Related Party Transactions (Related Party Costs and Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Related Party Cost and Expense [Abstract]
Related party expenses, total	$ 61,279	$ 59,853	$ 57,368
Blackwater [Member]
Related Party Cost and Expense [Abstract]
U-Haul lease expenses	2,684	2,740	2,648
U-Haul commission expenses	$ 58,595	$ 57,113	$ 54,720