Hedging - Offsetting Derivatives (Details) - Foreign currency forward contracts - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Offsetting Derivative Assets [Abstract]
Gross Amounts Recognized		$ 13
Offsetting Derivative Liabilities [Abstract]
Gross Amounts Recognized		(14,508)
Cash flow hedging \| Designated as hedging instrument
Offsetting Derivative Assets [Abstract]
Gross Amounts Recognized	$ 571	13
Gross Amounts Offset	0	0
Gross Amounts Presented	571	13
Gross Amounts Not Offset	(571)	(13)
Legal Offset	0	0
Offsetting Derivative Liabilities [Abstract]
Gross Amounts Recognized	(16,220)	(14,508)
Gross Amounts Offset	0	0
Gross Amounts Presented	(16,220)	(14,508)
Gross Amounts Not Offset	571	13
Legal Offset	$ (15,649)	$ (14,495)

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