Hedging - Derivative Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Foreign currency forward contracts
Derivative [Line Items]
Total assets		$ 13
Total liabilities		(14,508)
Designated as hedging instrument \| Foreign currency forward contracts \| Cash flow hedging
Derivative [Line Items]
Total assets	$ 571	13
Total liabilities	(16,220)	(14,508)
Prepaid and other current assets
Derivative [Line Items]
Fair Value - assets	540	13
Prepaid and other current assets \| Not designated as hedging instrument \| Foreign currency forward contracts
Derivative [Line Items]
Fair Value - assets	115
Total assets		0
Other liabilities, current portion
Derivative [Line Items]
Fair Value - liabilities	(15,370)	(13,642)
Other liabilities, current portion \| Not designated as hedging instrument \| Foreign currency forward contracts
Derivative [Line Items]
Total liabilities	0	(684)
Other assets
Derivative [Line Items]
Fair Value - assets	31	0
Other liabilities, excluding current portion
Derivative [Line Items]
Fair Value - liabilities	$ (850)	$ (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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Section 50
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Fair value as of the balance sheet date of all foreign currency derivative assets designated as cash flow hedging instruments.

+ References

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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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