Basis of Financial Statement Presentation - Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money markets, Carrying Value	$ 67,325	$ 83,891
Total debt, Carrying Value	(320,223)	(324,623)
Certificates of Deposit, at carrying value	31,700	33,900
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt, Fair Value	(336,842)	(343,125)
Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt, Fair Value	0	0
Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt, Fair Value	(336,842)	(343,125)
Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt, Fair Value	0	0
Money markets | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money markets, Fair Value Measurement	67,325	83,891
Money markets | Level 1 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money markets, Fair Value Measurement	67,325	83,891
Money markets | Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money markets, Fair Value Measurement	0	0
Money markets | Level 3 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money markets, Fair Value Measurement	$ 0	$ 0