Maximum Amount of Life Insurance Retained on Any One Life (Details) (USD $)	12 Months Ended
Mar. 31, 2013
Reinsurance Disclosures [Abstract]
Maximum amount of life insurance retained on any one life	$ 110,000

During their normal course of business, our insurance subsidiaries assume and cede reinsurance on both a coinsurance and a risk premium basis. They also obtain reinsurance for that portion of risks exceeding their retention limits. This concept provides the maximum amount of life insurance retained on any one life by these insurance subsidiaries.

No definition available.

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Namespace Prefix:	uhal_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration