Document and Entity Information
Document and Entity Information - shares | 6 Months Ended | |
Jun. 30, 2020 | Jul. 31, 2020 | |
Cover [Abstract] | ||
Document Type | 10-Q/A | |
Document Quarterly Report | true | |
Document Period End Date | Jun. 30, 2020 | |
Document Transition Report | false | |
Entity File Number | 0-21719 | |
Entity Registrant Name | Steel Dynamics, Inc | |
Entity Incorporation, State or Country Code | IN | |
Entity Tax Identification Number | 35-1929476 | |
Entity Address, Address Line One | 7575 West Jefferson Blvd | |
Entity Address, City or Town | Fort Wayne | |
Entity Address, State or Province | IN | |
Entity Address, Postal Zip Code | 46804 | |
City Area Code | 260 | |
Local Phone Number | 969-3500 | |
Title of 12(b) Security | Common Stock | |
Trading Symbol | STLD | |
Security Exchange Name | NASDAQ | |
Entity Current Reporting Status | Yes | |
Entity Interactive Data Current | Yes | |
Entity Filer Category | Large Accelerated Filer | |
Entity Small Business | false | |
Entity Emerging Growth Company | false | |
Entity Shell Company | false | |
Entity Common Stock, Shares Outstanding | 210,364,813 | |
Entity Central Index Key | 0001022671 | |
Current Fiscal Year End Date | --12-31 | |
Document Fiscal Year Focus | 2020 | |
Document Fiscal Period Focus | Q2 | |
Amendment Flag | false |