Derivative Instruments and Hedging Activities (Gain Loss Recognized In Income On Hedged Derivatives) (Details) - Derivatives Not Designated As Hedging Instruments Under ASC Topic 815 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in Income on Derivative	$ 503	$ 167	$ (648)
Commodities contracts | Cost of Sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) Recognized in Income on Derivative	$ 503	$ 167	$ (648)