Basis of Financial Statement Presentation - ASC 606 Adjustment Cash Flow (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2019		Sep. 30, 2018		Sep. 30, 2019	Sep. 30, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income (loss)	$ (15,260)	[1]	$ 37,141	[1]	$ 25,080	$ 72,361
Depreciation and amortization	$ 15,117		$ 12,545		29,376	25,642
Change in deferred income taxes					16,505	578
Change in operating assets					(46,220)	(19,956)
Change in operating liabilities					15,212	(58,049)
Other					(528)	(66)
Effect of foreign currency fluctuations on cash					$ (252)	$ (8,452)

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