Carver Bancorp Inc.-Parent Company Only Carver Bancorp Cash Flow (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Jun. 30, 2011	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2003	Mar. 31, 2010
Net loss before attribution of noncontrolling interests		$ (283)	$ (22,778)	$ (39,470)
Increase (Decrease) in Other Operating Assets		(20)	(1,602)	643
Increase (Decrease) in Other Operating Liabilities		(268)	1,112	613
Net Cash Provided by (Used in) Operating Activities		20,341	31,527	4,307
Proceeds from Issuance of Convertible Preferred Stock	55,000
Net Cash Provided by (Used in) Investing Activities		(3,485)	62,338	55,637
Treasury Stock, Value, Acquired, Cost Method		(5)	81
Dividends paid		0	(364)	712
Proceeds from (Payments for) Other Financing Activities		32,974	(69,212)	(19,029)	400
Net cash (used in) provided by financing activities		(3,907)	(46,246)	(54,213)
Cash and Cash Equivalents, Period Increase (Decrease)		12,949	47,619	5,731
Cash and Cash Equivalents, at Carrying Value		104,646	91,697	44,077		38,346
Parent Company [Member]
Net loss before attribution of noncontrolling interests		662	(23,407)	(39,527)
income from subsidiaries		1,561	(21,779)	(37,872)
Increase (Decrease) in Income Taxes Payable, Net of Income Taxes Receivable		0	0	0
Increase (Decrease) in Accounts Receivable		(1)	(160)	0
Increase (Decrease) in Other Operating Assets		(9)	(28)	49
Increase (Decrease) in Accounts Payable		399	(693)	690
Increase (Decrease) in Other Operating Liabilities		386	(17)	260
Proceeds from Other Operating Activities		33	(159)	1,212
Net Cash Provided by (Used in) Operating Activities		(91)	(2,685)	556
Dividends		0	247	0
Proceeds from Issuance of Convertible Preferred Stock		0	51,432	0
Net Cash Provided by (Used in) Investing Activities		0	51,679	0
Debt Instrument, Increase, Additional Borrowings		0	(113)	113
Treasury Stock, Value, Acquired, Cost Method		(30)	(122)	0
Dividends paid		0	0	(712)
Proceeds from (Payments for) Other Financing Activities		0	(44,000)	0
Net cash (used in) provided by financing activities		(30)	(44,235)	(599)
Cash and Cash Equivalents, Period Increase (Decrease)		(121)	4,759	(43)
Cash and Cash Equivalents, at Carrying Value		$ 4,654	$ 4,775	$ 16		$ 59