Related Party Transactions (Related Party Costs and Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Related party cost and expense:
Related party expenses, total	$ 21,191	$ 19,275	$ 37,180	$ 37,135
Blackwater [Member]
Related party cost and expense:
U-Haul lease expenses	658	658	1,315	1,316
U-Haul commission expenses	$ 20,533	$ 18,617	$ 35,865	$ 35,819