Organization and Significant Accounting Policies - OCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Accumulated other comprehensive income (loss)
Balance at the beginning of the period	$ (31,425)	$ (28,796)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	5,708	(213)
Other Comprehensive Income, Other, Net of Tax	(4,679)	(2,842)
Other comprehensive income (loss)	10,387	2,629	$ 46,980
Balance at the end of the period	(41,812)	(31,425)	(28,796)
Foreign currency translation gains (losses), net of tax
Accumulated other comprehensive income (loss)
Balance at the beginning of the period	(10,272)	(12,132)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	15,284	(1,860)	35,467
Other Comprehensive Income, Other, Net of Tax	0	0
Other comprehensive income (loss)	15,284	(1,860)
Balance at the end of the period	(25,556)	(10,272)	(12,132)
Defined benefit post-retirement plan adjustments
Accumulated other comprehensive income (loss)
Balance at the beginning of the period	1,114	1,159
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(228)	(146)
Amounts reclassified out of OCI	20	(45)	(305)
Other Comprehensive Income, Other, Net of Tax	208	191
Other comprehensive income (loss)	20	45
Balance at the end of the period	1,134	1,114	1,159
Defined benefit pension plans, net of tax
Accumulated other comprehensive income (loss)
Balance at the beginning of the period	(15,161)	(20,363)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	536	(3,865)
Amounts reclassified out of OCI	163	5,202	(12,977)
Other Comprehensive Income, Other, Net of Tax	(699)	(1,337)
Other comprehensive income (loss)	163	(5,202)
Balance at the end of the period	(14,998)	(15,161)	(20,363)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	0	0
Defined Benefit Pension Plans, tax benefit	700	(300)
Other Comprehensive Income (Loss), Tax	2,700	2,000	2,300
Equity interest in investee's other comprehensive loss
Accumulated other comprehensive income (loss)
Balance at the beginning of the period	(6,739)	1,537
Amounts reclassified out of OCI	1,440	(8,276)	766
Other Comprehensive Income, Other, Net of Tax	0	0
Other comprehensive income (loss)	(1,440)	8,276
Balance at the end of the period	(5,299)	(6,739)	1,537
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Accumulated other comprehensive income (loss)
Balance at the beginning of the period	(367)	1,003
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	8,444	2,618
Other Comprehensive Income, Other, Net of Tax	(5,170)	3,988
Other comprehensive income (loss)	(3,274)	1,370	(1,003)
Balance at the end of the period	$ 2,907	$ (367)	$ 1,003