Carver Bancorp Inc.-Parent Company Only-Condensed Statements of Financial Condition (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Condensed Balance Sheet Statements, Captions [Line Items]
Other assets	$ 7,156	$ 5,287
Total assets	735,314	676,748
Other liabilities	21,768	14,663
Total liabilities	680,227	624,447
Stockholders' Equity Attributable to Parent	55,087	52,301	$ 48,894
Total liabilities and equity	735,314	676,748
Parent Company
Condensed Balance Sheet Statements, Captions [Line Items]
Cash on deposit with subsidiaries	1,433	12,374	$ 496
Investment in subsidiaries	70,646	63,871
Other assets	66	363
Total assets	72,145	76,608
Borrowings	15,903	13,403
Accounts payable to subsidiaries	499	7,656
Other liabilities	656	3,248
Total liabilities	17,058	24,307
Stockholders' Equity Attributable to Parent	55,087	52,301
Total liabilities and equity	$ 72,145	$ 76,608