Borrowings (Components of Interest Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Interest expense, borrowings:
Interest expense	$ 41,600	$ 44,743	$ 83,511	$ 88,074
Capitalized interest	(3,494)	(6,669)	(7,928)	(12,168)
Amortization of transaction costs	1,458	1,047	2,755	2,100
Interest expense resulting from derivatives	961	1	1,708	4
Total interest expense	$ 40,525	$ 39,122	$ 80,046	$ 78,010