​ ​ Other Restructurings ​ ​ — ​ ​ 0.2 ​ ​ — ​ ​ 0.5 ​ ​ ​ ​ Various ​ Total Restructuring Charges ​ $ 0.2 ​ $ (0.1) ​ $ 6.4 ​ $ 9.5 ​ ​ ​ ​ ​ ​ (1) In November 2019, the Company announced a corporate restructuring program associated with the Company’s shift to a global functional structure and business excellence initiatives to drive greater focus on business process optimization and efficiency, which continued through the three and nine months ended September 30, 2021. The Company expects to incur a limited amount of incremental employee termination benefit charges through the end of 2021, and the majority of these benefits are expected to be paid by the end of 2021. As this was identified as a corporate-related activity, the charges related to this restructuring program were not allocated to a specific segment, but rather included within corporate unallocated. (2) In May 2021, the Company approved a transformational restructuring program associated with the Company’s recent strategic initiatives. In connection with this restructuring program, during the three and nine months ended September 30, 2021, the Company incurred employee termination benefits charges of $0.3 million and $6.4 million, respectively. The Company expects to incur incremental employee termination benefit charges related to impacted employees as of September 30, 2021 of less than $1.0 million, the majority of which are expected to be paid by June 30, 2022. As this was identified as a corporate-related activity, the charges related to this restructuring program were not allocated to a specific segment, but rather included within corporate unallocated. The following table provides a roll forward of the liability balances associated with the Company’s restructuring activities as of September 30, 2021. Employee termination benefit and contract termination charges are primarily recorded within “Accrued expenses and other current liabilities” in the condensed consolidated balance sheets. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ ​ ​ Balance at ​ December 31, 2020 Expenses Deductions (1) September 30, 2021 Employee termination benefits ​ $ 7.9 ​ $ 6.8 ​ $ (5.4) ​ $ 9.3 ​ Contract terminations ​ ​ 0.1 ​ ​ — ​ ​ (0.1) ​ ​ — ​ Total ​ $ 8.0 ​ $ 6.8 ​ $ (5.5) ​ $ 9.3 ​ (1) Primarily includes payments made against the existing accrual, as well as immaterial impacts of foreign currency remeasurement.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income9 Months Ended
Sep. 30, 2021
Shareholders' Equity.
Accumulated Other Comprehensive Income (Loss)NOTE 18—ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) The components of AOCI, net of income taxes, consisted of: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cumulative Pension & Other ​ ​ ​ ​ ​ ​ ​ ​ Translation ​ Postretirement Benefit ​ ​ Cash Flow ​ ​ ​ ​ Three Months Ended September 30, 2021 and 2020 Adjustments Plans, Net ​ Hedges, Net Total Balance as of June 30, 2021 ​ $ (109.3) ​ $ (69.8) ​ $ (0.8) ​ $ (179.9) ​ Other comprehensive income (loss) ​ (1.7) ​ 9.3 ​ 0.6 ​ 8.2 ​ Amounts reclassified from AOCI to net income (1) ​ ​ — ​ ​ (1.2) ​ ​ 0.6 ​ ​ (0.6) ​ Balance as of September 30, 2021 ​ $ (111.0) ​ $ (61.7) ​ $ 0.4 ​ $ (172.3) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance as of June 30, 2020 ​ $ (97.1) ​ $ (54.6) ​ $ (4.4) ​ $ (156.1) ​ Other comprehensive income (loss) ​ (6.7) ​ 0.1 ​ (1.1) ​ (7.7) ​ Amounts reclassified from AOCI to net income (1) ​ ​ — ​ ​ 1.6 ​ ​ 1.5 ​ ​ 3.1 ​ Balance as of September 30, 2020 ​ $ (103.8) ​ $ (52.9) ​ $ (4.0) ​ $ (160.7) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cumulative Pension & Other ​ ​ ​ ​ ​ ​ ​ Translation ​ Postretirement Benefit ​ Cash Flow ​ ​ ​ ​ Nine Months Ended September 30, 2021 and 2020 ​ Adjustments Plans, Net Hedges, Net Total ​ Balance as of December 31, 2020 ​ $ (109.0) ​ $ (71.9) ​ $ (5.2) ​ $ (186.1) ​ Other comprehensive income (loss) ​ (2.0) ​ 9.3 ​ 3.0 ​ 10.3 ​ Amounts reclassified from AOCI to net income (1) ​ ​ — ​ ​ 0.9 ​ ​ 2.6 ​ ​ 3.5 ​ Balance as of September 30, 2021 ​ $ (111.0) ​ $ (61.7) ​ $ 0.4 ​ $ (172.3) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance as of December 31, 2019 ​ $ (106.7) ​ $ (56.3) ​ $ 0.6 ​ $ (162.4) ​ Other comprehensive income (loss) ​ 2.9 ​ 0.7 ​ (6.2) ​ (2.6) ​ Amounts reclassified from AOCI to net loss (1) ​ ​ — ​ ​ 2.7 ​ ​ 1.6 ​ ​ 4.3 ​ Balance as of September 30, 2020 ​ $ (103.8) ​ $ (52.9) ​ $ (4.0) ​ $ (160.7) ​ (1) The following is a summary of amounts reclassified from AOCI to net income (loss) for the three and nine months ended September 30, 2021 and 2020: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ ​ ​ September 30, ​ September 30, ​ Statements of Operations ​ AOCI Components 2021 2020 2021 2020 Classification ​ Cash flow hedging items ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange cash flow hedges ​ $ (0.3) ​ $ 0.7 ​ $ — ​ $ — ​ Cost of sales ​ Interest rate swaps ​ ​ 0.9 ​ ​ 0.8 ​ ​ 2.6 ​ ​ 1.6 ​ Interest expense, net ​ Total before tax ​ ​ 0.6 ​ ​ 1.5 ​ ​ 2.6 ​ ​ 1.6 ​ ​ ​ Tax effect ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ Provision for income taxes ​ Total, net of tax ​ $ 0.6 ​ $ 1.5 ​ $ 2.6 ​ $ 1.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of pension and other postretirement benefit plan items ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Prior service credit ​ $ (0.2) ​ $ (0.3) ​ $ (0.7) ​ $ (0.9) ​ (a) ​ Net actuarial loss ​ ​ 1.7 ​ ​ 1.2 ​ ​ 5.3 ​ ​ 3.5 ​ (a) ​ Net curtailment and settlement (gain) loss ​ ​ (2.5) ​ ​ 1.1 ​ ​ (2.5) ​ ​ 1.1 ​ (a) ​ Total before tax ​ ​ (1.0) ​ ​ 2.0 ​ ​ 2.1 ​ ​ 3.7 ​ ​ ​ Tax effect ​ ​ (0.2) ​ ​ (0.4) ​ ​ (1.2) ​ ​ (1.0) ​ Provision for income taxes ​ Total, net of tax ​ $ (1.2) ​ $ 1.6 ​ $ 0.9 ​ $ 2.7 ​ ​ ​ (a) These AOCI components are included in the computation of net periodic benefit costs (see Note 14). .

Earnings Per Share

Earnings Per Share9 Months Ended
Sep. 30, 2021
Earnings Per Share
Earnings Per ShareNOTE 19—EARNINGS PER SHARE Basic earnings per ordinary share (“basic EPS”) is computed by dividing net income available to ordinary shareholders by the weighted average number of the Company’s ordinary shares outstanding for the applicable period. Diluted earnings per ordinary share (“diluted EPS”) is calculated using net income available to ordinary shareholders divided by diluted weighted average ordinary shares outstanding during each period, which includes unvested RSUs, option awards, and PSUs. Diluted EPS considers the impact of potentially dilutive securities except in periods in which there is a loss from continuing operations because the inclusion of the potential ordinary shares would have an anti-dilutive effect. The following table presents basic EPS and diluted EPS for the three and nine months ended September 30, 2021 and 2020. Amounts have been recast to reflect the Company’s classification of its Synthetic Rubber business as discontinued operations for all periods presented. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ (in millions, except per share data) 2021 2020 2021 2020 Earnings: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) from continuing operations ​ $ 79.4 ​ $ 40.2 ​ $ 278.2 ​ $ (3.4) ​ Net income (loss) from discontinued operations ​ ​ 13.7 ​ ​ 65.6 ​ ​ 38.0 ​ ​ (55.4) ​ Net income (loss) ​ $ 93.1 ​ $ 105.8 ​ $ 316.2 ​ $ (58.8) ​ Shares: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average ordinary shares outstanding ​ 38.8 ​ 38.3 ​ 38.7 ​ 38.4 ​ Dilutive effect of RSUs, option awards, and PSUs (1) ​ 0.7 ​ 0.1 ​ 0.9 ​ — ​ Diluted weighted average ordinary shares outstanding ​ 39.5 ​ 38.4 ​ 39.6 ​ 38.4 ​ Income (loss) per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income (loss) per share—basic: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Continuing operations ​ ​ 2.04 ​ ​ 1.05 ​ ​ 7.19 ​ ​ (0.09) ​ Discontinued operations ​ ​ 0.35 ​ ​ 1.72 ​ ​ 0.98 ​ ​ (1.44) ​ Income (loss) per share—basic ​ $ 2.39 ​ $ 2.77 ​ $ 8.17 ​ $ (1.53) ​ Income (loss) per share—diluted: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Continuing operations ​ ​ 2.01 ​ ​ 1.04 ​ ​ 7.03 ​ ​ (0.09) ​ Discontinued operations ​ ​ 0.35 ​ ​ 1.71 ​ ​ 0.96 ​ ​ (1.44) ​ Income (loss) per share—diluted ​ $ 2.36 ​ $ 2.75 ​ $ 7.99 ​ $ (1.53) ​ (1) Refer to Note 15 for discussion of RSUs, option awards, and PSUs granted to certain Company directors and employees. There were 0.6 million anti-dilutive shares that have been excluded from the computation of diluted earnings per share for the three and nine months ended September 30, 2021. There were 1.6 million anti-dilutive shares that have been excluded from the computation of diluted earnings per share for the three months ended September 30, 2020. As the Company recorded a net loss from continuing operations for the nine months ended September 30, 2020, potential shares related to equity-based awards have been excluded from the calculation of diluted EPS, as doing so would be anti-dilutive. ​

Basis of Presentation (Policies

Basis of Presentation (Policies)9 Months Ended
Sep. 30, 2021
Basis of Presentation
Basis of PresentationThe unaudited interim condensed consolidated financial statements of Trinseo PLC and its subsidiaries (the “Company”) as of and for the periods ended September 30, 2021 and 2020 were prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) and reflect all adjustments, consisting only of normal recurring adjustments, which, in the opinion of management, are considered necessary for the fair statement of the results for the periods presented. Because they cover interim periods, the statements and related notes to the financial statements do not include all disclosures normally provided in annual financial statements, and therefore, these statements should be read in conjunction with the 2020 audited consolidated financial statements included within the Company’s Annual Report on Form 10-K (“Annual Report”) filed with the Securities and Exchange Commission (“SEC”) on February 22, 2021. The Company’s condensed consolidated financial statements presented herein reflect the latest estimates and assumptions made by management that affect the reported amounts and related disclosures as of and for the period ended September 30, 2021. However, actual results could differ from these estimates and assumptions. On October 8, 2021, the Company completed a cross-border merger transaction, pursuant to which its former publicly-traded parent entity, Trinseo S.A., a Luxembourg limited liability company, was merged with and into Trinseo PLC, an Irish public limited company, with Trinseo PLC as the surviving entity (the “Redomiciliation”). The Redomiciliation was completed pursuant to an agreement between the parties entitled the Common Draft Terms of Merger dated as of April 23, 2021 and was approved by shareholders at Trinseo S.A.’s 2021 annual general meeting on June 14, 2021. As a result of the Redomiciliation, all of Trinseo S.A.’s outstanding ordinary shares, par value $0.01 per share, excluding treasury shares, were exchanged on a one-for-one basis for newly issued ordinary shares, par value $0.01 per share, of Trinseo PLC. The treasury shares of Trinseo S.A. were cancelled in conjunction with the Redomiciliation. All references herein to “Trinseo” or the “Company” refer to Trinseo S.A. and its subsidiaries through the effective date of the Redomiciliation, and thereafter refer to Trinseo PLC and its subsidiaries. As the Redomiciliation was completed subsequent to September 30, 2021, amounts presented herein represent the results of Trinseo S.A. as of and for the periods ended September 30, 2021 and have not been adjusted for the equity transactions completed in connection with the Redomiciliation on October 8, 2021. The December 31, 2020 condensed consolidated balance sheet data presented herein was derived from the Company’s December 31, 2020 audited consolidated financial statements, but does not include all disclosures required by GAAP for annual periods.
ReclassificationsCertain prior year amounts have been reclassified to conform to the current year presentation. These reclassifications pertain primarily to the Company’s entry into an agreement during the second quarter of 2021 to sell its Synthetic Rubber business, as a result of which the Company reclassified its Synthetic Rubber assets and liabilities as held-for-sale and reclassified the operating results of its Synthetic Rubber business, net of taxes, as discontinued operations for all periods presented. Refer to Note 4 for further information. Throughout this Quarterly Report, unless otherwise indicated, amounts and activity are presented on a continuing operations basis. Additionally, the condensed consolidated financial statements herein reflect reclassifications related to the Company’s resegmentation effective October 1, 2020, as described in Note 16.

Acquisitions (Tables)

Acquisitions (Tables)9 Months Ended
Sep. 30, 2021
Business Acquisition [Line Items]
Schedule of unaudited pro forma financial information​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2021 2020 2021 2020 Net sales $ 1,300.2 $ 862.0 $ 3,863.8 $ 2,499.7 Net income (loss) ​ $ 94.1 ​ $ 104.0 ​ $ 355.1 ​ $ (96.7) Income (loss) from continuing operations ​ $ 80.4 ​ $ 38.4 ​ $ 317.1 ​ $ (41.3) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Arkema
Business Acquisition [Line Items]
Schedule of components of the consideration paid​ ​ ​ ​ ​ ​ ​ Initial cash purchase price paid (1) $ 1,369.0 Known purchase price adjustment, not yet settled (2) ​ (4.1) Total purchase price consideration ​ $ 1,364.9 (1) The PMMA Acquisition had an initial purchase price consideration of $1,370.7 million, of which $1,369.0 million was paid during the second quarter of 2021. This initial purchase price consideration remains subject to customary working capital and other closing adjustments. (2) Known purchase price adjustment not yet paid relates primarily to consideration for estimated working capital adjustments and certain assets at the Porto Marghera, Italy manufacturing site which will be legally transferred to Trinseo at a later date due to local transfer restrictions; however, the Company has the benefits and risks of ownership during the period from May 3, 2021 until the site legally transfers. This purchase price consideration is expected to be paid in the fourth quarter of 2021.
Schedule of purchase price allocation​ ​ ​ ​ ​ ​ ​ May 3, ​ 2021 Cash and cash equivalents ​ $ 10.4 Accounts receivable ​ 19.1 Inventories (1) ​ 78.9 Other current assets ​ 8.7 Property, plant and equipment ​ 255.4 Other intangible assets (2) ​ ​ ​ Customer relationships ​ 326.6 Developed technology ​ 133.0 Tradenames ​ ​ 46.0 Other amortizable intangible assets ​ ​ 0.4 Right-of-use assets - operating ​ 4.1 Deferred charges and other assets ​ ​ 27.9 Total fair value of assets acquired ​ ​ 910.5 ​ ​ ​ ​ Accounts payable ​ ​ (15.0) Current lease liabilities - operating ​ (1.7) Income taxes payable ​ ​ (0.3) Accrued expenses and other current liabilities ​ ​ (11.3) Noncurrent lease liabilities - operating ​ ​ (2.5) Deferred income tax liabilities ​ ​ (39.3) Other noncurrent obligations (3) ​ ​ (23.1) Total fair value of liabilities assumed ​ ​ (93.2) Net identifiable assets acquired ​ ​ 817.3 Purchase price consideration ​ ​ 1,364.9 Goodwill (4) ​ $ 547.6 (1) Fair value of finished goods inventory acquired included a step-up in the value of approximately $10.1 million, which was fully amortized during the second quarter of 2021 within "Cost of sales" on the condensed consolidated statements of operations as the related inventory was sold to customers. (2) The expected weighted average useful life of the acquired intangible assets are 13 years for customer relationships, 10 years for developed technology, 16 years for tradenames, and 1 - 5 years for other amortizable intangible assets. (3) Includes $18.2 million of net pension and other employee benefits assumed as part of the PMMA Acquisition. (4) Goodwill largely consists of strategic and synergistic opportunities resulting from combining the PMMA business with the Company’s existing businesses and is allocated entirely to the Engineered Materials segment. Approximately $310.0 million of goodwill related to this acquisition will be deductible for income tax purposes based on the preliminary purchase price.
Aristech Surfaces L L C [Member]
Business Acquisition [Line Items]
Schedule of purchase price allocation​ ​ ​ ​ ​ ​ ​ ​ September 1, ​ ​ 2021 ​ Cash and cash equivalents ​ $ 1.7 ​ Accounts receivable ​ 26.9 ​ Inventories (1) ​ 30.3 ​ Other current assets ​ 1.9 ​ Property, plant and equipment ​ 75.3 ​ Other intangible assets (2) ​ ​ ​ ​ Customer relationships ​ 145.0 ​ Developed technology ​ 52.5 ​ Tradenames ​ ​ 10.0 ​ Other amortizable intangible assets ​ ​ 0.3 ​ Right-of-use assets - operating ​ 2.0 ​ Deferred charges and other assets ​ ​ 0.8 ​ Total fair value of assets acquired ​ ​ 346.7 ​ ​ ​ ​ ​ ​ Accounts payable ​ ​ (13.8) ​ Current lease liabilities - operating ​ (0.4) ​ Accrued expenses and other current liabilities ​ ​ (3.1) ​ Noncurrent lease liabilities - operating ​ ​ (1.6) ​ Other noncurrent obligations ​ ​ (1.4) ​ Total fair value of liabilities assumed ​ ​ (20.3) ​ Net identifiable assets acquired ​ ​ 326.4 ​ Purchase price consideration ​ ​ 449.7 ​ Goodwill (3) ​ $ 123.3 ​ (1) Fair value of work-in-process and finished goods inventory acquired included a step-up in the value of approximately $6.9 million, out of which $3.5 million was amortized during the third quarter of 2021 within "Cost of sales" on the condensed consolidated statements of operations as the related inventory was sold to customers. (2) The expected weighted average useful life of the acquired intangible assets are 13 years for customer relationships, 11 years for developed technology, and 10 years for tradenames and 1 - 5 years for other amortizable intangible assets. (3) Goodwill largely consists of strategic and synergistic opportunities resulting from combining Aristech Surfaces with the Company’s existing businesses and is allocated entirely to the Engineered Materials segment. All of the goodwill related to this acquisition will be deductible for income tax purposes.

Divestitures and Discontinued_2

Divestitures and Discontinued Operations (Tables)9 Months Ended
Sep. 30, 2021
Emulsion Polymers, Synthetic Rubber [Member] | Discontinued Operations, Held-for-sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Summary of the assets and liabilities classified as held-for-sale and results reflected as discontinued operations​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ ​ 2021 ​ 2020 ​ Assets ​ ​ ​ ​ ​ Current assets ​ ​ ​ ​ ​ ​ ​ Accounts receivable, net of allowance ​ $ 83.5 ​ $ 59.7 ​ Inventories and other current assets ​ 89.2 ​ 60.6 ​ Total current assets ​ 172.7 ​ 120.3 ​ Property, plant and equipment, net ​ ​ 152.3 ​ ​ 170.3 ​ Other assets ​ ​ ​ ​ ​ ​ ​ Goodwill ​ 11.4 ​ 12.1 ​ Other intangible assets, net ​ 17.5 ​ 20.2 ​ Deferred charges and other assets ​ 25.6 ​ 25.6 ​ Total other assets ​ 54.5 ​ 57.9 ​ Total assets held-for-sale (1) ​ $ 379.5 ​ $ 348.5 ​ Liabilities ​ ​ ​ ​ ​ ​ ​ Current liabilities ​ ​ ​ ​ ​ ​ ​ Accounts payable ​ 27.6 ​ 29.5 ​ Accrued expenses and other current liabilities ​ ​ 11.3 ​ ​ 12.7 ​ Total current liabilities ​ 38.9 ​ 42.2 ​ Noncurrent liabilities ​ ​ ​ ​ ​ ​ ​ Other noncurrent obligations ​ 42.4 ​ 42.3 ​ Total noncurrent liabilities ​ 42.4 ​ 42.3 ​ Total liabilities held-for-sale (1) ​ $ 81.3 ​ $ 84.5 ​ (1) All balance sheet amounts as of September 30, 2021 have been classified as current within the condensed consolidated balance sheets, as the sale is expected to occur within one year of the balance sheet date. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ 2021 2020 2021 2020 Net sales $ 122.3 $ 79.5 $ 382.2 $ 217.5 Cost of sales ​ 101.9 ​ 82.5 ​ 321.2 ​ 238.9 Gross profit (loss) ​ 20.4 ​ (3.0) ​ 61.0 ​ (21.4) Selling, general and administrative expenses ​ 4.9 ​ 7.4 ​ 16.7 ​ 17.8 Impairment charges ​ ​ — ​ ​ — ​ ​ — ​ ​ 28.0 Operating income (loss) ​ 15.5 ​ (10.4) ​ 44.3 ​ (67.2) Other expense, net ​ ​ 0.2 ​ ​ 0.4 ​ ​ 1.2 ​ ​ 1.1 Income (loss) from discontinued operations before income taxes ​ 15.3 ​ (10.8) ​ 43.1 ​ (68.3) Provision for (benefit from) income taxes ​ 1.6 ​ (76.4) ​ 5.1 ​ (12.9) Net income (loss) from discontinued operations ​ $ 13.7 ​ $ 65.6 ​ $ 38.0 ​ $ (55.4)

Net Sales (Tables)

Net Sales (Tables)9 Months Ended
Sep. 30, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue [Table Text Block]​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Latex ​ Engineered ​ Base ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Binders ​ Materials ​ Plastics ​ Polystyrene ​ Feedstocks ​ Total September 30, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ United States ​ $ 86.3 ​ $ 102.4 ​ $ 82.3 ​ $ — ​ $ 4.0 ​ $ 275.0 ​ Europe ​ 153.5 ​ 89.6 ​ 247.3 ​ 162.6 ​ 50.8 ​ 703.8 ​ Asia-Pacific ​ 73.0 ​ 35.9 ​ 43.9 ​ 112.2 ​ — ​ 265.0 ​ Rest of World ​ 2.8 ​ 2.9 ​ 19.8 ​ — ​ — ​ 25.5 ​ Total ​ $ 315.6 ​ $ 230.8 ​ $ 393.3 ​ $ 274.8 ​ $ 54.8 ​ $ 1,269.3 ​ September 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ United States ​ $ 54.1 ​ $ 8.0 ​ $ 52.8 ​ $ — ​ $ 2.0 ​ $ 116.9 ​ Europe ​ 79.7 ​ 13.8 ​ ​ 126.8 ​ 96.9 ​ 31.7 ​ 348.9 ​ Asia-Pacific ​ 48.1 ​ 28.1 ​ ​ 40.9 ​ 70.4 ​ 4.9 ​ ​ 192.4 ​ Rest of World ​ 1.3 ​ 0.1 ​ ​ 19.6 ​ — ​ — ​ 21.0 ​ Total ​ $ 183.2 ​ $ 50.0 ​ $ 240.1 ​ $ 167.3 ​ $ 38.6 ​ $ 679.2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Latex ​ Engineered ​ Base ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ Binders ​ Materials ​ Plastics ​ Polystyrene ​ Feedstocks ​ Total September 30, 2021 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ United States ​ $ 228.2 ​ $ 174.1 ​ $ 216.5 ​ $ — ​ $ 10.7 ​ $ 629.5 ​ Europe ​ 431.4 ​ 190.8 ​ 699.2 ​ 511.7 ​ 188.9 ​ 2,022.0 ​ Asia-Pacific ​ 211.1 ​ 108.1 ​ 144.5 ​ 343.3 ​ — ​ 807.0 ​ Rest of World ​ 6.9 ​ 4.5 ​ 59.1 ​ — ​ — ​ 70.5 ​ Total ​ $ 877.6 ​ $ 477.5 ​ $ 1,119.3 ​ $ 855.0 ​ $ 199.6 ​ $ 3,529.0 ​ September 30, 2020 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ United States ​ $ 167.2 ​ $ 25.3 ​ $ 143.5 ​ $ — ​ $ 5.9 ​ $ 341.9 ​ Europe ​ 254.0 ​ 37.4 ​ ​ 366.1 ​ 301.8 ​ 93.4 ​ 1,052.7 ​ Asia-Pacific ​ 140.9 ​ 72.3 ​ ​ 94.5 ​ 204.1 ​ 19.7 ​ ​ 531.5 ​ Rest of World ​ 5.2 ​ 0.2 ​ ​ 45.0 ​ — ​ — ​ 50.4 ​ Total ​ $ 567.3 ​ $ 135.2 ​ $ 649.1 ​ $ 505.9 ​ $ 119.0 ​ $ 1,976.5 ​

Investments in Unconsolidated_2

Investments in Unconsolidated Affiliates (Tables)9 Months Ended
Sep. 30, 2021
Investments in Unconsolidated Affiliates
Summarized Financial Information of Unconsolidated Affiliates​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2021 2020 2021 2020 Sales $ 433.4 $ 269.7 $ 1,351.9 $ 817.3 ​ Gross profit ​ $ 49.3 ​ $ 39.6 ​ $ 189.2 ​ $ 78.1 ​ Net income ​ $ 37.2 ​ $ 27.5 ​ $ 151.8 ​ $ 39.3 ​

Inventories (Tables)

Inventories (Tables)9 Months Ended
Sep. 30, 2021
Inventories
Schedule of Inventories​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 ​ 2020 Finished goods $ 314.0 $ 132.9 Raw materials and semi-finished goods ​ 265.5 ​ 161.7 Supplies ​ 37.8 ​ 29.5 Total ​ $ 617.3 ​ $ 324.1

Debt (Tables)

Debt (Tables)9 Months Ended
Sep. 30, 2021
Debt
Schedule of Debt [Table Text Block]​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ December 31, 2020 ​ ​ Interest Rate as of Maturity Date Carrying Amount Unamortized Deferred Financing Fees (1) Total Debt, Less Unamortized Deferred Financing Fees Carrying Amount Unamortized Deferred Financing Fees (1) Total Debt, Less ​ Senior Credit Facility ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2024 Term Loan B ​ 2.081% ​ September 2024 ​ $ 672.1 ​ $ (8.7) ​ $ 663.4 ​ $ 677.3 ​ $ (10.8) ​ $ 666.5 ​ 2028 Term Loan B ​ 2.584% ​ May 2028 ​ ​ 744.6 ​ ​ (17.6) ​ ​ 727.0 ​ ​ — ​ ​ — ​ ​ — ​ 2026 Revolving Facility (2) ​ Various ​ May 2026 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ 2029 Senior Notes ​ 5.125% ​ April 2029 ​ ​ 450.0 ​ ​ (15.1) ​ ​ 434.9 ​ ​ — ​ ​ — ​ ​ — ​ 2025 Senior Notes ​ 5.375% ​ September 2025 ​ ​ 500.0 ​ ​ (5.3) ​ ​ 494.7 ​ ​ 500.0 ​ ​ (6.2) ​ ​ 493.8 ​ Accounts Receivable Securitization Facility (3) ​ Various ​ November 2021 ​ ​ 130.0 ​ ​ — ​ ​ 130.0 ​ ​ — ​ ​ — ​ ​ — ​ Other indebtedness ​ Various ​ Various ​ ​ 7.0 ​ ​ — ​ ​ 7.0 ​ ​ 10.0 ​ ​ — ​ ​ 10.0 ​ Total debt ​ ​ ​ ​ ​ $ 2,503.7 ​ $ (46.7) ​ $ 2,457.0 ​ $ 1,187.3 ​ $ (17.0) ​ $ 1,170.3 ​ Less: current portion (4) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (149.1) ​ ​ ​ ​ ​ ​ ​ ​ (12.2) ​ Total long-term debt, net of unamortized deferred financing fees ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 2,307.9 ​ ​ ​ ​ ​ ​ ​ $ 1,158.1 ​ (1) This caption does not include deferred financing fees related to the Company’s revolving facilities, which are included within “Deferred charges and other assets” on the condensed consolidated balance sheets. (2) On May 3, 2021, in conjunction with the PMMA Acquisition, the Company extended its Revolving Facility (previously the “2022 Revolving Facility,” now the “2026 Revolving Facility”), originally maturing in September 2022, to May 2026, as described further below. As of September 30, 2021, under the 2026 Revolving Facility, the Company had a capacity of $375.0 million and funds available for borrowing of $366.9 million (net of $8.1 million outstanding letters of credit). Additionally, the Company is required to pay a quarterly commitment fee in respect of any unused commitments under this facility equal to 0.375% per annum. (3) On August 27, 2021, in conjunction with the Aristech Surfaces Acquisition, the Company drew $150.0 million on its Accounts Receivable Securitization Facility, of which $20.0 million was repaid in September 2021. Further, in September 2021, the Company extended the maturity date of the facility to November 2021. As of September 30, 2021, this facility had a borrowing capacity of $150.0 million, and the Company had approximately $20.0 million of funds available for borrowing under this facility, based on the pool of eligible accounts receivable. (4) As of September 30, 2021, the current portion of long-term debt was primarily related to a $130.0 million balance on the Accounts Receivable Securitization Facility and $14.5 million of the scheduled future principal payments on both the 2024 Term Loan B and 2028 Term Loan B. As of December 31, 2020, the current portion of long-term debt was primarily related to $7.0 million of the scheduled future principal payments on the 2024 Term Loan B.
Redemption Price as Percentage of Principal Amount to Applicable Date of Redemption​ ​ ​ ​ ​ 12-month period commencing April 1 in Year ​ Percentage ​ 2024 102.563 % 2025 101.281 % 2026 and thereafter 100.000 %

Goodwill (Tables)

Goodwill (Tables)9 Months Ended
Sep. 30, 2021
Goodwill.
Changes in Carrying Amount of Goodwill, by Segment​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Latex ​ Engineered ​ Base ​ ​ ​ ​ ​ Americas ​ ​ ​ ​ Binders ​ Materials Plastics Polystyrene Feedstocks Styrenics Total Balance at December 31, 2020 ​ $ 17.1 ​ $ 16.0 ​ $ 24.2 ​ $ 4.8 ​ $ — ​ $ — ​ $ 62.1 ​ Acquisitions (Note 3) ​ ​ — ​ ​ 670.8 ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 670.8 ​ Foreign currency impact ​ (1.0) ​ ​ (10.5) ​ ​ (1.3) ​ ​ (0.2) ​ ​ — ​ ​ — ​ (13.0) ​ Balance at September 30, 2021 ​ $ 16.1 ​ $ 676.3 ​ $ 22.9 ​ $ 4.6 ​ $ — ​ $ — ​ $ 719.9 ​

Derivative Instruments (Tables)

Derivative Instruments (Tables)9 Months Ended
Sep. 30, 2021
Derivative Instruments [Abstract]
Notional Amounts of Most Significant Net Foreign Exchange Hedge Positions Outstanding​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ Buy / (Sell) 2021 ​ Euro ​ $ (1,037.4) ​ Chinese Yuan ​ $ (38.6) ​ Swiss Franc ​ $ 32.8 ​ Mexican Peso ​ $ (17.8) ​ Korean Won ​ $ (15.3) ​
Schedule of Effect of Derivative Instruments on Statements of Operations​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Location and Amount of Gain (Loss) Recognized in ​ ​ ​ Three Months Ended ​ Three Months Ended ​ ​ ​ September 30, 2021 ​ September 30, 2020 ​ ​ Cost of ​ Interest expense, net ​ Acquisition purchase price hedge gain (loss) ​ Other income, net ​ Cost of ​ Interest expense, net ​ Acquisition purchase price hedge gain (loss) ​ Other expense, net Total amount of income and (expense) line items presented in the statements of operations in which the effects of derivative instruments are recorded ​ $ (1,101.0) ​ $ (23.0) ​ $ — ​ $ 0.1 ​ $ (572.9) ​ $ (10.0) ​ $ — ​ $ (1.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The effects of cash flow hedge instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange cash flow hedges ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain (loss) reclassified from AOCI into income ​ $ 0.3 ​ $ — ​ $ — ​ $ — ​ $ (0.7) ​ $ — ​ $ — ​ $ — ​ Interest rate swaps ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of loss reclassified from AOCI into income ​ $ — ​ $ (0.9) ​ $ — ​ $ — ​ $ — ​ $ (0.8) ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The effects of net investment hedge instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cross currency swaps (CCS) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain excluded from effectiveness testing ​ $ — ​ $ 1.9 ​ $ — ​ $ — ​ $ — ​ $ 1.6 ​ $ — ​ $ — ​ Amount of loss recognized in income (1) ​ $ — ​ $ — ​ $ — ​ $ ​ ​ $ — ​ $ — ​ $ — ​ $ (0.8) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The effects of derivatives not designated as hedge instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange forward contracts ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain (loss) recognized in income ​ $ — ​ $ — ​ $ — ​ $ 23.3 ​ $ — ​ $ — ​ $ — ​ $ (13.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Location and Amount of Gain (Loss) Recognized in ​ ​ Nine Months Ended ​ Nine Months Ended ​ ​ ​ September 30, 2021 ​ September 30, 2020 ​ ​ Cost of Interest expense, net ​ Acquisition purchase price hedge gain (loss) ​ Other expense, net Cost of Interest expense, net ​ Acquisition purchase price hedge gain (loss) ​ Other expense, net Total amount of income and (expense) line items presented in the statements of operations in which the effects of derivative instruments are recorded ​ $ (2,951.7) ​ $ (56.6) ​ $ (22.0) ​ $ (8.4) ​ $ (1,789.1) ​ $ (32.0) ​ $ — ​ $ (3.0) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effects of cash flow hedge instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange cash flow hedges ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain reclassified from AOCI into income ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ $ — ​ Interest rate swaps ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of loss reclassified from AOCI into income ​ $ — ​ $ (2.6) ​ $ — ​ $ — ​ $ — ​ $ (1.6) ​ $ — ​ $ — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effects of net investment hedge instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cross currency swaps ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain excluded from effectiveness testing (2) ​ $ — ​ $ 5.5 ​ $ — ​ $ — ​ $ — ​ $ 7.0 ​ $ — ​ $ — ​ Amount of loss recognized in income (1) ​ $ — ​ $ — ​ $ — ​ $ ​ ​ $ — ​ $ — ​ $ — ​ $ (0.8) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effects of derivatives not designated as hedge instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange forward contracts ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of gain (loss) recognized in income (3) ​ $ — ​ $ — ​ $ (22.0) ​ $ 43.4 ​ $ — ​ $ — ​ $ — ​ $ (7.5) ​ (1) Amount represents the change in fair value of the portion of the 2020 CCS that was de-designated from hedge accounting for the three and nine months ended September 30, 2020. (2) Amounts include the effects on AOCI of both the 2017 CCS through its settlement on February 26, 2020 and the 2020 CCS from when it was entered into on February 26, 2020 through September 30, 2020. (3) The $22.0 million loss incurred from the change in fair value of the forward currency hedge arrangement on the euro-denominated purchase price of the Arkema PMMA business during the nine months ended September 30, 2021 is presented separately in the condensed consolidated statements of operations from the gains recorded on the Company’s other foreign exchange forward contracts. ​
Schedule of Effect of Hedges on AOCI​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ` ​ Gain (Loss) Recognized in AOCI on Balance Sheet ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ September 30, ​ September 30, ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 Designated as Cash Flow Hedges ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange cash flow hedges $ 0.4 $ (0.3) $ 3.1 $ 0.6 Interest rate swaps ​ ​ 0.8 ​ ​ 0.7 ​ ​ 2.5 ​ ​ (5.2) Total ​ $ 1.2 ​ $ 0.4 ​ $ 5.6 ​ $ (4.6) Designated as Net Investment Hedges ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cross currency swaps (CCS) (1) ​ $ 13.1 ​ $ (24.2) ​ $ 32.1 ​ $ (11.6) Total ​ $ 13.1 ​ $ (24.2) ​ $ 32.1 ​ $ (11.6) (1) Amount for the nine months ended September 30, 2020 includes the effects on AOCI of both the 2017 CCS through its settlement on February 26, 2020 and the 2020 CCS from when it was entered into on February 26, 2020 through September 30, 2020. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gain (Loss) Recognized in Other expense, net in Statement of Operations ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2021 2020 2021 2020 ​ Settlements and changes in the fair value of forward contracts (not designated as hedges) (1) $ 23.3 $ (13.2) $ 43.4 $ (7.5) ​ Remeasurement of foreign currency-denominated assets and liabilities ​ $ (23.7) ​ $ 14.0 ​ $ (43.0) ​ $ 8.9 ​ Total ​ $ (0.4) ​ $ 0.8 ​ $ 0.4 ​ $ 1.4 ​ (1) Amounts do not include the loss of $22.0 million recorded from the change in fair value of the forward currency hedge arrangement on the euro-denominated purchase price of the Arkema PMMA business during the nine months ended September 30, 2021. ​
Schedule of Gross and Net Unrealized Gains and Losses and Balance Sheet Classification​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ ​ Foreign ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exchange ​ Exchange ​ Interest ​ Cross ​ ​ ​ ​ Balance Sheet ​ Forward ​ Cash Flow ​ Rate ​ Currency ​ ​ ​ Classification Contracts ​ Hedges ​ Swaps ​ Swaps ​ Total ​ Asset Derivatives: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts receivable, net of allowance ​ $ 18.6 ​ $ 0.9 ​ $ — ​ $ 4.2 ​ $ 23.7 ​ Gross derivative asset position ​ ​ 18.6 ​ ​ 0.9 ​ ​ — ​ ​ 4.2 ​ ​ 23.7 ​ Less: Counterparty netting ​ ​ (0.1) ​ ​ — ​ ​ — ​ ​ — ​ ​ (0.1) ​ Net derivative asset position ​ $ 18.5 ​ $ 0.9 ​ $ — ​ $ 4.2 ​ $ 23.6 ​ Liability Derivatives: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts payable ​ $ (0.8) ​ $ — ​ $ (3.4) ​ $ — ​ $ (4.2) ​ Other noncurrent obligations ​ ​ — ​ ​ — ​ ​ — ​ ​ (33.7) ​ ​ (33.7) ​ Gross derivative liability position ​ ​ (0.8) ​ ​ — ​ ​ (3.4) ​ ​ (33.7) ​ ​ (37.9) ​ Less: Counterparty netting ​ ​ 0.1 ​ ​ — ​ ​ — ​ ​ — ​ ​ 0.1 ​ Net derivative liability position ​ $ (0.7) ​ $ — ​ $ (3.4) ​ $ (33.7) ​ $ (37.8) ​ Total net derivative position ​ $ 17.8 ​ $ 0.9 ​ $ (3.4) ​ $ (29.5) ​ $ (14.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Foreign ​ Foreign ​ ​ ​ ​ ​ ​ ​ ​ Exchange ​ Exchange ​ Interest ​ Cross ​ ​ ​ ​ Balance Sheet ​ Forward ​ Cash Flow ​ Rate ​ Currency ​ ​ Classification Contracts Hedges Swaps Swaps Total Asset Derivatives: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts receivable, net of allowance (1) ​ $ 8.2 ​ $ — ​ $ — ​ $ 5.0 ​ $ 13.2 ​ Gross derivative asset position ​ ​ 8.2 ​ ​ — ​ ​ — ​ ​ 5.0 ​ ​ 13.2 ​ Less: Counterparty netting ​ ​ (6.5) ​ ​ — ​ ​ — ​ ​ — ​ ​ (6.5) ​ Net derivative asset position ​ $ 1.7 ​ $ — ​ $ — ​ $ 5.0 ​ $ 6.7 ​ Liability Derivatives: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts payable (1) ​ $ (8.3) ​ $ (2.1) ​ $ (3.4) ​ $ — ​ $ (13.8) ​ Other noncurrent obligations ​ ​ — ​ ​ — ​ ​ (2.5) ​ ​ (66.5) ​ ​ (69.0) ​ Gross derivative liability position ​ ​ (8.3) ​ ​ (2.1) ​ ​ (5.9) ​ ​ (66.5) ​ ​ (82.8) ​ Less: Counterparty netting ​ ​ 6.5 ​ ​ — ​ ​ — ​ ​ — ​ ​ 6.5 ​ Net derivative liability position ​ $ (1.8) ​ $ (2.1) ​ $ (5.9) ​ $ (66.5) ​ $ (76.3) ​ Total net derivative position ​ $ (0.1) ​ $ (2.1) ​ $ (5.9) ​ $ (61.5) ​ $ (69.6) ​ (1) Balance as of December 31, 2020 includes a $7.3 million receivable representing the fair value of the forward currency hedge arrangement on the euro-denominated purchase price of the Arkema PMMA business.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)9 Months Ended
Sep. 30, 2021
Fair Value Measurements
Schedule of Assets and Liabilities at Fair Value on Recurring Basis​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ ​ Quoted Prices in Active Markets for Identical Items ​ Significant Other Observable Inputs ​ Significant Unobservable Inputs ​ ​ ​ Assets (Liabilities) at Fair Value (Level 1) (Level 2) (Level 3) Total Foreign exchange forward contracts—Assets $ — $ 18.5 $ — $ 18.5 ​ Foreign exchange forward contracts—(Liabilities) ​ — ​ (0.7) ​ — ​ (0.7) ​ Foreign exchange cash flow hedges—Assets ​ ​ — ​ ​ 0.9 ​ ​ — ​ ​ 0.9 ​ Interest rate swaps—(Liabilities) ​ ​ — ​ ​ (3.4) ​ ​ — ​ ​ (3.4) ​ Cross currency swaps—Assets ​ ​ — ​ ​ 4.2 ​ ​ — ​ ​ 4.2 ​ Cross currency swaps—(Liabilities) ​ ​ — ​ ​ (33.7) ​ ​ — ​ ​ (33.7) ​ Total fair value ​ $ — ​ $ (14.2) ​ $ — ​ $ (14.2) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ Quoted Prices in Active Markets for Identical Items ​ Significant Other Observable Inputs ​ Significant Unobservable Inputs ​ ​ ​ Assets (Liabilities) at Fair Value (Level 1) (Level 2) (Level 3) Total Foreign exchange forward contracts—Assets ​ $ — $ 1.7 $ — $ 1.7 ​ Foreign exchange forward contracts—(Liabilities) ​ ​ — ​ ​ (1.8) ​ ​ — ​ ​ (1.8) ​ Foreign exchange cash flow hedges—(Liabilities) ​ ​ — ​ ​ (2.1) ​ ​ — ​ ​ (2.1) ​ Interest rate swaps—(Liabilities) ​ ​ — ​ ​ (5.9) ​ ​ — ​ ​ (5.9) ​ Cross currency swaps—Assets ​ ​ — ​ ​ 5.0 ​ ​ — ​ ​ 5.0 ​ Cross currency swaps—(Liabilities) ​ ​ — ​ ​ (66.5) ​ ​ — ​ ​ (66.5) ​ Total fair value ​ $ — ​ $ (69.6) ​ $ — ​ $ (69.6) ​
Estimated Fair Value of Outstanding Debt Not Carried at Fair Value​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ As of ​ September 30, 2021 December 31, 2020 2029 Senior Notes ​ $ 455.5 ​ $ — ​ 2028 Term Loan B ​ ​ 742.7 ​ ​ — ​ 2025 Senior Notes ​ ​ 509.7 ​ ​ 513.5 ​ 2024 Term Loan B ​ ​ 670.4 ​ ​ 674.0 ​ Total fair value ​ $ 2,378.3 ​ $ 1,187.5 ​

Provision for Income Taxes (Tab

Provision for Income Taxes (Tables)9 Months Ended
Sep. 30, 2021
Provision for Income Taxes
Schedule of Effective Tax Rate​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2021 2020 2021 2020 ​ Effective income tax rate ​ ​ 6.5 % ​ 40.1 % ​ 14.9 % ​ 126.5 % ​

Pension Plans and Other Postr_2

Pension Plans and Other Postretirement Benefits (Tables)9 Months Ended
Sep. 30, 2021
Pension Plans and Other Postretirement Benefits
Schedule of Net Periodic Benefit Costs​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2021 2020 2021 2020 Defined Benefit Pension Plans (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service cost ​ $ 4.2 ​ $ 3.3 $ 12.4 ​ $ 9.8 ​ Interest cost ​ 0.4 ​ 0.8 ​ 1.4 ​ 2.2 ​ Expected return on plan assets ​ (0.3) ​ (0.3) ​ (0.6) ​ (0.9) ​ Amortization of prior service credit ​ (0.5) ​ (0.3) ​ (0.9) ​ (0.9) ​ Amortization of net loss ​ 1.6 ​ 1.0 ​ 4.7 ​ 3.1 ​ Settlement and curtailment (gain) loss ​ (2.3) ​ 1.1 ​ (2.3) ​ 1.1 ​ Net periodic benefit cost ​ $ 3.1 ​ $ 5.6 ​ $ 14.7 ​ $ 14.4 ​ (1) All amounts represent components of net periodic benefit costs.

Share-Based Compensation (Table

Share-Based Compensation (Tables)9 Months Ended
Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Share-Based Compensation Expense and Unrecognized Compensation Cost​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ September 30, 2021 ​ ​ ​ September 30, ​ September 30, ​ Unrecognized ​ Weighted ​ ​ 2021 2020 2021 2020 Compensation Cost Average Years ​ RSUs ​ $ 2.1 ​ $ 1.5 ​ $ 5.7 ​ $ 4.9 ​ $ 13.60 ​ 2.0 ​ Options ​ ​ 1.2 ​ ​ 0.6 ​ ​ 3.5 ​ ​ 2.3 ​ ​ 4.60 ​ 1.5 ​ PSUs ​ ​ 0.7 ​ ​ 0.5 ​ ​ 1.8 ​ ​ 1.5 ​ ​ 3.70 ​ 1.9 ​ Total share-based compensation expense ​ $ 4.0 ​ $ 2.6 ​ $ 11.0 ​ $ 8.7 ​ ​ ​ ​ ​ ​
Summary of Awards Granted and Weighted Average Grant-Date Fair Value​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ ​ ​ September 30, 2021 ​ ​ ​ Awards Granted ​ Weighted Average Grant Date Fair Value per Award ​ RSUs ​ ​ 212,167 ​ $ 58.59 ​ Options ​ ​ 296,354 ​ ​ 22.61 ​ PSUs ​ ​ 49,463 ​ ​ 61.06 ​
Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Weighted-average Assumptions​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ ​ September 30, 2021 ​ Expected term (in years) 5.50 ​ Expected volatility 48.69 % Risk-free interest rate 0.78 % Dividend yield ​ 1.81 %
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Weighted-average Assumptions​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ ​ ​ September 30, 2021 ​ Expected term (in years) ​ 3.00 ​ Expected volatility 58.00 % Risk-free interest rate 0.20 % Share price $ 61.06 ​

Segments (Tables)

Segments (Tables)9 Months Ended
Sep. 30, 2021
Segments
Schedule of Segment Reporting Information, by Segment [Table Text Block]​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Latex ​ Engineered ​ Base ​ ​ ​ ​ ​ Americas Three Months Ended (1) ​ Binders ​ Materials ​ Plastics ​ Polystyrene ​ Feedstocks ​ Styrenics September 30, 2021 $ 37.1 $ 32.7 ​ $ 87.9 ​ $ 51.2 $ (27.6) $ 17.1 ​ September 30, 2020 ​ $ 18.7 ​ $ 9.4 ​ $ 40.5 ​ $ 20.4 ​ $ 10.1 ​ $ 18.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Latex ​ Engineered ​ Base ​ ​ ​ ​ ​ Americas Nine Months Ended (1) ​ Binders ​ Materials ​ Plastics ​ Polystyrene ​ Feedstocks ​ Styrenics September 30, 2021 ​ $ 86.2 ​ $ 68.5 ​ $ 235.0 ​ $ 149.6 ​ $ 58.5 ​ $ 70.2 ​ September 30, 2020 ​ $ 55.4 ​ $ 22.3 ​ $ 55.6 ​ $ 46.4 ​ $ (10.6) ​ $ 42.5 ​ (1) The Company’s primary measure of segment operating performance is Adjusted EBITDA, which is defined as income from continuing operations before interest expense, net; provision for income taxes; depreciation and amortization expense; loss on extinguishment of long-term debt; asset impairment charges; gains or losses on the dispositions of businesses and assets; restructuring charges; acquisition related costs and benefits and other items. Segment Adjusted EBITDA is a key metric that is used by management to evaluate business performance in comparison to budgets, forecasts, and prior year financial results, providing a measure that management believes reflects core operating performance by removing the impact of transactions and events that would not be considered a part of core operations. Other companies in the industry may define segment Adjusted EBITDA differently than the Company, and as a result, it may be difficult to use segment Adjusted EBITDA, or similarly named financial measures, that other companies may use to compare the performance of those companies to the Company’s segment performance.
Reconciliation of IBT to Adjusted EBITDA​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ 2021 2020 2021 2020 Income from continuing operations before income taxes ​ $ 84.9 ​ $ 67.1 ​ $ 327.1 ​ $ 12.8 ​ Interest expense, net ​ 23.0 ​ 10.0 ​ 56.6 ​ 32.0 ​ Depreciation and amortization ​ 49.8 ​ 21.2 ​ ​ 111.0 ​ 69.8 ​ Corporate Unallocated (2) ​ ​ 25.0 ​ ​ 16.6 ​ ​ 71.3 ​ ​ 56.1 ​ Adjusted EBITDA Addbacks (3) ​ 15.7 ​ 2.5 ​ 102.0 ​ 40.9 ​ Segment Adjusted EBITDA ​ $ 198.4 ​ $ 117.4 ​ $ 668.0 ​ $ 211.6 ​ (2) Corporate unallocated includes corporate overhead costs and certain other income and expenses. (3) Adjusted EBITDA addbacks for the three and nine months ended September 30, 2021 and 2020 are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ ​ ​ 2021 2020 2021 2020 Net gain on disposition of businesses and assets ​ $ — ​ $ — ​ $ (0.2) ​ $ (0.4) ​ Restructuring and other charges (Note 17) ​ ​ 0.2 ​ ​ (0.1) ​ ​ 6.8 ​ ​ 7.0 ​ Acquisition transaction and integration net costs (a) ​ ​ 13.6 ​ ​ — ​ ​ 62.8 ​ ​ (0.3) ​ Acquisition purchase price hedge loss (Note 10) ​ ​ — ​ ​ — ​ ​ 22.0 ​ ​ — ​ Asset impairment charges or write-offs (Note 11) ​ ​ 1.2 ​ ​ — ​ ​ 3.0 ​ ​ 10.3 ​ Other items (b) ​ ​ 0.7 ​ ​ 2.6 ​ ​ 7.6 ​ ​ 24.3 ​ Total Adjusted EBITDA Addbacks ​ $ 15.7 ​ $ 2.5 ​ $ 102.0 ​ $ 40.9 ​ (a) Amounts for the three months ended September 30, 2021 include $10.1 million of total acquisition and integration costs and $3.5 million related to amortization of the fair-value step-up to inventory associated with the Aristech Surfaces Acquisition. Amounts for the nine months ended September 30, 2021 include $44.7 million of total acquisition and integration costs, $13.6 million related to amortization of the fair-value step-up to inventory associated with acquisitions, and $4.5 million of transfer taxes associated with the PMMA Acquisition. Refer to Note 3 for further information (b) Other items for the three and nine months ended September 30, 2021 primarily relate to fees incurred in conjunction with certain of the Company’s strategic initiatives, including the ERP upgrade project. Other items for the three and nine months ended September 30, 2020 primarily relate to advisory and professional fees incurred in conjunction with the Company’s initiative to transition business services from Dow, including certain administrative services such as accounts payable, logistics, and IT services, which was substantially completed in 2020, as well as fees incurred in conjunction with certain of the Company’s strategic initiatives.

Restructuring (Tables)

Restructuring (Tables)9 Months Ended
Sep. 30, 2021
Restructuring
Detail of Restructuring Charges​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ Cumulative ​ ​ ​ ​ ​ September 30, ​ September 30, ​ Life-to-date ​ ​ ​ ​ ​ 2021 2020 ​ 2021 2020 ​ Charges Segment ​ Corporate Restructuring Program ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accelerated depreciation ​ $ — ​ $ — ​ $ (0.4) ​ $ 2.5 ​ $ 2.5 ​ ​ ​ Employee termination benefits ​ ​ (0.1) ​ ​ (0.5) ​ ​ 0.4 ​ ​ 3.9 ​ ​ 19.9 ​ ​ ​ Contract terminations ​ ​ — ​ ​ — ​ ​ — ​ ​ 2.4 ​ ​ 2.8 ​ ​ ​ Decommissioning and other ​ ​ — ​ ​ 0.2 ​ ​ — ​ ​ 0.2 ​ ​ 0.2 ​ ​ ​ Corporate Program Subtotal ​ $ (0.1) ​ $ (0.3) ​ $ — ​ $ 9.0 ​ $ 25.4 ​ N/A (1) ​ Transformational Restructuring Program ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Employee termination benefits ​ $ 0.3 ​ $ — ​ $ 6.4 ​ $ — ​ $ 6.4 ​ N/A (2) ​ Transformational Program Subtotal ​ $ 0.3 ​ $ — ​ $ 6.4 ​ $ — ​ $ 6.4 ​ ​ ​ Other Restructurings ​ ​ — ​ ​ 0.2 ​ ​ — ​ ​ 0.5 ​ ​ ​ ​ Various ​ Total Restructuring Charges ​ $ 0.2 ​ $ (0.1) ​ $ 6.4 ​ $ 9.5 ​ ​ ​ ​ ​ ​ (1) In November 2019, the Company announced a corporate restructuring program associated with the Company’s shift to a global functional structure and business excellence initiatives to drive greater focus on business process optimization and efficiency, which continued through the three and nine months ended September 30, 2021. The Company expects to incur a limited amount of incremental employee termination benefit charges through the end of 2021, and the majority of these benefits are expected to be paid by the end of 2021. As this was identified as a corporate-related activity, the charges related to this restructuring program were not allocated to a specific segment, but rather included within corporate unallocated. (2) In May 2021, the Company approved a transformational restructuring program associated with the Company’s recent strategic initiatives. In connection with this restructuring program, during the three and nine months ended September 30, 2021, the Company incurred employee termination benefits charges of $0.3 million and $6.4 million, respectively. The Company expects to incur incremental employee termination benefit charges related to impacted employees as of September 30, 2021 of less than $1.0 million, the majority of which are expected to be paid by June 30, 2022. As this was identified as a corporate-related activity, the charges related to this restructuring program were not allocated to a specific segment, but rather included within corporate unallocated.
Rollforward of Liability Balances​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ ​ ​ Balance at ​ December 31, 2020 Expenses Deductions (1) September 30, 2021 Employee termination benefits ​ $ 7.9 ​ $ 6.8 ​ $ (5.4) ​ $ 9.3 ​ Contract terminations ​ ​ 0.1 ​ ​ — ​ ​ (0.1) ​ ​ — ​ Total ​ $ 8.0 ​ $ 6.8 ​ $ (5.5) ​ $ 9.3 ​ (1) Primarily includes payments made against the existing accrual, as well as immaterial impacts of foreign currency remeasurement.

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)9 Months Ended
Sep. 30, 2021
Shareholders' Equity.
Components of AOCI, Net of Income Taxes​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cumulative Pension & Other ​ ​ ​ ​ ​ ​ ​ ​ Translation ​ Postretirement Benefit ​ ​ Cash Flow ​ ​ ​ ​ Three Months Ended September 30, 2021 and 2020 Adjustments Plans, Net ​ Hedges, Net Total Balance as of June 30, 2021 ​ $ (109.3) ​ $ (69.8) ​ $ (0.8) ​ $ (179.9) ​ Other comprehensive income (loss) ​ (1.7) ​ 9.3 ​ 0.6 ​ 8.2 ​ Amounts reclassified from AOCI to net income (1) ​ ​ — ​ ​ (1.2) ​ ​ 0.6 ​ ​ (0.6) ​ Balance as of September 30, 2021 ​ $ (111.0) ​ $ (61.7) ​ $ 0.4 ​ $ (172.3) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance as of June 30, 2020 ​ $ (97.1) ​ $ (54.6) ​ $ (4.4) ​ $ (156.1) ​ Other comprehensive income (loss) ​ (6.7) ​ 0.1 ​ (1.1) ​ (7.7) ​ Amounts reclassified from AOCI to net income (1) ​ ​ — ​ ​ 1.6 ​ ​ 1.5 ​ ​ 3.1 ​ Balance as of September 30, 2020 ​ $ (103.8) ​ $ (52.9) ​ $ (4.0) ​ $ (160.7) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cumulative Pension & Other ​ ​ ​ ​ ​ ​ ​ Translation ​ Postretirement Benefit ​ Cash Flow ​ ​ ​ ​ Nine Months Ended September 30, 2021 and 2020 ​ Adjustments Plans, Net Hedges, Net Total ​ Balance as of December 31, 2020 ​ $ (109.0) ​ $ (71.9) ​ $ (5.2) ​ $ (186.1) ​ Other comprehensive income (loss) ​ (2.0) ​ 9.3 ​ 3.0 ​ 10.3 ​ Amounts reclassified from AOCI to net income (1) ​ ​ — ​ ​ 0.9 ​ ​ 2.6 ​ ​ 3.5 ​ Balance as of September 30, 2021 ​ $ (111.0) ​ $ (61.7) ​ $ 0.4 ​ $ (172.3) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance as of December 31, 2019 ​ $ (106.7) ​ $ (56.3) ​ $ 0.6 ​ $ (162.4) ​ Other comprehensive income (loss) ​ 2.9 ​ 0.7 ​ (6.2) ​ (2.6) ​ Amounts reclassified from AOCI to net loss (1) ​ ​ — ​ ​ 2.7 ​ ​ 1.6 ​ ​ 4.3 ​ Balance as of September 30, 2020 ​ $ (103.8) ​ $ (52.9) ​ $ (4.0) ​ $ (160.7) ​
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ ​ ​ September 30, ​ September 30, ​ Statements of Operations ​ AOCI Components 2021 2020 2021 2020 Classification ​ Cash flow hedging items ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Foreign exchange cash flow hedges ​ $ (0.3) ​ $ 0.7 ​ $ — ​ $ — ​ Cost of sales ​ Interest rate swaps ​ ​ 0.9 ​ ​ 0.8 ​ ​ 2.6 ​ ​ 1.6 ​ Interest expense, net ​ Total before tax ​ ​ 0.6 ​ ​ 1.5 ​ ​ 2.6 ​ ​ 1.6 ​ ​ ​ Tax effect ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ Provision for income taxes ​ Total, net of tax ​ $ 0.6 ​ $ 1.5 ​ $ 2.6 ​ $ 1.6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization of pension and other postretirement benefit plan items ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Prior service credit ​ $ (0.2) ​ $ (0.3) ​ $ (0.7) ​ $ (0.9) ​ (a) ​ Net actuarial loss ​ ​ 1.7 ​ ​ 1.2 ​ ​ 5.3 ​ ​ 3.5 ​ (a) ​ Net curtailment and settlement (gain) loss ​ ​ (2.5) ​ ​ 1.1 ​ ​ (2.5) ​ ​ 1.1 ​ (a) ​ Total before tax ​ ​ (1.0) ​ ​ 2.0 ​ ​ 2.1 ​ ​ 3.7 ​ ​ ​ Tax effect ​ ​ (0.2) ​ ​ (0.4) ​ ​ (1.2) ​ ​ (1.0) ​ Provision for income taxes ​ Total, net of tax ​ $ (1.2) ​ $ 1.6 ​ $ 0.9 ​ $ 2.7 ​ ​ ​ (a) These AOCI components are included in the computation of net periodic benefit costs (see Note 14).

Earnings Per Share (Tables)

Earnings Per Share (Tables)9 Months Ended
Sep. 30, 2021
Earnings Per Share
Schedule of Earnings per Share Basic and Diluted​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Nine Months Ended ​ ​ ​ September 30, ​ September 30, ​ (in millions, except per share data) 2021 2020 2021 2020 Earnings: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) from continuing operations ​ $ 79.4 ​ $ 40.2 ​ $ 278.2 ​ $ (3.4) ​ Net income (loss) from discontinued operations ​ ​ 13.7 ​ ​ 65.6 ​ ​ 38.0 ​ ​ (55.4) ​ Net income (loss) ​ $ 93.1 ​ $ 105.8 ​ $ 316.2 ​ $ (58.8) ​ Shares: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average ordinary shares outstanding ​ 38.8 ​ 38.3 ​ 38.7 ​ 38.4 ​ Dilutive effect of RSUs, option awards, and PSUs (1) ​ 0.7 ​ 0.1 ​ 0.9 ​ — ​ Diluted weighted average ordinary shares outstanding ​ 39.5 ​ 38.4 ​ 39.6 ​ 38.4 ​ Income (loss) per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income (loss) per share—basic: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Continuing operations ​ ​ 2.04 ​ ​ 1.05 ​ ​ 7.19 ​ ​ (0.09) ​ Discontinued operations ​ ​ 0.35 ​ ​ 1.72 ​ ​ 0.98 ​ ​ (1.44) ​ Income (loss) per share—basic ​ $ 2.39 ​ $ 2.77 ​ $ 8.17 ​ $ (1.53) ​ Income (loss) per share—diluted: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Continuing operations ​ ​ 2.01 ​ ​ 1.04 ​ ​ 7.03 ​ ​ (0.09) ​ Discontinued operations ​ ​ 0.35 ​ ​ 1.71 ​ ​ 0.96 ​ ​ (1.44) ​ Income (loss) per share—diluted ​ $ 2.36 ​ $ 2.75 ​ $ 7.99 ​ $ (1.53) ​ (1) Refer to Note 15 for discussion of RSUs, option awards, and PSUs granted to certain Company directors and employees. There were 0.6 million anti-dilutive shares that have been excluded from the computation of diluted earnings per share for the three and nine months ended September 30, 2021. There were 1.6 million anti-dilutive shares that have been excluded from the computation of diluted earnings per share for the three months ended September 30, 2020. As the Company recorded a net loss from continuing operations for the nine months ended September 30, 2020, potential shares related to equity-based awards have been excluded from the calculation of diluted EPS, as doing so would be anti-dilutive.

Basis of Presentation (Details)

Basis of Presentation (Details) - $ / sharesOct. 08, 2021Sep. 30, 2021Dec. 31, 2020
Organization and Business Activities
Ordinary shares, nominal value $ 0.01 $ 0.01
Subsequent Event [Member]
Organization and Business Activities
Ordinary shares, nominal value $ 0.01

Acquisitions - Aristech (Detail

Acquisitions - Aristech (Details) - USD ($) $ in MillionsSep. 01, 2021Sep. 30, 2021Sep. 30, 2021Dec. 31, 2020
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill $ 719.9 $ 719.9 $ 62.1
Acquisition-related costs10.1 44.7
Inventory adjustment13.6
Aristech Surfaces L L C [Member]
Business Acquisition [Line Items]
Equity interest acquired100.00%
Total Consideration $ 449.7
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Cash and cash equivalents1.7
Accounts receivable26.9
Inventories30.3
Other current assets1.9
Property, plant, and equipment75.3
Right of use assets - operating2
Other intangible assets0.3
Deferred charges and other assets0.8
Total fair value of assets acquired346.7
Accounts payable(13.8)
Current lease liabilities - operating(0.4)
Accrued expenses and other current liabilities(3.1)
Noncurrent lease liabilities - operating(1.6)
Other noncurrent obligations(1.4)
Total fair value of liabilities assumed(20.3)
Net assets acquired326.4
Goodwill123.3
Acquisition-related costs3.1 3.4
Inventory adjustment3.5
Inventory adjustment6.9 3.5
Net sales since acquisition14.8 14.8
Net income since acquisition $ (3.1) $ (3.1)
Aristech Surfaces L L C [Member] | Customer Relationships [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Other intangible assets $ 145
Expected life13 years
Aristech Surfaces L L C [Member] | Developed Technology [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Other intangible assets $ 52.5
Expected life11 years
Aristech Surfaces L L C [Member] | Trade Names [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Other intangible assets $ 10
Expected life10 years
Aristech Surfaces L L C [Member] | Other intangible assets | Minimum [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Expected life1 year
Aristech Surfaces L L C [Member] | Other intangible assets | Maximum [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Expected life5 years

Acquisition - Arkema PMMA (Deta

Acquisition - Arkema PMMA (Details) - USD ($) $ in MillionsMay 03, 2021Sep. 30, 2021Sep. 30, 2021Sep. 30, 2020Mar. 24, 2021Dec. 31, 2020
Business Acquisition [Line Items]
Proceeds from issuance of Senior Notes $ 450
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill $ 719.9 719.9 $ 62.1
Cash Acquired from Acquisition12.1 $ 0
Acquisition-related costs10.1 44.7
Inventory adjustment13.6
2029 Senior Notes
Business Acquisition [Line Items]
Debt instrument issued $ 450
2028 Term Loan B
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Maximum borrowing capacity $ 750
Arkema
Business Acquisition [Line Items]
Equity interest acquired100.00%
Cash consideration $ 1,369
Known purchase price adjustment, not yet paid(4.1)
Total Consideration1,364.9
Increase to property, plant and equipment19.4
Increase to deferred income tax liabilities5
Decrease to consideration5.8
Decrease to goodwill20.1
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Cash and cash equivalents10.4
Accounts receivable19.1
Inventories78.9
Other current assets8.7
Property, plant, and equipment255.4
Right of use assets - operating4.1
Deferred charges and other assets27.9
Total fair value of assets acquired910.5
Accounts payable(15)
Current lease liabilities - operating(1.7)
Income taxes payable(0.3)
Accrued expenses and other current liabilities(11.3)
Noncurrent lease liabilities - operating(2.5)
Deferred income tax liabilities(39.3)
Other noncurrent obligations(23.1)
Total fair value of liabilities assumed(93.2)
Net assets acquired817.3
Goodwill547.6
Acquisition-related costs $ 0.2 $ 20
Inventory adjustment10.1
Pension and other post-retirement plan liabilities $ 18.2
Goodwill, Name of Segment [Extensible List]Engineered Materials [Member]
Expected deduction for goodwill $ 310
Arkema | Scenario, Plan [Member]
Business Acquisition [Line Items]
Cash consideration1,370.7
Arkema | Customer Relationships [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Other intangible assets $ 326.6
Expected life13 years
Arkema | Developed Technology [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Other intangible assets $ 133
Expected life10 years
Arkema | Trade Names [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Other intangible assets $ 46
Expected life16 years
Arkema | Other intangible assets
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Other intangible assets $ 0.4
Arkema | Other intangible assets | Minimum [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Expected life1 year
Arkema | Other intangible assets | Maximum [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Expected life5 years
Arkema | 2029 Senior Notes
Business Acquisition [Line Items]
Proceeds from issuance of Senior Notes $ 450
Arkema | 2028 Term Loan B
Business Acquisition [Line Items]
Debt instrument issued $ 750

Acquisitions - Pro Forma and tr

Acquisitions - Pro Forma and transaction costs (Details) - USD ($) $ in MillionsMay 03, 2021Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Business Acquisition, Pro Forma Information [Abstract]
Net sales $ 1,300.2 $ 862 $ 3,863.8 $ 2,499.7
Net income94.1 104 355.1 (96.7)
Income (loss) from continuing operations80.4 38.4 317.1 (41.3)
Acquisition-related costs10.1 44.7
Net sales1,269.3 679.2 3,529 1,976.5
Net income from continuing operations79.4 $ 40.2 278.2 $ (3.4)
Arkema
Business Acquisition, Pro Forma Information [Abstract]
Net sales since acquisition332.1 332.1
Net income since acquisition(5.4)(5.4)
Acquisition-related costs0.2 $ 20
Agreement term18 months
IT separation costs capitalized $ 10.6
Net sales224.6
Net income from continuing operations $ (1.6)

Divestitures and Discontinued_3

Divestitures and Discontinued Operations (Details) - USD ($) $ in MillionsOct. 21, 2021Sep. 30, 2021May 21, 2021Dec. 31, 2020
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Total current assets $ 379.5 $ 120.3
Total current liabilities81.3 42.2
Total noncurrent liabilities42.3
Emulsion Polymers, Synthetic Rubber [Member] | Discontinued Operations, Held-for-sale [Member]
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Accounts receivable, net of allowance83.5 59.7
Inventories89.2 60.6
Total current assets172.7 120.3
Property, plant and equipment, net152.3 170.3
Goodwill11.4 12.1
Other intangibles assets, net17.5 20.2
Deferred charges and other assets25.6 25.6
Total other assets54.5 57.9
Total assets held for sale379.5 348.5
Accounts payable27.6 29.5
Accrued expenses and other current liabilities11.3 12.7
Total current liabilities38.9 42.2
Other non-current obligations42.4 42.3
Total noncurrent liabilities42.4 42.3
Total liabilities held for sale $ 81.3 $ 84.5
Emulsion Polymers, Synthetic Rubber [Member] | Discontinued Operations, Held-for-sale [Member] | Scenario, Plan [Member]
Disclosures by disposal group
Pension and other postretirement benefits $ 41.6
Emulsion Polymers, Synthetic Rubber [Member] | Discontinued Operations, Held-for-sale [Member] | Scenario, Plan [Member] | Subsequent Event [Member]
Disclosures by disposal group
Consideration $ 402.4
Reduction to consideration due to amendment of agreement. $ 47
Emulsion Polymers, Synthetic Rubber [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Scenario, Plan [Member]
Disclosures by disposal group
Consideration449.4
Working capital target $ 47

Divestitures and Discontinued_4

Divestitures and Discontinued Operations - Results (Details) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Discontinued Operation, Income (Loss) from Discontinued Operation Disclosures [Abstract]
Net income (loss) from discontinued operations $ 13.7 $ 65.6 $ 38 $ (55.4)
Emulsion Polymers, Synthetic Rubber [Member] | Discontinued Operations, Held-for-sale [Member]
Discontinued Operation, Income (Loss) from Discontinued Operation Disclosures [Abstract]
Net sales122.3 79.5 382.2 217.5
Cost of sales101.9 82.5 321.2 238.9
Gross profit (loss)20.4 (3)61 (21.4)
Selling, general and administrative expenses4.9 7.4 16.7 17.8
Impairment charges28
Operating income (loss)15.5 (10.4)44.3 (67.2)
Other income (expense), net(0.2)(0.4)(1.2)(1.1)
Income (loss) from discontinued operations before income taxes15.3 (10.8)43.1 (68.3)
Provision for income taxes1.6 (76.4)5.1 (12.9)
Net income (loss) from discontinued operations $ 13.7 $ 65.6 $ 38 $ (55.4)

Net Sales (Details)

Net Sales (Details) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Net sales $ 1,269.3 $ 679.2 $ 3,529 $ 1,976.5
Emulsion Polymers, Latex [Member]
Disaggregation of Revenue [Line Items]
Net sales315.6 183.2 877.6 567.3
Engineered Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales230.8 50 477.5 135.2
Base Plastics [Member]
Disaggregation of Revenue [Line Items]
Net sales393.3 240.1 1,119.3 649.1
Polystyrene [Member]
Disaggregation of Revenue [Line Items]
Net sales274.8 167.3 855 505.9
Feedstocks [Member]
Disaggregation of Revenue [Line Items]
Net sales54.8 38.6 199.6 119
United States [Member]
Disaggregation of Revenue [Line Items]
Net sales275 116.9 629.5 341.9
United States [Member] | Emulsion Polymers, Latex [Member]
Disaggregation of Revenue [Line Items]
Net sales86.3 54.1 228.2 167.2
United States [Member] | Engineered Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales102.4 8 174.1 25.3
United States [Member] | Base Plastics [Member]
Disaggregation of Revenue [Line Items]
Net sales82.3 52.8 216.5 143.5
United States [Member] | Feedstocks [Member]
Disaggregation of Revenue [Line Items]
Net sales4 2 10.7 5.9
Europe [Member]
Disaggregation of Revenue [Line Items]
Net sales703.8 348.9 2,022 1,052.7
Europe [Member] | Emulsion Polymers, Latex [Member]
Disaggregation of Revenue [Line Items]
Net sales153.5 79.7 431.4 254
Europe [Member] | Engineered Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales89.6 13.8 190.8 37.4
Europe [Member] | Base Plastics [Member]
Disaggregation of Revenue [Line Items]
Net sales247.3 126.8 699.2 366.1
Europe [Member] | Polystyrene [Member]
Disaggregation of Revenue [Line Items]
Net sales162.6 96.9 511.7 301.8
Europe [Member] | Feedstocks [Member]
Disaggregation of Revenue [Line Items]
Net sales50.8 31.7 188.9 93.4
Asia-Pacific [Member]
Disaggregation of Revenue [Line Items]
Net sales265 192.4 807 531.5
Asia-Pacific [Member] | Emulsion Polymers, Latex [Member]
Disaggregation of Revenue [Line Items]
Net sales73 48.1 211.1 140.9
Asia-Pacific [Member] | Engineered Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales35.9 28.1 108.1 72.3
Asia-Pacific [Member] | Base Plastics [Member]
Disaggregation of Revenue [Line Items]
Net sales43.9 40.9 144.5 94.5
Asia-Pacific [Member] | Polystyrene [Member]
Disaggregation of Revenue [Line Items]
Net sales112.2 70.4 343.3 204.1
Asia-Pacific [Member] | Feedstocks [Member]
Disaggregation of Revenue [Line Items]
Net sales4.9 19.7
Rest of World [Member]
Disaggregation of Revenue [Line Items]
Net sales25.5 21 70.5 50.4
Rest of World [Member] | Emulsion Polymers, Latex [Member]
Disaggregation of Revenue [Line Items]
Net sales2.8 1.3 6.9 5.2
Rest of World [Member] | Engineered Materials [Member]
Disaggregation of Revenue [Line Items]
Net sales2.9 0.1 4.5 0.2
Rest of World [Member] | Base Plastics [Member]
Disaggregation of Revenue [Line Items]
Net sales $ 19.8 $ 19.6 $ 59.1 $ 45

Investments in Unconsolidated_3

Investments in Unconsolidated Affiliates (Details) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021USD ($)itemSep. 30, 2020USD ($)Sep. 30, 2021USD ($)itemSep. 30, 2020USD ($)Dec. 31, 2020USD ($)
Schedule of Equity Method Investments [Line Items]
Number of joint ventures | item1 1
Equity in earnings of unconsolidated affiliates $ 17.1 $ 18.3 $ 70.2 $ 42.5
Assets
Current assets2,007 2,007 $ 1,517.1
Total assets4,764.1 4,764.1 2,845.2
Liabilities
Current liabilities1,005.1 1,005.1 533.3
Total noncurrent liabilities2,837 2,837 $ 1,721.6
Summarized Financial Information, Net Income
Gross profit168.3 106.3 577.3 187.4
Net income (loss)316.2 (58.8)
AmSty [Member]
Summarized Financial Information, Net Income
Net sales433.4 269.7 1,351.9 817.3
Gross profit49.3 39.6 189.2 78.1
Net income (loss) $ 37.2 $ 27.5 $ 151.8 $ 39.3

Investments in Unconsolidated_4

Investments in Unconsolidated Affiliates - Americas Styrenics (Details) - USD ($)3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020Dec. 31, 2020
Investments in Unconsolidated Affiliates
Investments in unconsolidated affiliates $ 250,300,000 $ 250,300,000 $ 240,100,000
AmSty [Member]
Investments in Unconsolidated Affiliates
Investments in unconsolidated affiliates250,300,000 250,300,000 240,100,000
Investment in unconsolidated affiliates-difference between carrying amount and underlying equity $ 10,600,000 $ 10,600,000 $ 16,300,000
Percentage of ownership underlying net assets50.00%50.00%50.00%
Amortized weighted average remaining useful life2.6
Dividends received from operating activities $ 20,000,000 $ 0 $ 60,000,000 $ 0

Inventories (Details)

Inventories (Details) - USD ($) $ in MillionsSep. 30, 2021Dec. 31, 2020
Inventories
Finished goods $ 314 $ 132.9
Raw materials and semi-finished goods265.5 161.7
Supplies37.8 29.5
Total $ 617.3 $ 324.1

Debt - Schedule of Debt (Detail

Debt - Schedule of Debt (Details) € in Millions, $ in MillionsAug. 27, 2021USD ($)May 03, 2021USD ($)Sep. 30, 2021USD ($)Sep. 30, 2021USD ($)Sep. 30, 2020USD ($)Mar. 24, 2021Dec. 31, 2020USD ($)Feb. 26, 2020USD ($)Feb. 26, 2020EUR (€)Sep. 01, 2017USD ($)
Debt Instruments
Carrying amount $ 2,503.7 $ 2,503.7 $ 1,187.3
Unamortized deferred financing fees(46.7)(46.7)(17)
Total Debt, Less Unamortized Deferred Financing Fees, Current and Noncurrent2,457 2,457 1,170.3
Less: current portion(149.1)(149.1)(12.2)
Total long-term debt, net of unamortized deferred financing fees2,307.9 2,307.9 1,158.1
Repayments on the revolving debt $ 100
Term Loan B [Member]
Debt Instruments
Less: current portion $ (14.5) $ (14.5)
2024 Term Loan B
Debt Instruments
Interest rate at end of period (as a percent)2.081%2.081%
Carrying amount $ 672.1 $ 672.1 677.3
Unamortized deferred financing fees(8.7)(8.7)(10.8)
Total Debt, Less Unamortized Deferred Financing Fees, Current and Noncurrent $ 663.4 $ 663.4 666.5
Less: current portion(7)
2024 Term Loan B | LIBOR [Member]
Debt Instruments
Debt instrument, margin rate2.00%
2028 Term Loan B
Debt Instruments
Interest rate at end of period (as a percent)2.584%2.584%
Carrying amount $ 744.6 $ 744.6
Unamortized deferred financing fees(17.6)(17.6)
Total Debt, Less Unamortized Deferred Financing Fees, Current and Noncurrent727 727
Maximum borrowing capacity $ 750
2028 Term Loan B | LIBOR [Member]
Debt Instruments
Debt instrument, margin rate2.50%
2026 Revolving Facility
Debt Instruments
Funds available for borrowings366.9 366.9
Letters of credit, amount outstanding8.1 $ 8.1
Commitment fee (as a percent)0.375%
Maximum borrowing capacity $ 375 $ 375 $ 375
2029 Senior Notes
Debt Instruments
Interest rate5.125%5.125%5.125%
Carrying amount $ 450 $ 450
Unamortized deferred financing fees(15.1)(15.1)
Total Debt, Less Unamortized Deferred Financing Fees, Current and Noncurrent $ 434.9 $ 434.9
2025 Senior Notes
Debt Instruments
Interest rate5.375%5.375%5.375%5.375%5.375%
Carrying amount $ 500 $ 500 500
Unamortized deferred financing fees(5.3)(5.3)(6.2)
Total Debt, Less Unamortized Deferred Financing Fees, Current and Noncurrent494.7 494.7 493.8 $ 500 € 459.3 $ 500
Accounts Receivable Securitization Facility [Member]
Debt Instruments
Carrying amount130 130 0
Unamortized deferred financing fees0 0 0
Total Debt, Less Unamortized Deferred Financing Fees, Current and Noncurrent130 130 0
Less: current portion(130)(130)
Draw down from (repayments of) credit facility $ 150 (20)
Maximum borrowing capacity150 150
Accounts receivable available to support facility20 20
Other Indebtedness [Member]
Debt Instruments
Carrying amount7 7 10
Total Debt, Less Unamortized Deferred Financing Fees, Current and Noncurrent $ 7 $ 7 $ 10

Debt - Senior Notes (Details)

Debt - Senior Notes (Details) - USD ($) $ in MillionsMay 03, 2021Mar. 24, 2021Sep. 30, 2021Dec. 31, 2020Feb. 26, 2020Sep. 01, 2017
Debt Instruments
Unamortized deferred financing fees $ 46.7 $ 17
2029 Senior Notes
Debt Instruments
Debt instrument issued $ 450
Debt instrument, stated interest rate5.125%5.125%
Unamortized deferred financing fees $ 15.1
Capitalization of issuance costs $ 15.9
Amortization period8 years
2029 Senior Notes | Any Time Prior to August 1, 2015 [Member]
Debt Instruments
Debt instrument, redemption price percentage100.00%
Aggregate principal amount that may be redeemed, as a percent40.00%
Redemption price, as percentage of principal105.125%
2029 Senior Notes | During Any 12-Month Period Commencing from the Issue Date Until August 1, 2015 [Member]
Debt Instruments
Debt instrument, redemption price percentage102.563%
2029 Senior Notes | 12-Month Period Commencing August 1 in Year 2015 [Member]
Debt Instruments
Debt instrument, redemption price percentage101.281%
2029 Senior Notes | 12-Month Period Commencing August 1 in Year 2016 [Member]
Debt Instruments
Debt instrument, redemption price percentage100.00%
2025 Senior Notes
Debt Instruments
Debt instrument, stated interest rate5.375%5.375%5.375%
Unamortized deferred financing fees $ 5.3 $ 6.2
2028 Term Loan B
Debt Instruments
Unamortized deferred financing fees $ 17.6
Capitalization of issuance costs $ 18.7
Amortization period7 years
2028 Term Loan B | LIBOR [Member]
Debt Instruments
Debt instrument, margin rate2.50%

Debt - Senior Credit Facility (

Debt - Senior Credit Facility (Details) - USD ($) $ in MillionsMay 03, 2021Sep. 30, 2021Dec. 31, 2020
Debt Instruments
Current portion $ 149.1 $ 12.2
2022 Revolving Facility
Debt Instruments
Write-off of unamortized deferred financing fees0.5
Unamortized deferred financing fees0.8
2024 Term Loan B
Debt Instruments
Current portion $ 7
2026 Revolving Facility
Debt Instruments
Maximum borrowing capacity $ 375 $ 375
Swingline subfacility capacity25
Letter of credit capacity35
Capitalization of issuance costs $ 0.4
Amortization period5 years
Percentage of Revolving Facility borrowing capacity covenant trigger30.00%
Undrawn letters of credit $ 10
2026 Revolving Facility | Maximum [Member]
Debt Instruments
Net leverage ratio3.50
2028 Term Loan B
Debt Instruments
Maximum borrowing capacity $ 750
Capitalization of issuance costs $ 18.7
Amortization period7 years
Discount rate, as a percent0.50%
Principal payable per quarter, as a percent0.25%
LIBOR [Member] | 2024 Term Loan B
Debt Instruments
Debt instrument, margin rate2.00%
Variable rate floor (as a percent)0.00%
LIBOR [Member] | 2028 Term Loan B
Debt Instruments
Debt instrument, margin rate2.50%
Variable rate floor (as a percent)0.00%

Goodwill (Details)

Goodwill (Details) $ in Millions9 Months Ended
Sep. 30, 2021USD ($)
Goodwill [Roll Forward]
Beginning Balance $ 62.1
Acquisition670.8
Foreign currency impact(13)
Ending Balance719.9
Emulsion Polymers, Latex [Member]
Goodwill [Roll Forward]
Beginning Balance17.1
Foreign currency impact(1)
Ending Balance16.1
Engineered Materials [Member]
Goodwill [Roll Forward]
Beginning Balance16
Acquisition670.8
Foreign currency impact(10.5)
Ending Balance676.3
Base Plastics [Member]
Goodwill [Roll Forward]
Beginning Balance24.2
Foreign currency impact(1.3)
Ending Balance22.9
Polystyrene [Member]
Goodwill [Roll Forward]
Beginning Balance4.8
Foreign currency impact(0.2)
Ending Balance $ 4.6

Derivative Instruments (Details

Derivative Instruments (Details) € in Millions, $ in MillionsFeb. 26, 2020USD ($)Sep. 01, 2017USD ($)Sep. 30, 2021USD ($)itemDec. 31, 2020USD ($)Feb. 26, 2020EUR (€)Apr. 01, 2018USD ($)Mar. 31, 2018USD ($)Sep. 01, 2017EUR (€)
Derivative Instruments
Total debt $ 2,457 $ 1,170.3
Initial excluded component value $ 23.6
Foreign Exchange Forward Contracts [Member]
Derivative Instruments
Derivative term2 months
Foreign Exchange Forward Contracts [Member] | Not Designated as Hedging Instruments [Member]
Derivative Instruments
Derivative contracts, notional amount $ 1,177.9
Foreign Exchange Forward Contracts [Member] | Designated as Hedging Instrument
Derivative Instruments
Derivative contracts, notional amount $ 24
Derivative term3 months
Number of subsidiaries participating | item1
Cross Currency Swap
Derivative Instruments
Derivative contracts, notional amount | € € 420
Derivative term2 years 8 months 12 days5 years
Cross currency swap weighted average interest rate (as a percent)3.672%3.45%
Cumulative translation adjustment, net of tax $ 13.8 $ 38
Cash proceeds $ 51.6
Interest Rate Swap
Derivative Instruments
Derivative contracts, notional amount $ 200
Fixed interest rate per agreement (as a percent)1.81%
LIBOR rate at end of period (as a percent)0.08%
2025 Senior Notes
Derivative Instruments
Total debt $ 500 $ 500 $ 494.7 493.8 € 459.3
Interest rate5.375%5.375%5.375%5.375%5.375%
2024 Term Loan B
Derivative Instruments
Total debt $ 663.4 $ 666.5
2024 Term Loan B | LIBOR [Member]
Derivative Instruments
Debt instrument, margin rate2.00%
Variable rate floor (as a percent)0.00%
Euro [Member] | (Sell)
Derivative Instruments
Derivative contracts, notional amount $ 1,037.4
Chinese Yuan [Member] | (Sell)
Derivative Instruments
Derivative contracts, notional amount38.6
Swiss Franc [Member] | Buy
Derivative Instruments
Derivative contracts, notional amount32.8
Mexico, Pesos | (Sell)
Derivative Instruments
Derivative contracts, notional amount17.8
Korea (South), Won | (Sell)
Derivative Instruments
Derivative contracts, notional amount $ 15.3

Derivative Instruments - Income

Derivative Instruments - Income Statements (Details) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Cost of sales $ 1,101 $ 572.9 $ 2,951.7 $ 1,789.1
Interest expense, net23 10 56.6 32
Gain (Loss) on Derivative Instruments, Net, Pretax(22)
Other expense (income), net(0.1)1.2 8.4 3
Total amounts of income and expense, derivative instruments(22)
Amount of gain (loss) recognized in income, not designated(22)
Cost of Sales
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Cost of sales1,101 572.9 2,951.7 1,789.1
Acquisition purchase price hedge gain
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Gain (Loss) on Derivative Instruments, Net, Pretax(22)
Total amounts of income and expense, derivative instruments(22)
Interest Expense, Net
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Interest expense, net(23)(10)56.6 32
Other Expense (Income), Net [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Other expense (income), net0.1 (1.2)8.4 3
Foreign Exchange Forward Contracts [Member] | Not Designated as Hedging Instruments [Member] | Acquisition purchase price hedge gain
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amount of gain (loss) recognized in income, not designated(22)
Foreign Exchange Forward Contracts [Member] | Not Designated as Hedging Instruments [Member] | Other Expense (Income), Net [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amount of gain (loss) recognized in income, not designated23.3 (13.2)43.4 (7.5)
Foreign Exchange Forward Contracts [Member] | Designated as Hedging Instrument | Cost of Sales
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amount of gain (loss) reclassified from AOCI into income, foreign exchange cash flow hedges0.3 (0.7)
Cross Currency Swap | Interest Expense, Net
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amount of gain excluded from effectiveness testing1.9 1.6 5.5 7
Cross Currency Swap | Other Expense (Income), Net [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amount of gain (loss) recognized in income, not designated(0.8)(0.8)
Interest Rate Swap | Interest Expense, Net
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amount of gain (loss) reclassified from AOCI into income, interest rate cash flow hedges $ (0.9) $ (0.8) $ (2.6) $ (1.6)

Derivative Instruments - Effect

Derivative Instruments - Effect on AOCI (Details) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Derivative Instruments
Gain (Loss) Recognized in AOCI, Cash flow hedges $ 1.2 $ 0.4 $ 5.6 $ (4.6)
Gain (Loss) Recognized in AOCI, Net investment hedges13.1 (24.2)32.1 (11.6)
Foreign Exchange Forward Contracts [Member]
Derivative Instruments
Gain (Loss) Recognized in AOCI, Cash flow hedges0.4 (0.3)3.1 0.6
Cross Currency Swap
Derivative Instruments
Gain (Loss) Recognized in AOCI, Net investment hedges13.1 (24.2)32.1 (11.6)
Interest Rate Swap
Derivative Instruments
Gain (Loss) Recognized in AOCI, Cash flow hedges $ 0.8 $ 0.7 $ 2.5 $ (5.2)

Derivative Instruments - Gains

Derivative Instruments - Gains and Losses in Other expense (Details) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amount of gain (loss) recognized in income, not designated $ (22)
Acquisition purchase price hedge loss(22)
Reclassification expected during next 12 months(2.5)
Other Expense (Income), Net [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Foreign exchange transaction gains (losses) $ (23.7) $ 14 (43) $ 8.9
Derivative, Gain (Loss) on Derivative, Net, Total(0.4)0.8 0.4 1.4
Acquisition purchase price hedge gain
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Acquisition purchase price hedge loss(22)
Foreign Exchange Forward Contracts [Member] | Not Designated as Hedging Instruments [Member] | Other Expense (Income), Net [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amount of gain (loss) recognized in income, not designated $ 23.3 (13.2)43.4 (7.5)
Foreign Exchange Forward Contracts [Member] | Not Designated as Hedging Instruments [Member] | Acquisition purchase price hedge gain
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amount of gain (loss) recognized in income, not designated $ (22)
Cross Currency Swap | Other Expense (Income), Net [Member]
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Amount of gain (loss) recognized in income, not designated $ (0.8) $ (0.8)

Derivative Instruments - Financ

Derivative Instruments - Financial Assets and Liabilities (Details) - USD ($) $ in MillionsSep. 30, 2021Dec. 31, 2020
Derivatives, Financial Assets and Liabilities
Gross derivative asset position $ 23.7 $ 13.2
Counterparty netting, derivative assets(0.1)(6.5)
Net derivative asset position23.6 6.7
Gross derivative liability position(37.9)(82.8)
Counterparty netting, derivative liabilities0.1 6.5
Net derivative liability position(37.8)(76.3)
Total net derivative position(14.2)(69.6)
Accounts Receivable
Derivatives, Financial Assets and Liabilities
Gross derivative asset position23.7 13.2
Accounts Receivable | Arkema
Derivatives, Financial Assets and Liabilities
Derivative assets7.3
Accounts Payable
Derivatives, Financial Assets and Liabilities
Gross derivative liability position(4.2)(13.8)
Other Noncurrent Obligations [Member]
Derivatives, Financial Assets and Liabilities
Gross derivative liability position(33.7)(69)
Foreign Exchange Forward Contracts [Member] | Not Designated as Hedging Instruments [Member]
Derivatives, Financial Assets and Liabilities
Gross derivative asset position18.6 8.2
Counterparty netting, derivative assets(0.1)(6.5)
Net derivative asset position18.5 1.7
Gross derivative liability position(0.8)(8.3)
Counterparty netting, derivative liabilities0.1 6.5
Net derivative liability position(0.7)(1.8)
Total net derivative position17.8 (0.1)
Foreign Exchange Forward Contracts [Member] | Not Designated as Hedging Instruments [Member] | Accounts Receivable
Derivatives, Financial Assets and Liabilities
Gross derivative asset position18.6 8.2
Foreign Exchange Forward Contracts [Member] | Not Designated as Hedging Instruments [Member] | Accounts Payable
Derivatives, Financial Assets and Liabilities
Gross derivative liability position(0.8)(8.3)
Foreign Exchange Forward Contracts [Member] | Designated as Hedging Instrument
Derivatives, Financial Assets and Liabilities
Gross derivative asset position0.9
Net derivative asset position0.9
Gross derivative liability position(2.1)
Net derivative liability position(2.1)
Total net derivative position0.9 (2.1)
Foreign Exchange Forward Contracts [Member] | Designated as Hedging Instrument | Accounts Receivable
Derivatives, Financial Assets and Liabilities
Gross derivative asset position0.9
Foreign Exchange Forward Contracts [Member] | Designated as Hedging Instrument | Accounts Payable
Derivatives, Financial Assets and Liabilities
Gross derivative liability position(2.1)
Interest Rate Swap
Derivatives, Financial Assets and Liabilities
Gross derivative liability position(3.4)(5.9)
Net derivative liability position(3.4)(5.9)
Total net derivative position(3.4)(5.9)
Interest Rate Swap | Accounts Payable
Derivatives, Financial Assets and Liabilities
Gross derivative liability position(3.4)(3.4)
Interest Rate Swap | Other Noncurrent Obligations [Member]
Derivatives, Financial Assets and Liabilities
Gross derivative liability position(2.5)
Cross Currency Swap
Derivatives, Financial Assets and Liabilities
Gross derivative asset position4.2 5
Net derivative asset position4.2 5
Gross derivative liability position(33.7)(66.5)
Net derivative liability position(33.7)(66.5)
Total net derivative position(29.5)(61.5)
Cross Currency Swap | Accounts Receivable
Derivatives, Financial Assets and Liabilities
Gross derivative asset position4.2 5
Cross Currency Swap | Other Noncurrent Obligations [Member]
Derivatives, Financial Assets and Liabilities
Gross derivative liability position $ (33.7) $ (66.5)

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities at Fair Value, Recurring (Details) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Mar. 31, 2020Sep. 30, 2021Sep. 30, 2020Dec. 31, 2020
Fair Value Measurements
Total net derivative position $ (14.2) $ (14.2) $ (69.6)
Impairment loss on assets1.2 3 $ 10.3
Boehlen Location [Member]
Fair Value Measurements
Impairment loss on assets0.3 $ 10.3 2.1
Schkopau PBR Location [Member]
Fair Value Measurements
Impairment loss on assets $ 28
Property Plant And Equipment At Fair Value [Member] | Boehlen Location [Member]
Fair Value Measurements
Assets at fair value, nonrecurring3.5 3.5 3.7
Interest Rate Swap
Fair Value Measurements
Total net derivative position(3.4)(3.4)(5.9)
Cross Currency Swap
Fair Value Measurements
Total net derivative position(29.5)(29.5)(61.5)
Designated as Hedging Instrument | Foreign Exchange Forward Contracts [Member]
Fair Value Measurements
Total net derivative position0.9 0.9 (2.1)
Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]
Fair Value Measurements
Total net derivative position17.8 17.8 (0.1)
Recurring [Member]
Fair Value Measurements
Total net derivative position(14.2)(14.2)(69.6)
Recurring [Member] | Interest Rate Swap
Fair Value Measurements
Liabilities at fair value(3.4)(3.4)(5.9)
Recurring [Member] | Cross Currency Swap
Fair Value Measurements
Assets at fair value4.2 4.2 5
Liabilities at fair value(33.7)(33.7)(66.5)
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value Measurements
Total net derivative position(14.2)(14.2)(69.6)
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Interest Rate Swap
Fair Value Measurements
Liabilities at fair value(3.4)(3.4)(5.9)
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Cross Currency Swap
Fair Value Measurements
Assets at fair value4.2 4.2 5
Liabilities at fair value(33.7)(33.7)(66.5)
Recurring [Member] | Designated as Hedging Instrument | Foreign Exchange Forward Contracts [Member]
Fair Value Measurements
Assets at fair value0.9 0.9
Liabilities at fair value(2.1)
Recurring [Member] | Designated as Hedging Instrument | Significant Other Observable Inputs (Level 2) [Member] | Foreign Exchange Forward Contracts [Member]
Fair Value Measurements
Assets at fair value0.9 0.9
Liabilities at fair value(2.1)
Recurring [Member] | Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]
Fair Value Measurements
Assets at fair value18.5 18.5 1.7
Liabilities at fair value(0.7)(0.7)(1.8)
Recurring [Member] | Not Designated as Hedging Instruments [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign Exchange Forward Contracts [Member]
Fair Value Measurements
Assets at fair value18.5 18.5 1.7
Liabilities at fair value $ (0.7) $ (0.7) $ (1.8)

Fair Value Measurements - Items

Fair Value Measurements - Items not at Fair Value (Details) - USD ($) $ in MillionsSep. 30, 2021Dec. 31, 2020
Significant Other Observable Inputs (Level 2) [Member]
Fair Value of Debt Instruments
Total fair value of long term debt $ 2,378.3 $ 1,187.5
2029 Senior Notes | Significant Other Observable Inputs (Level 2) [Member]
Fair Value of Debt Instruments
Total fair value of long term debt455.5
2028 Term Loan B | Significant Other Observable Inputs (Level 2) [Member]
Fair Value of Debt Instruments
Total fair value of long term debt742.7
2025 Senior Notes | Significant Other Observable Inputs (Level 2) [Member]
Fair Value of Debt Instruments
Total fair value of long term debt509.7 513.5
2024 Term Loan B | Significant Other Observable Inputs (Level 2) [Member]
Fair Value of Debt Instruments
Total fair value of long term debt670.4 $ 674
Accounts Receivable Securitization Facility [Member]
Fair Value of Debt Instruments
Amounts outstanding $ 130

Provision for Income Taxes (Det

Provision for Income Taxes (Details) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Provision for Income Taxes
Effective tax rate6.50%40.10%14.90%126.50%
Provision for income taxes $ 5.5 $ 26.9 $ 48.9 $ 16.2
Change in valuation allowances $ 16.3

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in MillionsSep. 30, 2021USD ($)
Commitments and Contingencies Disclosure
Accrued obligations for environmental remediation and restoration costs $ 5.1

Commitments and Contingencies -

Commitments and Contingencies - Purchase Commitments (Details)9 Months Ended
Sep. 30, 2021
Maximum [Member]
Loss Contingencies [Line Items]
Purchase commitment period7 years
Minimum [Member]
Loss Contingencies [Line Items]
Purchase commitment period1 year

Pension Plans and Other Postr_3

Pension Plans and Other Postretirement Benefits - Net Periodic Benefit Costs (Details) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Net periodic benefit cost
Settlement and curtailment (gain) loss $ (2.3) $ 1.1 $ (2.3) $ 1.1
Net settlement and curtailment loss, Statements of Operations locationOther Nonoperating Income (Expense)Other Nonoperating Income (Expense)Other Nonoperating Income (Expense)Other Nonoperating Income (Expense)
Defined Benefit Pension Plans [Member]
Net periodic benefit cost
Service cost $ 4.2 $ 3.3 $ 12.4 $ 9.8
Interest cost0.4 0.8 1.4 2.2
Expected return on plan assets(0.3)(0.3)(0.6)(0.9)
Amortization of prior service cost (credit)(0.5)(0.3)(0.9)(0.9)
Amortization of net (gain) loss1.6 1 4.7 3.1
Net periodic benefit cost $ 3.1 $ 5.6 $ 14.7 $ 14.4
Interest cost, Statements of Operations locationOther Nonoperating Income (Expense)Other Nonoperating Income (Expense)Other Nonoperating Income (Expense)Other Nonoperating Income (Expense)
Expected return, Statements of Operations locationOther Nonoperating Income (Expense)Other Nonoperating Income (Expense)Other Nonoperating Income (Expense)Other Nonoperating Income (Expense)
Amortization of prior service credit, Statements of Operations locationOther Nonoperating Income (Expense)Other Nonoperating Income (Expense)Other Nonoperating Income (Expense)Other Nonoperating Income (Expense)
Amortization of gain (loss), Statements of Operations locationOther Nonoperating Income (Expense)Other Nonoperating Income (Expense)Other Nonoperating Income (Expense)Other Nonoperating Income (Expense)
Amounts recognized in other comprehensive income (loss)
Net periodic benefit cost $ 3.1 $ 5.6 $ 14.7 $ 14.4
Other Postretirement Benefit Plans [Member] | Maximum [Member]
Net periodic benefit cost
Net periodic benefit cost0.1 0.1 0.1 0.1
Amounts recognized in other comprehensive income (loss)
Net periodic benefit cost $ 0.1 $ 0.1 $ 0.1 $ 0.1

Pension Plans and Other Postr_4

Pension Plans and Other Postretirement Benefits - Net Amounts Recognized (Details) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2021Dec. 31, 2020
Net amounts recognized in the balance sheets at December 31
Noncurrent liabilities $ (298.2) $ (298.2) $ (294.4)
Cash contributions and benefit payments to unfunded plans2.6 6.1
Expected contributions, remainder of current year $ 1.4 $ 1.4

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Expense (Detail) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense $ 4 $ 2.6 $ 11 $ 8.7
Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense2.1 1.5 5.7 4.9
Unrecognized compensation cost13.6 $ 13.6
Weighted-average period of recognition2 years
Option Awards
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense1.2 0.6 $ 3.5 2.3
Unrecognized compensation cost, options4.6 $ 4.6
Weighted-average period of recognition1 year 6 months
Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Share-based compensation expense0.7 $ 0.5 $ 1.8 $ 1.5
Unrecognized compensation cost $ 3.7 $ 3.7
Weighted-average period of recognition1 year 10 months 24 days

Share-Based Compensation - RSUs

Share-Based Compensation - RSUs (Details) - Restricted Stock Units [Member]9 Months Ended
Sep. 30, 2021$ / sharesshares
Other-than-Options, Shares Activity
Granted, Shares | shares212,167
Other-than-Options, FV Activity
Granted, Weighted-Average Grant Date Fair Value per Share | $ / shares $ 58.59

Share-Based Compensation - Opti

Share-Based Compensation - Options and PSUs (Details) - USD ($) $ / shares in Units, $ in Millions9 Months Ended
Sep. 30, 2021Sep. 30, 2020
Options, Additional Disclosures
Proceeds from exercise of option awards $ 10.5 $ 0.4
Option Awards
Options Outstanding Roll Forward
Granted, Options296,354
Options, Additional Disclosures
Unrecognized compensation cost, options $ 4.6
Fair Value Assumptions
Expected term (in years)5 years 6 months
Expected volatility48.69%
Risk-free interest rate0.78%
Dividend yield1.81%
Options granted, Weighted average grant date fair value $ 22.61
Performance Share Units
Fair Value Assumptions
Expected term (in years)3 years
Expected volatility58.00%
Risk-free interest rate0.20%
Share Price $ 61.06
Other-than-Options, Shares Activity
Granted, Shares49,463
Other-than-Options, FV Activity
Granted, Weighted-Average Grant Date Fair Value per Share $ 61.06

Segments - Reconciliation of Se

Segments - Reconciliation of Segment Reporting to Consolidated (Details) $ in MillionsOct. 01, 2020segmentSep. 30, 2021USD ($)Sep. 30, 2020USD ($)Sep. 30, 2021USD ($)segmentSep. 30, 2020USD ($)Dec. 31, 2020USD ($)
Segment Reporting Information [Line Items]
Number of operating segments unchanged | segment4
Number of new operating segments | segment2
Sales to external customers $ 1,269.3 $ 679.2 $ 3,529 $ 1,976.5
Equity in earnings of unconsolidated affiliates17.1 18.3 70.2 42.5
Adjusted EBITDA198.4 117.4 668 211.6
Investment in unconsolidated affiliates250.3 250.3 $ 240.1
Depreciation and amortization111 69.8
Capital expenditures64.7 47.4
Operating Segments [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization49.8 21.2 111 69.8
Emulsion Polymers, Latex [Member]
Segment Reporting Information [Line Items]
Sales to external customers315.6 183.2 877.6 567.3
Adjusted EBITDA37.1 18.7 86.2 55.4
Base Plastics [Member]
Segment Reporting Information [Line Items]
Sales to external customers393.3 240.1 1,119.3 649.1
Adjusted EBITDA87.9 40.5 235 55.6
Engineered Materials [Member]
Segment Reporting Information [Line Items]
Sales to external customers230.8 50 477.5 135.2
Adjusted EBITDA32.7 9.4 68.5 22.3
Polystyrene [Member]
Segment Reporting Information [Line Items]
Sales to external customers274.8 167.3 855 505.9
Adjusted EBITDA51.2 20.4 149.6 46.4
Feedstocks [Member]
Segment Reporting Information [Line Items]
Sales to external customers54.8 38.6 199.6 119
Adjusted EBITDA $ (27.6)10.1 $ 58.5 (10.6)
Americas Styrenics [Member]
Segment Reporting Information [Line Items]
Percentage of ownership underlying net assets50.00%50.00%
Adjusted EBITDA $ 17.1 $ 18.3 $ 70.2 $ 42.5
AmSty [Member]
Segment Reporting Information [Line Items]
Percentage of ownership underlying net assets50.00%50.00%50.00%
Investment in unconsolidated affiliates $ 250.3 $ 250.3 $ 240.1

Segments - Recon. of Net Income

Segments - Recon. of Net Income to Segment Adjusted EBITDA (Details) - USD ($) $ in MillionsSep. 01, 2021May 03, 2021Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Segment Reporting Information [Line Items]
Income from continuing operations before income taxes $ 84.9 $ 67.1 $ 327.1 $ 12.8
Interest expense, net(23)(10)(56.6)(32)
Depreciation and amortization111 69.8
Adjusted EBITDA addbacks15.7 2.5 102 40.9
Adjusted EBITDA198.4 117.4 668 211.6
Net (gain) loss on disposition of businesses and assets(0.2)(0.4)
Restructuring and other charges0.2 (0.1)6.8 7
Acquisition transactions and integration net costs (benefit)13.6 62.8 (0.3)
Acquisition purchase price hedge gain22
Asset impairment charges or write-offs1.2 3 10.3
Other items0.7 2.6 7.6 24.3
Acquisition-related costs10.1 44.7
Inventory adjustment13.6
Arkema
Segment Reporting Information [Line Items]
Acquisition-related costs0.2 20
Inventory adjustment $ 10.1
Jurisdictional asset transfer taxes4.5
Aristech Surfaces L L C [Member]
Segment Reporting Information [Line Items]
Acquisition-related costs3.1 3.4
Inventory adjustment $ 6.9 3.5
Operating Segments [Member]
Segment Reporting Information [Line Items]
Income from continuing operations before income taxes84.9 67.1 327.1 12.8
Interest expense, net23 10 56.6 32
Depreciation and amortization49.8 21.2 111 69.8
Corporate Unallocated [Member]
Segment Reporting Information [Line Items]
Corporate Unallocated $ 25 $ 16.6 $ 71.3 $ 56.1

Restructuring (Details)

Restructuring (Details) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring Charges $ 0.2 $ (0.1) $ 6.4 $ 9.5
Deferred taxes on land held for sale81.3 81.3 $ 42.2
Restructuring Reserve [Roll Forward]
Accrued charges/Balance at beginning of period8
Expenses6.8
Payments/Deductions(5.5)
Accrued charges/Balance at end of period9.3 9.3
Corporate Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges(0.1)(0.3)9
Cumulative life-to-date charges25.4 25.4
Transformational Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges0.3 6.4
Cumulative life-to-date charges6.4 6.4
Other Restructurings
Restructuring Cost and Reserve [Line Items]
Restructuring Charges0.2 0.5
Accelerated Depreciation | Corporate Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges(0.4)2.5
Cumulative life-to-date charges2.5 2.5
Employee Termination Benefit Charges [Member]
Restructuring Reserve [Roll Forward]
Accrued charges/Balance at beginning of period7.9
Expenses6.8
Payments/Deductions(5.4)
Accrued charges/Balance at end of period9.3 9.3
Employee Termination Benefit Charges [Member] | Corporate Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges(0.1)(0.5)0.4 3.9
Cumulative life-to-date charges19.9 19.9
Employee Termination Benefit Charges [Member] | Transformational Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges0.3 6.4
Cumulative life-to-date charges6.4 6.4
Employee Termination Benefit Charges [Member] | Transformational Restructuring Program [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges1 1
Contract Termination Charges [Member]
Restructuring Reserve [Roll Forward]
Accrued charges/Balance at beginning of period0.1
Payments/Deductions(0.1)
Contract Termination Charges [Member] | Corporate Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges2.4
Cumulative life-to-date charges2.8 2.8
Other Restructuring | Corporate Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges $ 0.2 $ 0.2
Cumulative life-to-date charges $ 0.2 $ 0.2

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) - Components (Details) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Sep. 30, 2020Sep. 30, 2021Sep. 30, 2020
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period $ 829.8 $ 458.8 $ 590.3 $ 668.9
Balance at end of period922 547.6 922 547.6
Currency Translation Adjustment, Net [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period(109.3)(97.1)(109)(106.7)
Other comprehensive income (loss)(1.7)(6.7)(2)2.9
Balance at end of period(111)(103.8)(111)(103.8)
Employee Benefits, Net [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period(69.8)(54.6)(71.9)(56.3)
Other comprehensive income (loss)9.3 0.1 9.3 0.7
Amounts reclassified from AOCI to net income(1.2)1.6 0.9 2.7
Balance at end of period(61.7)(52.9)(61.7)(52.9)
Accumulated Gain Loss Net Cash Flow Hedge Parent
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period(0.8)(4.4)(5.2)0.6
Other comprehensive income (loss)0.6 (1.1)3 (6.2)
Amounts reclassified from AOCI to net income0.6 1.5 2.6 1.6
Balance at end of period0.4 (4)0.4 (4)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at beginning of period(179.9)(156.1)(186.1)(162.4)
Other comprehensive income (loss)8.2 (7.7)10.3 (2.6)
Amounts reclassified from AOCI to net income(0.6)3.1 3.5 4.3
Balance at end of period $ (172.3) $ (160.7) $ (172.3) $ (160.7)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Loss) - Reclassification (Details) - USD ($) $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Jun. 30, 2021Mar. 31, 2021Sep. 30, 2020Jun. 30, 2020Mar. 31, 2020Sep. 30, 2021Sep. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales $ 1,101 $ 572.9 $ 2,951.7 $ 1,789.1
Interest expense, net23 10 56.6 32
Settlement and curtailment (gain) loss(2.3)1.1 (2.3)1.1
Income before income taxes(84.9)(67.1)(327.1)(12.8)
Provision for income taxes5.5 26.9 48.9 16.2
Net income(93.1) $ (151.6) $ (71.5)(105.8) $ 128.4 $ 36.3 (316.2)58.8
Employee Benefits, Net [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes(1)2 2.1 3.7
Provision for income taxes(0.2)(0.4)(1.2)(1)
Net income(1.2)1.6 0.9 2.7
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Prior service credit(0.2)(0.3)(0.7)(0.9)
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net actuarial loss1.7 1.2 5.3 3.5
Settlement and curtailment (gain) loss(2.5)1.1 (2.5)1.1
Accumulated Gain Loss Net Cash Flow Hedge Parent | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales(0.3)0.7
Interest expense, net0.9 0.8 2.6 1.6
Income before income taxes0.6 1.5 2.6 1.6
Net income $ 0.6 $ 1.5 $ 2.6 $ 1.6

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions3 Months Ended9 Months Ended
Sep. 30, 2021Jun. 30, 2021Mar. 31, 2021Sep. 30, 2020Jun. 30, 2020Mar. 31, 2020Sep. 30, 2021Sep. 30, 2020
Earnings:
Net income from continuing operations $ 79.4 $ 40.2 $ 278.2 $ (3.4)
Net income (loss) from discontinued operations, net of income taxes13.7 65.6 38 (55.4)
Net income (loss) $ 93.1 $ 151.6 $ 71.5 $ 105.8 $ (128.4) $ (36.3) $ 316.2 $ (58.8)
Shares:
Weighted average ordinary shares outstanding38.8 38.3 38.7 38.4
Dilutive effect of RSUs, option awards and PSUs0.7 0.1 0.9
Diluted weighted average ordinary shares outstanding39.5 38.4 39.6 38.4
Income (loss) per share:
Net income (loss) per share- basic, continuing $ 2.04 $ 1.05 $ 7.19 $ (0.09)
Net income (loss) per share- basic, discontinued operations0.351.720.98(1.44)
Net income (loss) per share- basic2.392.778.17(1.53)
Net income (loss) per share- diluted, continuing2.011.047.03(0.09)
Net income (loss) per share- diluted, discontinued operations0.351.710.96(1.44)
Net income (loss) per share- diluted $ 2.36 $ 2.75 $ 7.99 $ (1.53)
Anti-dilutive shares excluded0.6 1.6 0.6