Interest on Borrowings (Components of interest expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Interest expense, borrowings:
Interest expense	$ 165,484	$ 180,444	$ 150,609
Capitalized interest	(11,573)	(23,517)	(12,733)
Amortization of transaction costs	5,949	4,427	3,745
Interest expense resulting rom derivatives	3,642	(404)	824
Total interest expense	$ 163,502	$ 160,950	$ 142,445