Property, Plant And Equipment (Narrative) (Details) (USD $)	3 Months Ended				12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Percentage drop in Henry Hub price						33.00%
Percentage decrease related to NGL prices						28.00%
Percentage decrease of AECO stated price						36.00%	12.00%
Impairment expense					$ 1,863,000	$ 2,625,928,000	$ 107,059,000
Capitalized overhead costs related to exploration and development activities					13,600,000	16,800,000	18,300,000
Depletion per Mcfe							1.35
Depreciation Expense					17,100,000	18,600,000	20,300,000
Midstream Assets Texas [Member]
Property, Plant and Equipment [Line Items]
Additional impairment charges							58,000,000
Horn River Asset [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated years for evaluation of acquisition costs					9 years
U.S. [Member]
Property, Plant and Equipment [Line Items]
Impairment expense	451,500,000	479,900,000	1,042,700,000	178,000,000	1,809,000	2,152,665,000	0
Depletion per Mcfe					0.51	1.14
West Texas [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated years for evaluation of acquisition costs					3 years
Canada [Member]
Property, Plant and Equipment [Line Items]
Impairment expense	102,800,000	66,300,000	157,000,000	139,900,000	0	465,935,000	49,063,000
Depletion per Mcfe					$ 0.14	$ 0.83