Related Party Assets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012		Mar. 31, 2012
Related party assets:
Other	$ (926)	[1]	$ (226)	[1]
Related party assets	175,175		316,157
SAC Holdings
Related party assets:
Notes receivable	72,634		195,426
U-Haul interest receivable	14,407		18,667
U-Haul receivables	14,753		30,297
Private Mini
Related party assets:
U-Haul notes, receivables and interest	70,706		68,798
Mercury
Related party assets:
U-Haul receivables	$ 3,601		$ 3,195

[1] Timing difference from intercompany balances with insurance subsidiaries