Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Net income (loss)	$ 41,381	$ 206,587	$ 254,127
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(5,181)		35,271
Other comprehensive income (loss) before reclassifications (4)(5)	(30,627)	(28,959)
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax	560	(927)	167
Other comprehensive income (loss), net of tax:
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax	(147)	(86)	(255)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(33,519)	(588)	(1,753)
Gain (Loss) from Components Excluded from Assessment of Fair Value Hedge Effectiveness, Net	1,429	(2,249)	0
Other comprehensive income (loss)	(36,858)	(27,926)	39,014
Total comprehensive income	4,523	178,661	293,141
Foreign currency translation gains (losses)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax		(24,065)
Other comprehensive income (loss) before reclassifications (4)(5)	5,097	(19,835)
Defined benefit pension plans
Other comprehensive income (loss) before reclassifications (4)(5)	(302)	(1,525)
Defined benefit post-retirement plan adjustments
Other comprehensive income (loss) before reclassifications (4)(5)	2	81
Equity interest in investee’s other comprehensive income (loss)
Other comprehensive income (loss) before reclassifications (4)(5)	0	(11)	$ 5,584
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Other comprehensive income (loss) before reclassifications (4)(5)	$ (35,078)	$ (1,286)