| Document and Entity Information | Oct. 01, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 01, 2023 |
| Entity File Number | 001-13007 |
| Entity Registrant Name | CARVER BANCORP, INC. |
| Entity Central Index Key | 0001016178 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 13-3904174 |
| Entity Address, Address Line One | 75 West 125th Street |
| Entity Address, City or Town | New York |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10027-4512 |
| City Area Code | 212 |
| Local Phone Number | 360-8820 |
| Title of 12(b) Security | Common stock, par value $0.01 per share |
| Trading Symbol | CARV |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
