Related Party Transactions (Related Party Costs and Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Related Party Cost and Expense [Abstract]
Related party expenses, total	$ 71,824	$ 64,697	$ 64,112
Blackwater [Member]
Related Party Cost and Expense [Abstract]
U-Haul lease expenses	2,612	2,631	2,678
U-Haul commission expenses	$ 69,212	$ 62,066	$ 61,434