Comprehensive Income (Loss) and Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Pension Plans, Net of Tax
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	$ (14,854)	$ (14,998)	$ (14,998)	$ (15,161)
Other comprehensive income (loss) before reclassifications		0		0
Amounts reclassified out of AOCI	(297)	164	(153)	327
Other comprehensive income (loss)	(297)	164	(153)	327
Balance at the end of the period	(15,151)	(14,834)	(15,151)	(14,834)
Accumulated tax expense (benefit)			2,200	2,000
Foreign Exchange Contracts
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	3,859	(1,232)	2,907	(367)
Other comprehensive income (loss) before reclassifications	(1,325)	(1,981)	(1,432)	(4,599)
Amounts reclassified out of AOCI	(1,104)	1,140	(45)	2,893
Other comprehensive income (loss)	(2,429)	(841)	(1,477)	(1,706)
Balance at the end of the period	1,430	(2,073)	1,430	(2,073)
Ownership Share of Equity Method Investees’ Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	274	(12,123)	(5,299)	(6,739)
Other comprehensive income (loss) before reclassifications	0	(179)	5,573	(5,563)
Other comprehensive income (loss)	0	(179)	5,573	(5,563)
Balance at the end of the period	274	(12,302)	274	(12,302)
Post-Retirement Benefit Plan Adjustments
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	1,087	1,072	1,134	1,114
Amounts reclassified out of AOCI	(47)	(43)	(94)	(85)
Other comprehensive income (loss)	(47)	(43)	(94)	(85)
Balance at the end of the period	1,040	1,029	1,040	1,029
Foreign Currency Translation
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	(21,418)	(16,658)	(25,556)	(10,272)
Other comprehensive income (loss) before reclassifications	9,068	(689)	13,206	(7,075)
Other comprehensive income (loss)	9,068	(689)	13,206	(7,075)
Balance at the end of the period	(12,350)	(17,347)	(12,350)	(17,347)
Net Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss)
Balance at the beginning of the period	(31,052)	(43,939)	(41,812)	(31,425)
Other comprehensive income (loss) before reclassifications	7,743	(2,849)	17,347	(17,237)
Amounts reclassified out of AOCI	(1,448)	1,261	(292)	3,135
Other comprehensive income (loss)	6,295	(1,588)	17,055	(14,102)
Balance at the end of the period	$ (24,757)	$ (45,527)	$ (24,757)	$ (45,527)