Derivatives and Hedging Activities (Schedule of Balance Sheet Classification and Fair Values of Derivative Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Notional amount of derivative asset	$ 83,500
Fair value	(978)	$ (568)
Notional amount	99,719	100,873
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member] \| Other current assets [Member]
Derivatives, Fair Value [Line Items]
Fair value derivative asset	121	90
Notional amount of derivative asset	35,453	22,036
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member] \| Accrued expenses and other current liabilities [Member]
Derivatives, Fair Value [Line Items]
Fair value derivative liability	(1,103)	(921)
Notional amount of derivative liability	48,018	65,668
Foreign Exchange Contract [Member] \| Designated as Hedging Instrument [Member] \| Other current assets [Member] \| Cash Flow Hedge [Member]
Derivatives, Fair Value [Line Items]
Fair value derivative asset	24	263
Notional amount of derivative asset	7,788	13,169
Foreign Exchange Contract [Member] \| Designated as Hedging Instrument [Member] \| Accrued expenses and other current liabilities [Member] \| Cash Flow Hedge [Member]
Derivatives, Fair Value [Line Items]
Fair value derivative liability	(20)
Notional amount of derivative liability	$ 8,460

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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Nominal or face amount used to calculate payments on the derivative asset.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
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Nominal or face amount used to calculate payments on the derivative liability.

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