Quarterly Financial Data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Data [Abstract]
Revenues	$ 90,567	$ 86,445	$ 44,857	$ 94,163	$ 116,926	$ 36,901	$ 126,165	$ 57,672	$ 316,032	$ 337,664	$ 219,058
Operating expenses	542,897	338,512	44,338	76,987	87,922	44,899	94,908	49,453	86,990	105,444	58,536
Operating profit (loss)	(452,330)	(252,067)	519	17,176	29,004	(7,998)	31,257	8,219	(686,702)	60,482	19,801
Net income (loss) to common shareholders	(464,477)	(294,652)	(37,129)	(45,326)	(28,118)	(40,341)	(14,341)	(14,502)	(841,584)	(97,302)	(128,049)
Net income (loss) per common share - basic and diluted	$ (9.34)	$ (5.64)	$ (0.72)	$ (0.91)	$ (0.60)	$ (0.86)	$ (0.30)	$ (0.31)	$ (16.61)	$ (2.07)	$ (3.01)
Litigation settlement expense									19,034
Loss on early extinguishment of financing agreements		30,700		3,500					(34,297)		(21,661)
Goodwill impairment loss									259,238
Impairment of oil and gas properties						6,000		3,500	476,721	9,566	53,072
Restructuring charges	43,200								43,222
Impairment of oil and gas properties						$ 6,000		$ 3,500	$ 476,721	$ 9,566	$ 53,072