Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Net income (loss)	$ (15,173)	$ (8,600)	$ 7,194	$ (37,050)	$ (19,847)	$ 2,914	$ 6,330	$ (3,540)	$ (53,629)	$ (14,143)	$ (68,503)
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax									213	(47,221)
Other comprehensive income (loss)									(2,629)	(46,980)	10,490
Total comprehensive income (loss)									(56,258)	(61,123)	(58,013)
Foreign currency translation gains (losses), net of tax
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax									1,860	(35,467)	9,797
Other comprehensive income (loss)									1,860	(35,467)
Accumulated Defined Benefit Plans Adjustment [Member]
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax									3,865	(13,404)
Amounts reclassified out of OCI									5,202	12,977	276
Other comprehensive income (loss)									(5,202)	(12,977)
Defined benefit post-retirement plan adjustments
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax									146	(119)
Amounts reclassified out of OCI									(45)	305	(354)
Other comprehensive income (loss)									45	(305)
Equity interest in investee's other comprehensive income (loss)
Other comprehensive income (loss):
Amounts reclassified out of OCI									(8,276)	(766)	771
Other comprehensive income (loss)									(8,276)	766
Forward Contracts
Other comprehensive income (loss):
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax									(2,618)	(1,003)
Other comprehensive income (loss)									$ (1,370)	$ 1,003	$ 0