Related Party Transactions (Related Party Assets) (Details) - USD ($) $ in Thousands		Jun. 30, 2015	Mar. 31, 2015
Related party assets:
Related party assets		$ 134,653	$ 141,790
Private Mini [Member]
Related party assets:
U-Haul notes, receivables and interest		59,259	59,375
Sac Holdings [Member]
Related party assets:
Notes receivable		50,167	50,428
U-Haul interest receivable		4,660	4,579
U-Haul receivables		18,482	20,108
Mercury [Member]
Related party assets:
U-Haul receivables		3,549	6,667
Insurance Group [Member]
Related party assets:
Other	[1]	$ (1,464)	$ 633

[1] Timing differences for intercompany balances with insurance subsidiaries resulting from the three month difference in reporting periods.