Derivatives - Amount of Gain (Loss) Recognized in OCI and Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) recognized in OCI	$ (1,154)	$ 881	$ (3,731)	$ 2,873
Derivatives designated as cash flow hedges \| Interest rate swap
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) recognized in OCI	(1,812)	748	(2,669)	2,868
Derivatives designated as cash flow hedges \| Interest rate swap \| Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) recognized in income	(3,115)	(3,338)	(5,879)	(5,736)
Amount of Gain/(Loss) reclassified from AOCI	602		1,196
Amount of Gain/(Loss) reclassified from AOCI		357		570
Derivatives designated as cash flow hedges \| Foreign currency forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) recognized in OCI	1,064	394	51	568
Derivatives designated as cash flow hedges \| Foreign currency forward contracts \| Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) recognized in income	255,532	224,810	493,881	427,844
Amount of Gain/(Loss) reclassified from AOCI	(92)		102
Amount of Gain/(Loss) reclassified from AOCI		(234)		(385)
Derivatives designated as cash flow hedges \| Foreign currency forward contracts \| Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) recognized in income	(143,568)	(124,801)	(277,281)	(239,779)
Amount of Gain/(Loss) reclassified from AOCI	$ (104)		$ (185)
Amount of Gain/(Loss) reclassified from AOCI		$ 138		$ 378

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Amount, before tax and after reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness, attributable to parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
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Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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