Derivatives (Schedule Of Effect On Operating Results) (Details) - Total Commodity Derivatives [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income, Supply & Logistics Product Costs	$ (890)	$ 1,381
Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income, Supply & Logistics Product Costs	(553)	2,186
Not Designated As Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income, Supply & Logistics Product Costs	$ (337)	$ (805)