Derivatives And Risk Management (Before Tax Effect of Basis Swaps that do not Qualify for Hedge Accounting Consolidated Statements of Operations) (Details) (Gas Sales [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Basis Swaps [Member]
Derivative [Line Items]
Derivative Instruments, Unrealized Loss Recognized in Earnings	$ 7,450	$ 766
Derivative Instruments, Realized Gain (Loss) Recognized in Earnings	4,772	2,162
Fixed Price Call Options [Member]
Derivative [Line Items]
Derivative Instruments, Unrealized Loss Recognized in Earnings	(26,259)	(4,128)
Fixed and Floating Price Swaps [Member]
Derivative [Line Items]
Derivative Instruments, Unrealized Loss Recognized in Earnings	37,197
Fair Value Swaps [Member]
Derivative [Line Items]
Derivative Instruments, Unrealized Loss Recognized in Earnings		1,208
Derivative Instruments, Realized Gain (Loss) Recognized in Earnings		(14,958)
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative Instruments, Unrealized Loss Recognized in Earnings	2,992
Derivative Instruments, Realized Gain (Loss) Recognized in Earnings	$ (11)