CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 305,076	$ 291,622	$ 110,631
Net Income (Loss) Attributable to Noncontrolling Interest	1,025	707	666
Net Income (Loss) Attributable to Parent	304,051	290,915	109,965
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax	(423)	1,860	963
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax	0	1,792	851
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax	2,538	(4,387)	(7,463)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(172,031)	254,982	(165,931)
Total other comprehensive (loss) income attributable to shareholders	(169,493)	252,387	(172,543)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	134,558	543,302	(62,578)
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax	0	516	402
Accumulated Other Comprehensive Income (Loss)
Net Income (Loss) Attributable to Parent			0
Total other comprehensive (loss) income attributable to shareholders	$ (169,493)	$ 252,387	$ (172,543)