Financial Instruments with Potential Credit Risk, Cash Deposits (Details) (USD $)	Mar. 31, 2013
Cash, Insured and Uninsured [Abstract]
Cash, FDIC insured amount	$ 250,000
Cash, CDIC insured amount	$ 100,000

The insured amount by Canadian financial institutions. It is insured by the Canada Deposit Insurance Corporation ("CDIC"). This is the maximum amount issued by this institution.

No definition available.

Name:	uhal_CashCdicInsuredAmount
Namespace Prefix:	uhal_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant