Fair Value of Financial Instruments (Details Textual) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2018 EUR (€)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Purchase amount of forward foreign exchange currency contract | €			€ 370,000
Realized loss on forward foreign exchange contract	$ (958)	$ (2,535)
Derivative expiration, description		expire at various dates through February 2019
Forward Foreign Exchange Contracts [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative instrument, notional amount	$ 10,050	$ 10,050