Income Taxes - Deferred Taxes (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Deferred tax assets:
Reserves and accruals	$ (8,320)	$ (24,308)
Tax credits	(5,146)	(7,286)
Tax loss carryforwards	(101,884)	(125,601)
Derivative transactions	(1,038)	(669)
Postretirement and other benefits	(15,766)	(28,512)
Unrealized exchange loss	(4,923)	(4,046)
Other	(3,895)	(8,471)
Gross deferred tax assets	(140,972)	(198,893)
Valuation allowance	19,742	131,774
Total deferred tax assets	(121,230)	(67,119)
Deferred tax liabilities:
Unremitted earnings of foreign subsidiaries	5,854	30,581
Intangible assets	5,801	8,397
Fixed assets	7,992	7,242
Total deferred tax liabilities	19,647	46,220
Net deferred tax asset	$ (101,583)	$ (20,899)