Debt - Interest Income and Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Interest expense
Contractual interest expense	$ 38,825	$ 39,087	$ 38,953
Capitalized interest	(154)	(509)	(237)
Amortization of debt issuance costs	1,390	1,392	1,480
Amortization of debt (premium) discount	(788)	(745)	(407)
Amortization of Acquisition Costs	159	212	741
Capital Leases, Income Statement, Interest Expense	323	168	171
Total interest expense	$ 39,755	$ 39,605	$ 40,701