Earnings (Loss) Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended							12 Months Ended
	Mar. 31, 2014	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Earnings (Loss) Per Common Share [Abstract]
Net (loss) / income attributable to Carver Bancorp, Inc.	$ (769)	$ 342	$ 414	$ 687	$ 474	$ (138)	$ (361)	$ (836)	$ 662	$ (23,407)
Dividends, Preferred Stock								0	0	(288)
Net Income (Loss) available to common shareholders								$ (836)	$ 662	$ (23,695)
Weighted Average Number of Shares Outstanding, Basic								3,696,000	3,696,000	1,662,000
Weighted Average Number Diluted Shares Outstanding Adjustment								1,000	1,000	0
Weighted Average Number of Common Shares Outstanding, Diluted								3,697,000	3,697,000	1,662,000
Earnings Per Share, Basic	$ (0.21)	$ 0.09	$ 0.11	$ 0.19	$ 0.13	$ (0.04)	$ (0.10)	$ (0.23)	$ 0.18	$ (14.26)
Earnings Per Share, Diluted	$ (0.21)	$ 0.09	$ 0.11	$ 0.19	$ 0.13			$ (0.23)	$ 0.18	$ (14.26)