Hedging - Derivative Fair Value (Details) - Foreign currency forward contracts - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Total assets	$ 20,537	$ 13
Total liabilities	(448)	(14,508)
Designated as hedging instruments
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Total assets	20,537	13
Total liabilities	(448)	(14,508)
Prepaid and other current assets \| Designated as hedging instruments
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Fair value - assets	19,023	13
Other liabilities, current portion \| Designated as hedging instruments
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Fair value - liabilities	(340)	(13,642)
Other assets \| Designated as hedging instruments
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Fair value - assets	1,514	0
Other liabilities, excluding current portion \| Designated as hedging instruments
Foreign Currency Cash Flow Hedge Derivative at Fair Value [Abstract]
Fair value - liabilities	$ (108)	$ (866)

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value as of the balance sheet date of all foreign currency derivative assets designated as cash flow hedging instruments.

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Fair value as of the balance sheet date of all foreign currency derivative liabilities designated as cash flow hedging instruments.

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