Accumulated Other Comprehensive Income (Loss) - Classification and Amount of Reclassifications from Accumulated Other Comprehensive Income to Consolidated Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Other non-operating expense (income), net	$ (1,904)	$ 608
Loss before income taxes	(177,549)	(313,905)
Tax effect of net gain (loss)	(6,169)	2,652
Net Loss	(183,718)	(311,253)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) | Derivative Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of sales	927	(4,383)
Tax effect of net gain (loss)	(168)	(48)
Net Loss	759	(4,431)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) | Defined Benefit Pension Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Loss before income taxes	(1,244)	(1,858)
Tax effect of net gain (loss)	(185)	34
Net Loss	(1,429)	(1,824)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) | Amortization of prior service credit
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Other non-operating expense (income), net	493	501
Reclassification Out of Accumulated Other Comprehensive Income (Loss) | Recognized actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Other non-operating expense (income), net	(1,737)	(2,317)
Reclassification Out of Accumulated Other Comprehensive Income (Loss) | Settlement loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income (Loss) [Line Items]
Other non-operating expense (income), net	$ 0	$ (42)