Related Party Transactions (Related Party Costs and Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Related party cost and expense:
Related party expenses, total	$ 27,147	$ 21,191	$ 50,653	$ 37,180
Blackwater [Member]
Related party cost and expense:
U-Haul lease expenses	611	658	1,237	1,315
U-Haul commission expenses	$ 26,536	$ 20,533	$ 49,416	$ 35,865