Document and Entity Information Document - shares	6 Months Ended
	Sep. 30, 2019	Nov. 12, 2019
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	Sep. 30, 2019
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		3,699,384
Entity Shell Company	false
Entity Smaller Reporting Company	true
Entity Emerging Growth Company	false
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes