Document and Entity Information Document - shares	3 Months Ended
	Jun. 30, 2018	Aug. 13, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	CARVER BANCORP INC
Entity Central Index Key	0001016178
Current Fiscal Year End Date	--03-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		3,698,664
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes