Derivatives (Schedule Of Fair Value Of Derivative Assets And Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 758		$ 306
Liability Derivatives	(3,357)		(2,820)
Other Current Assets [Member] | Commodity Derivatives [Member] | Not Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	758		306
Liability Derivatives	$ (3,357)	[1]	$ (2,820)	[1]

[1] These derivative liabilities have been funded with margin deposits recorded in our Consolidated Balance Sheets under Current Assets - Other.