Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 30, 2019		Sep. 30, 2018		Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (15,260)	[1]	$ 37,141	[1]	$ 25,080	$ 72,361
Other comprehensive income (loss), net of tax:
Foreign currency translation gains (losses)	(7,966)		(3,149)		(4,787)	(27,352)
Defined benefit pension plans	162		248		326	287
Defined benefit post-retirement plan adjustments	(37)		(39)		(74)	(78)
Equity interest in investee's other comprehensive income (loss)	0		(6)		0	(17)
Cash flow hedges	(4,153)		5,188		(10,151)	750
Excluded component of fair value hedges	45		0		1,337	0
Other comprehensive income (loss)	(11,949)		2,242		(13,349)	(26,410)
Total comprehensive income (loss)	$ (27,209)		$ 39,383		$ 11,731	$ 45,951

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