Interest on Borrowings (Interest Rates and Company Borrowings) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Interest and debt expense:
Weighted average interest rate during the year	1.67%	1.70%	1.10%
Interest rate at year end	1.82%	1.65%	1.78%
Maximum amount outstanding during the year	$ 347,000	$ 232,000	$ 89,632
Average amount outstanding during the year	237,372	187,004	18,658
Facility fees	$ 201	$ 336	$ 301