Debt - Interest Income and Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Interest expense
Contractual interest expense	$ 19,471	$ 30,323	$ 38,825
Capitalized interest	(232)	(141)	(154)
Amortization of debt issuance costs	334	511	1,390
Amortization of debt (premium) discount	1,481	1,843	(788)
Imputed interest on acquisition related obligations	57	113	159
Interest expense on capital leases	128	233	323
Total interest expense	$ 21,239	$ 32,882	$ 39,755