Related Party Transactions (Related Party Costs and Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Related Party Cost and Expense [Abstract]
Related party expenses, total	$ 59,853	$ 57,368	$ 54,709
Sac Holdings [Member]
Related Party Cost and Expense [Abstract]
U-Haul lease expenses	2,740	2,648	2,618
U-Haul commission expenses	53,334	51,036	48,833
Private Mini [Member]
Related Party Cost and Expense [Abstract]
U-Haul commission expenses	$ 3,779	$ 3,684	$ 3,258