Derivatives Balance Sheet Location (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative assets	$ 1,166	$ 1,020
Other Current Assets | Foreign currency forward contracts | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	1,117	792
Other Current Assets | Foreign currency forward contracts | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	49	228
Accrued Expenses
Derivatives, Fair Value [Line Items]
Derivative liabilities	1,105	219
Accrued Expenses | Foreign currency forward contracts | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	1,044	210
Accrued Expenses | Foreign currency forward contracts | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 61	$ 9