Hedging - Narrative (Details) - USD ($)	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Derivative [Line Items]
Amount of ineffectiveness on net hedges	$ 0
Cash flow hedging \| Foreign currency forward contracts \| Minimum
Derivative [Line Items]
Derivative term	1 month
Cash flow hedging \| Foreign currency forward contracts \| Maximum
Derivative [Line Items]
Derivative term	18 months
Not designated as hedging instrument \| Foreign currency forward contracts
Derivative [Line Items]
Derivative term	1 month
Notional amount of foreign currency forward contract	$ 88,900,000
Other income (expense) \| Not designated as hedging instrument \| Foreign currency forward contracts
Derivative [Line Items]
(Loss) gain recognized on forward contracts not designated as hedges	$ (1,500,000)	$ (3,500,000)

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Gain (loss) on hedging derivative instrument or the foreign currency transaction gain (loss) on the nonderivative hedging instrument designated as a hedge of a net investment in foreign operations related to hedge ineffectiveness, which is included in earnings in the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

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- Definition

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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