Basis of Financial Statement Presentation - ASC 606 Adjustment Cash Flow (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018		Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income (loss)	[1],[2]	$ 40,806	$ 18,589	$ 113,167		$ 251,847
Depreciation and amortization		$ 12,763	11,353	38,405	[3]	37,366	[3]
Change in deferred income taxes	[3]			1,395		(3,792)
Change in operating assets	[3]			(42,130)		25,820
Change in operating liabilities	[3]			(61,485)		(26,258)
Other				472		582
Net cash provided by (used in) operating activities	[3]			82,727		82,783
Effect of foreign currency fluctuations on cash	[3]			$ (7,236)		3,017
As Previously Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income (loss)			18,641			252,096
Depreciation and amortization						36,694
Change in deferred income taxes						(3,792)
Change in operating assets						26,296
Change in operating liabilities						(26,316)
Other						499
Net cash provided by (used in) operating activities						82,695
Effect of foreign currency fluctuations on cash						3,105
ASC 606 Adjustments | ASC 606 Adjustments
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income (loss)			$ (52)			(249)
Depreciation and amortization						672
Change in deferred income taxes						0
Change in operating assets						(476)
Change in operating liabilities						58
Other						83
Net cash provided by (used in) operating activities						88
Effect of foreign currency fluctuations on cash						$ (88)

[1] Three and nine months ended December 31, 2017 adjusted due to the adoption of ASC 606.

[2] Three and nine months ended December 31, 2017 adjusted due to the adoption of ASC 606.

[3] Nine months ended December 31, 2017 adjusted due to the adoption of ASC 606.