Document and Entity Information
Document and Entity Information - shares | Mar. 31, 2021 | Apr. 30, 2021 |
Cover [Abstract] | ||
Document Type | 10-Q/A | |
Amendment Flag | false | |
Document Quarterly Report | true | |
Document Period End Date | Mar. 31, 2021 | |
Current Fiscal Year End Date | --12-31 | |
Document Transition Report | false | |
Entity Registrant Name | GAMCO INVESTORS, INC. ET AL | |
Entity Incorporation, State or Country Code | DE | |
Entity File Number | 001-14761 | |
Entity Tax Identification Number | 13-4007862 | |
Entity Address, Address Line One | 191 Mason Street | |
Entity Address, City or Town | Greenwich | |
Entity Address, State or Province | CT | |
Entity Address, Postal Zip Code | 06830 | |
City Area Code | 203 | |
Local Phone Number | 629-2726 | |
Entity Filer Category | Accelerated Filer | |
Entity Current Reporting Status | Yes | |
Entity Interactive Data Current | Yes | |
Entity Emerging Growth Company | false | |
Entity Shell Company | false | |
Entity Small Business | true | |
Entity Common Stock, Shares Outstanding | 8,290,951 | |
Document Fiscal Year Focus | 2021 | |
Document Fiscal Period Focus | Q1 | |
Entity Central Index Key | 0001060349 | |
Title of 12(b) Security | Class A Common Stock, $0.001 par value | |
Trading Symbol | GBL | |
Security Exchange Name | NYSE |