Derivatives (Effect Of Derivative Instruments Recognized In Statement of Operations, Not Designated As Hedging Instruments) (Details) (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]
Gain (loss) on derivatives not designated as hedges and hedge ineffectiveness, net	$ 14,627	$ 0	$ 10,052	$ 0
Gain (loss) on derivatives not designated as hedges and hedge ineffectiveness, net [Member] | Commodity Derivatives [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedges and hedge ineffectiveness, net	$ 14,627	$ 0	$ 10,052	$ 0