Components of Accumulated Other Comprehensive Loss - Reclassification out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Operating Income (Expense), Net	$ (383)			$ (335)			$ (409)	$ (985)
Discontinued Operation, Gain From Disposal Of Discontinued Operation, Before Income Tax				0				0
Product revenues	423,155			351,563			1,103,955	1,015,910
Interest expense	12,819			5,620			24,429	16,891
Income from continuing operations before income taxes	32,857			37,523			49,749	88,823
Income tax expense (benefit)	12,601			11,054			17,814	16,750
Net income	437,857	$ 10,929	$ 22,537	34,651	$ 42,711	$ 19,577	471,323	96,939
Amount Reclassified from Accumulated Other Comprehensive Loss | Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Operating Income (Expense), Net	(154)
Amount Reclassified from Accumulated Other Comprehensive Loss | Cumulative Unrecognized Actuarial Losses on Pension Obligations
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations before income taxes	4,782			5,002			15,082	15,226
Income tax expense (benefit)	(340)			(289)			(1,061)	(902)
Net income	4,442			4,713			14,021	14,324
Amount Reclassified from Accumulated Other Comprehensive Loss | Effective Portion of Deriviatives Designated as Hedging Instruments
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income from continuing operations before income taxes	(297)			(58)			2,068	246
Income tax expense (benefit)	(21)			(13)			(664)	(220)
Net income	(318)			(71)			1,404	26
Amount Reclassified from Accumulated Other Comprehensive Loss | Effective Portion of Deriviatives Designated as Hedging Instruments | Foreign currency exchange forward contracts
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other Operating Income (Expense), Net				0			(2,425)	0
Discontinued Operation, Gain From Disposal Of Discontinued Operation, Before Income Tax	662			0			662	0
Product revenues	(512)			(3)			(977)	(112)
Cost of services sold	0			0			44	0
Amount Reclassified from Accumulated Other Comprehensive Loss | Effective Portion of Deriviatives Designated as Hedging Instruments | Cross currency interest rate swaps
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	291			312			908	960
Amount Reclassified from Accumulated Other Comprehensive Loss | Effective Portion of Deriviatives Designated as Hedging Instruments | Interest rate swaps
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Interest expense	(76)			(367)			(648)	(602)
Income from discontinued business	0			0			2,741	0
Amount Reclassified from Accumulated Other Comprehensive Loss | Actuarial losses
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Defined benefit pension income (expense)	4,721			5,039			14,761	15,173
Amount Reclassified from Accumulated Other Comprehensive Loss | Prior service costs (benefits)
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Defined benefit pension income (expense)	61			(37)			192	(113)
Amount Reclassified from Accumulated Other Comprehensive Loss | Settlement/curtailment losses
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Defined benefit pension income (expense)	$ 0			$ 0			$ 129	$ 166