Derivatives (Fair Value of the Company's Other Derivatives) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Not Designated as Hedging Instrument | Other long term liabilities | Interest rate contracts
Derivative [Line Items]
Derivative liabilities	$ (37)	$ (1,244)	$ (2,158)
Not Designated as Hedging Instrument | Short term assets (liabilities) | Foreign currency contract
Derivative [Line Items]
Derivative assets	(1,109)	426	654
Designated as Hedging Instrument | Other Expenses and Other Current Liabilities | Interest rate contracts
Derivative [Line Items]
Derivative liabilities	(88)	0	0
Designated as Hedging Instrument | Other Assets | Interest rate contracts
Derivative [Line Items]
Derivative liabilities	$ 155	$ 0	$ 0