Related Party Notes Receivable and Management Fees [Text] (Details) (USD $)			3 Months Ended		6 Months Ended
	Sep. 30, 2014 Sac Holdings [Member]	Mar. 31, 2014 Sac Holdings [Member]	Sep. 30, 2014 Various Subsidiaries of Amerco [Member] Sac Holdings [Member]	Sep. 30, 2013 Various Subsidiaries of Amerco [Member] Sac Holdings [Member]	Sep. 30, 2014 Various Subsidiaries of Amerco [Member] Sac Holdings [Member]	Sep. 30, 2013 Various Subsidiaries of Amerco [Member] Sac Holdings [Member]	Sep. 30, 2014 Amerco, Uhaul Intl [Member] Private Mini [Member]	Sep. 30, 2013 Amerco, Uhaul Intl [Member] Private Mini [Member]	Sep. 30, 2014 AMERCO [Member] Sac Holdings, Mercury, Four Sac, Five Sac, Galaxy and Private Mini [Member]	Sep. 30, 2013 AMERCO [Member] Sac Holdings, Mercury, Four Sac, Five Sac, Galaxy and Private Mini [Member]
Related party notes receivable:
Cash interest payments					$ 3,300,000	$ 13,900,000	$ 2,700,000	$ 2,700,000
Notes receivable outstanding	70,984,000	71,464,000	71,000,000		71,000,000		65,300,000
Largest aggregate balance in reporting period			71,500,000		71,500,000		65,500,000
One time cash interest proceeds				10,400,000
Related party repayments and interest receivables					20,200,000		9,000,000
Earliest maturity year			2017	2017
Management fees revenue:
Management fees received exclusive of reimbursed expenses									$ 15,200,000	$ 15,700,000
Management fee rate, lowest									4.00%
Management fee rate, highest									10.00%