| Document and Entity Information | Aug. 19, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Aug. 19, 2024 |
| Entity File Number | 1-07265 |
| Entity Registrant Name | AMBASE CORPORATION |
| Entity Central Index Key | 0000020639 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 95-2962743 |
| Entity Address, Address Line One | 7857 WEST SAMPLE ROAD, SUITE 134 |
| Entity Address, City or Town | CORAL SPRINGS |
| Entity Address, State or Province | FL |
| Entity Address, Postal Zip Code | 33065 |
| City Area Code | 201 |
| Local Phone Number | 265-0169 |
| Entity Emerging Growth Company | false |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
