Related Party Notes Receivable and Management Fees [Text] (Details) (USD $)			3 Months Ended
	Jun. 30, 2013 SAC Holdings	Mar. 31, 2013 SAC Holdings	Jun. 30, 2013 Various Subsidiaries of Amerco SAC Holdings	Jun. 30, 2012 Various Subsidiaries of Amerco SAC Holdings	Jun. 30, 2013 Amerco, U-Haul Int'l Private Mini	Jun. 30, 2012 Amerco, U-Haul Int'l Private Mini	Jun. 30, 2013 AMERCO SAC Holdings, Mercury, Four SAC, Five SAC, Galaxy and Private Mini	Jun. 30, 2012 AMERCO SAC Holdings, Mercury, Four SAC, Five SAC, Galaxy and Private Mini
Related party notes receivable:
Cash interest payments			$ 12,300,000	$ 7,200,000	$ 1,400,000	$ 1,400,000
Notes receivable outstanding	72,181,000	72,397,000			65,800,000
Largest aggregate balance in reporting period			72,400,000		65,900,000
Earliest maturity year			2017	2017
Latest maturity year			2019	2019
Management fees revenue:
Management fees received exclusive of reimbursed expenses							$ 10,300,000	$ 9,400,000
Management fee rate, lowest							4.00%	4.00%
Management fee rate, highest							10.00%	10.00%