Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Net income (loss)	$ 52,914	$ 12,278	$ (4,998)	$ (12,205)	$ (15,173)	$ (8,600)	$ 7,194	$ (37,050)	$ 47,989	$ (53,629)	$ (14,143)
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax									(5,708)	213
Other comprehensive income (loss)									(10,387)	(2,629)	(46,980)
Total comprehensive income (loss)									37,602	(56,258)	(61,123)
Foreign currency translation gains (losses), net of tax
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax									(15,284)	1,860	(35,467)
Other comprehensive income (loss)									(15,284)	1,860
Defined benefit pension plans, net of tax
Other comprehensive income (loss):
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 (loss)									(163)	5,202
Defined benefit post-retirement plan adjustments
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax									228	146
Amounts reclassified out of OCI									20	(45)	(305)
Other comprehensive income (loss)									(20)	(45)
Equity interest in investee’s other comprehensive income (loss)
Other comprehensive income (loss):
Amounts reclassified out of OCI									1,440	(8,276)	766
Other comprehensive income (loss)									1,440	(8,276)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax									(8,444)	(2,618)
Other comprehensive income (loss)									$ 3,274	$ (1,370)	$ 1,003