Financial Instruments - Effect of Derivative Instruments on the Consolidated Statements of Operations and the Consolidated Statements of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Other Comprehensive Income (OCI) on Derivative—Effective Portion	$ 3,449	$ 2,608	$ 745
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income—Effective Portion	(1,738)	48	(410)
Amount of Gain (Loss) Recognized in Income on Derivative—Ineffective Portion and Amount Excluded from Effectiveness Testing	0	420	4,042
Foreign currency exchange forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Other Comprehensive Income (OCI) on Derivative—Effective Portion	1,935	3,547	2,294
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income—Effective Portion	(1,520)
Amount of Gain (Loss) Recognized in Income on Derivative—Ineffective Portion and Amount Excluded from Effectiveness Testing	0	0	0
Foreign currency exchange forward contracts | Product revenues / Cost of services and products sold
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income—Effective Portion	(374)	(954)	(410)
Derivative Not Designated as Hedging Instruments
Amount of Gain (Loss) Recognized in Income on Derivative for the Twelve Months Ended December 31	17,262	(23,572)	15,875
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Other Comprehensive Income (OCI) on Derivative—Effective Portion	1,451	(734)
Interest rate swaps | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income—Effective Portion	(1,108)
Cross-currency interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Other Comprehensive Income (OCI) on Derivative—Effective Portion	63	(205)	(1,549)
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income—Effective Portion			0
Cross-currency interest rate swaps | Product revenues / Cost of services and products sold
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income on Derivative—Ineffective Portion and Amount Excluded from Effectiveness Testing	0	420	$ 4,042
Cross-currency interest rate swaps | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income—Effective Portion	$ 1,264	$ 1,002