Debt - Interest Income and Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Interest expense
Contractual interest expense	$ 30,323	$ 38,825	$ 39,087
Capitalized interest	(141)	(154)	(509)
Amortization of debt issuance costs	511	1,390	1,392
Amortization of debt (premium) discount	1,843	(788)	(745)
Imputed interest on acquisition related obligations	113	159	212
Interest expense on capital leases	233	323	168
Total interest expense	$ 32,882	$ 39,755	$ 39,605