Document and Entity Information Document - shares	9 Months Ended
	Dec. 31, 2019	Feb. 11, 2020
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	Dec. 31, 2019
Document Fiscal Year Focus	1905
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		3,699,505
Entity Shell Company	false
Entity Smaller Reporting Company	true
Entity Emerging Growth Company	false
Document Quarterly Report	true
Document Transition Report	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes