Derivatives And Risk Management (Before Tax Effect of all Cash Flow Hedges on the Condensed Consolidated Financial Statements) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Fixed Price Swaps [Member]
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income, Effective Portion	$ 37,931	$ 178,660
Costless Collar [Member]
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income, Effective Portion		39,247
Gas Sales [Member] | Fixed Price Swaps [Member]
Derivative [Line Items]
Derivative Instruments, Gain Reclassified from Accumulated Other Comprehensive Income into Earnings, Effective Portion	309,177	413,410
Derivative Instruments, Gain (Loss) Recognized in Earnings, Ineffective Portion	(1,652)	2,450
Gas Sales [Member] | Costless Collar [Member]
Derivative [Line Items]
Derivative Instruments, Gain Reclassified from Accumulated Other Comprehensive Income into Earnings, Effective Portion		218,119
Derivative Instruments, Gain (Loss) Recognized in Earnings, Ineffective Portion		$ (24)