| Document and Entity Information | Oct. 27, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 27, 2020 |
| Entity Registrant Name | Associated Capital Group, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 1-37387 |
| Entity Tax Identification Number | 00-0000000 |
| Entity Address, Address Line One | ONE CORPORATE CENTER |
| Entity Address, City or Town | RYE |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10580 |
| City Area Code | 203 |
| Local Phone Number | 629-9595 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | true |
| Entity Central Index Key | 0001642122 |
| Title of 12(b) Security | Class A Common Stock, par value $0.001 per share |
| Trading Symbol | AC |
| Security Exchange Name | NYSE |
