Borrowings (Interest Rates and Company Borrowings) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Interest and debt expense:
Weighted average interest rate during the quarter	3.32%	1.39%	2.66%	1.38%
Interest rate at quarter end	3.80%	1.38%	3.80%	1.38%
Maximum amount outstanding during the quarter	$ 1,102,000	$ 1,093,000	$ 1,105,000	$ 1,093,000
Average amount outstanding during the quarter	877,522	1,090,283	984,464	1,081,716
Facility fees	$ 111	$ 61	$ 169	$ 131