Derivatives (Schedule Of Effect On Operating Results) (Details) (Total Commodity Derivatives [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income, Supply & Logistics Product Costs	$ 5,148	$ 13,569	$ 1,645	$ 2,858
Not Designated As Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Income, Supply & Logistics Product Costs	$ 5,148	$ 13,569	$ 1,645	$ 2,858