Derivatives (Effect Of Derivative Instruments Recognized In Statement Of Operations, Not Designated As Hedging Instruments) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Gain on derivatives not designated as hedges		$ 26,345	$ 30,147
Cash receipts (payments) on derivatives settled		46,615	(6,038)
Commodity Contract
Derivative Instruments, Gain (Loss) [Line Items]
Gain on derivatives not designated as hedges	[1]	$ 26,345	$ 30,147

[1] Amount settled during the period is a gain of $46,615 and a loss of $6,038, respectively.