Financial Instruments - Balance Sheet Location (Details) - Fair Value, Measurements, Recurring [Member] - Fair Value, Inputs, Level 2 [Member] - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets [Abstract]
Foreign currency cash flow hedges - asset	$ 1,148	$ 1,874
Liabilities [Abstract]
Foreign currency cash flow hedges - liability	$ 1,741	$ 1,165