Derivatives - Foreign Currency Exchange Contracts (Details) - Not Designated as Hedging Instrument	6 Months Ended	12 Months Ended
Jun. 30, 2018 USD ($) ¥ / $ $ / R$ $ / €	Dec. 31, 2017 USD ($) ¥ / $ $ / R$ $ / €
USD/Euro Foreign Exchange Forward, July 27, 2018 \| USD
Derivative [Line Items]
Notional value	$ 15,000,000
Forward rate \| $ / €	1.1575
Unrealized gain/(loss) recorded at balance sheet date	$ (148,000)
USD/Chinese Yuan Renminbi Foreign Exchange Forward, July 27, 2018 \| Chinese Yuan Renminbi
Derivative [Line Items]
Notional value	$ 5,000,000
Forward rate \| ¥ / $	6.6195
Unrealized gain/(loss) recorded at balance sheet date	$ (15,000)
USD/Brazilian Real Foreign Exchange Forward, July 24, 2018 \| USD
Derivative [Line Items]
Notional value	$ 1,000,000
Forward rate \| $ / R$	3.8626
Unrealized gain/(loss) recorded at balance sheet date	$ 6,000
USD/Euro Foreign Exchange Forward, January 5, 2018 \| USD
Derivative [Line Items]
Notional value		$ 17,000,000
Forward rate \| $ / €		1.1858
Unrealized gain/(loss) recorded at balance sheet date		$ (220,000)
USD/Chinese Yuan Renminbi Foreign Exchange Forward, January 5, 2018 \| Chinese Yuan Renminbi
Derivative [Line Items]
Notional value		$ 20,000,000
Forward rate \| ¥ / $		6.6481
Unrealized gain/(loss) recorded at balance sheet date		$ (410,000)
USD/Brazilian Real Foreign Exchange Forward, January 24, 2018 \| USD
Derivative [Line Items]
Notional value		$ 2,500,000.0
Forward rate \| $ / R$		3.2350
Unrealized gain/(loss) recorded at balance sheet date		$ 65,000

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

Contractual rate at which a foreign currency can be purchased or sold.

+ References

No definition available.

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959

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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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