Hedging - Offsetting Derivatives (Details) - Cash flow hedging - Foreign currency forward contracts - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Offsetting Derivative Assets [Abstract]
Gross Amounts Recognized	$ 20,183	$ 20,537
Offsetting Derivative Liabilities [Abstract]
Gross Amounts Recognized	(378)	(448)
Designated as hedging instruments
Offsetting Derivative Assets [Abstract]
Gross Amounts Recognized	20,183	20,537
Gross Amounts Offset	0	0
Gross Amounts Presented	20,183	20,537
Gross Amounts Not Offset	(378)	(448)
Legal Offset	19,805	20,089
Offsetting Derivative Liabilities [Abstract]
Gross Amounts Recognized	(378)	(448)
Gross Amounts Offset	0	0
Gross Amounts Presented	(378)	(448)
Gross Amounts Not Offset	378	448
Legal Offset	$ 0	$ 0

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