Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Net income (loss) (1)	$ 206,587	$ 254,127	$ 47,157
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(24,065)		(15,284)
Other comprehensive income (loss) before reclassifications	(28,959)	41,867
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax	(927)	167	163
Other comprehensive income (loss), net of tax:
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax	(86)	(255)	20
Other Comprehensive Income (Loss) from Equity Method Investments			1,440
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(588)	(1,753)	3,274
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net	(2,249)	0	0
Other comprehensive income (loss) (2)	(27,926)	39,014	(10,387)
Total comprehensive income (1)	178,661	293,141	$ 36,770
Foreign currency translation gains (losses) (2)
Other comprehensive income (loss) before reclassifications	(19,835)	35,271
Defined benefit pension plans
Other comprehensive income (loss) before reclassifications	(1,525)	409
Defined benefit post-retirement plan adjustments
Other comprehensive income (loss) before reclassifications	81	(64)
Equity interest in investee’s other comprehensive income (loss)
Other comprehensive income (loss) before reclassifications	(11)	5,584
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Other comprehensive income (loss) before reclassifications	$ (1,286)	$ 667