Derivatives (Schedule Of Fair Value Of Derivative Assets And Liabilities) (Details) (Other Current Assets [Member], Total Commodity Derivatives [Member], Not Designated As Hedging Instrument [Member], USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Other Current Assets [Member] | Total Commodity Derivatives [Member] | Not Designated As Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 688	$ 758
Derivative Liability, Fair Value, Gross Liability	1,265	3,357
GrossAmountDerivativeAssetsOffset	(688)	(758)
NetAmountofDerivativeAssets	0	0
GrossAmountofDerivativeLiabilitiesOffset	1,265	3,357
Net amount of derivative liabilities	$ 0	$ 0