Derivatives (Effect Of Derivative Instruments Recognized In Statement of Operations, Not Designated As Hedging Instruments) (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivatives not designated as hedges and hedge ineffectiveness, net	$ (13,760,000)		$ (4,015,000)		$ (3,340,000)		$ (4,621,000)
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	(13,508,000)	[1]	0	[1]	(3,456,000)	[2]	0	[2]
Loss on derivatives not designated as hedging instruments, amount settled during period	$ (2,434,000)		$ 0		$ (1,575,000)		$ 0

[1] Amount settled during the period is a loss of ($2.434) and $0, respectively.

[2] Amount settled during the period is a loss of ($1.575) and $0, respectively.