Related Party Transactions (Related Party Costs and Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Related party cost and expense:
Related party expenses, total	$ 17,812	$ 16,980	$ 34,253	$ 32,605
Sac Holdings [Member]
Related party cost and expense:
U-Haul lease expenses	684	654	1,372	1,308
U-Haul commission expenses	16,007	15,268	30,708	29,259
Private Mini [Member]
Related party cost and expense:
U-Haul commission expenses	$ 1,121	$ 1,058	$ 2,173	$ 2,038