Basis of Financial Statement Presentation - ASC 606 Adjustment Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income (loss)	$ 35,220	$ 220,439
Foreign currency translation gains (losses)	(24,203)	4,353
Other comprehensive income (loss)	(28,652)	10,975
Total comprehensive income (loss) (1)	$ 6,568	231,414
As Previously Reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income (loss)		220,606
Foreign currency translation gains (losses)		4,138
Other comprehensive income (loss)		10,760
Total comprehensive income (loss) (1)		231,366
Adjustments | Adjustments
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net income (loss)		(167)
Foreign currency translation gains (losses)		215
Other comprehensive income (loss)		215
Total comprehensive income (loss) (1)		$ 48