Segment Information (Operating Income And Property And Equipment Costs Incurred) (Details) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Segment Reporting Information [Line Items]
Number of geographical segments	2			2
Revenue	$ 58,987		$ 163,498	$ 227,119	$ 373,316
Depletion, depreciation and accretion	11,650		13,969	39,793	42,584
Impairment of Oil and Gas Properties	164,518		135	241,929	135
Operating income (loss)	(167,047)		64,784	(237,794)	67,266
Property and equipment costs incurred	4,712		28,456	22,545	107,584
Property, plant and equipment, net of accumulated depletion and depreciation	440,820			440,820		$ 728,780
Total assets	668,464			668,464		1,214,302
UNITED STATES
Segment Reporting Information [Line Items]
Revenue	46,964		120,513	173,028	269,310
Depletion, depreciation and accretion	6,133		8,096	19,452	23,652
Impairment of Oil and Gas Properties	150,816		0	150,816	0
Operating income (loss)	(140,889)		57,809	(109,089)	78,891
Property and equipment costs incurred	3,664		20,912	19,615	85,814
Property, plant and equipment, net of accumulated depletion and depreciation	266,992			266,992		416,901
Total assets	547,085			547,085		881,906
CANADA
Segment Reporting Information [Line Items]
Revenue	11,076		42,072	46,631	101,198
Depletion, depreciation and accretion	4,615		4,171	17,495	13,779
Impairment of Oil and Gas Properties	13,702	$ 77,400	0	91,113	0
Operating income (loss)	(18,180)		16,364	(100,723)	20,199
Property and equipment costs incurred	993		7,254	2,557	20,924
Property, plant and equipment, net of accumulated depletion and depreciation	146,960			146,960		280,830
Total assets	87,976			87,976		285,695
Midstream [Member]
Segment Reporting Information [Line Items]
Revenue	3,921		5,184	16,291	16,157
Depletion, depreciation and accretion	543		1,256	1,660	3,744
Impairment of Oil and Gas Properties	0		135	0	135
Operating income (loss)	2,602		2,367	12,516	7,700
Property and equipment costs incurred	0		72	48	83
Property, plant and equipment, net of accumulated depletion and depreciation	23,964			23,964		27,205
Total assets	30,499			30,499		42,857
Corporate [Member]
Segment Reporting Information [Line Items]
Revenue	0		0	0	0
Depletion, depreciation and accretion	359		446	1,186	1,409
Impairment of Oil and Gas Properties	0		0	0	0
Operating income (loss)	(10,580)		(11,756)	(40,498)	(39,524)
Property and equipment costs incurred	55		218	325	763
Property, plant and equipment, net of accumulated depletion and depreciation	2,904			2,904		3,844
Total assets	2,904			2,904		3,844
Elimination [Member]
Segment Reporting Information [Line Items]
Revenue	(2,974)		(4,271)	(8,831)	(13,349)
Depletion, depreciation and accretion	0		0	0	0
Impairment of Oil and Gas Properties	0		0	0	0
Operating income (loss)	0		0	0	0
Property and equipment costs incurred	0		$ 0	0	$ 0
Property, plant and equipment, net of accumulated depletion and depreciation	0			0		0
Total assets	$ 0			$ 0		$ 0