Carver Bancorp Inc.-Parent Company Only Parent Company Statements of Cash Flow (Details) (USD $)	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2003
Net Income (Loss) Attributable to Parent	$ (836,000)	$ 662,000	$ (23,407,000)
Increase (decrease) in other assets	207,000	(20,000)	(1,602,000)
Increase (decrease) in other liabilities	(563,000)	(268,000)	1,113,000
Net Cash Provided by (Used in) Operating Activities	15,546,000	20,341,000	31,528,000
Net Cash Provided by (Used in) Investing Activities	(5,289,000)	(3,485,000)	62,338,000
Treasury Stock, Value, Acquired, Cost Method	(5,000)	(5,000)	81,000
Proceeds from (Payments for) Other Financing Activities	(6,000,000)	32,974,000	(69,212,000)	400,000
Net cash (used in) provided by financing activities	7,651,000	(3,907,000)	(46,246,000)
Cash and Cash Equivalents, Period Increase (Decrease)	17,908,000	12,949,000	47,620,000
Parent Company [Member]
Net Income (Loss) Attributable to Parent	(836,000)	662,000	(23,407,000)
Income (Loss) from Subsidiaries, before Tax	14,000	1,561,000	(21,779,000)
Increase (Decrease) Due from Affiliates	(3,000)	(1,000)	(160,000)
Increase (decrease) in other assets	(18,000)	(9,000)	(28,000)
Increase (decrease) in accounts payable to subsidiaries	422,000	399,000	(693,000)
Increase (decrease) in other liabilities	461,000	386,000	(17,000)
Other, net	3,000	33,000	(159,000)
Net Cash Provided by (Used in) Operating Activities	15,000	(91,000)	(2,685,000)
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	0	0	247,000
Proceeds from Issuance of Convertible Preferred Stock	0	0	51,432,000
Net Cash Provided by (Used in) Investing Activities	0	0	51,679,000
Debt Instrument, Increase, Additional Borrowings	0	0	(113,000)
Treasury Stock, Value, Acquired, Cost Method	0	(30,000)	(122,000)
Proceeds from (Payments for) Other Financing Activities	0	0	(44,000,000)
Net cash (used in) provided by financing activities	0	(30,000)	(44,235,000)
Cash and Cash Equivalents, Period Increase (Decrease)	15,000	(121,000)	4,759,000
Cash - beginning	4,654,000	4,775,000	16,000
Cash - end	$ 4,669,000	$ 4,654,000	$ 4,775,000