Selected Quarterly Financial Data (Unaudited) (Details) (USD $)	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 Information Disclosure [Abstract]
Total oil, natural gas liquids, and natural gas sales	$ 106,962,000	$ 122,125,000	$ 120,970,000	$ 112,306,000	$ 109,337,000	$ 96,007,000	$ 81,356,000	$ 67,523,000	$ 462,363,000	$ 354,223,000	$ 177,422,000
Costs and expenses associated directly with products sold	87,746,000	83,016,000	78,280,000	60,059,000	65,563,000	57,578,000	49,825,000	44,207,000
Net income (loss) before income taxes	(322,711,000)	42,544,000	(9,880,000)	(1,686,000)	1,315,000	6,546,000	28,291,000	(25,575,000)	(291,733,000)	10,577,000	(686,799,000)
Net income (loss)	(357,698,000)	42,544,000	(9,880,000)	(1,686,000)	1,315,000	6,546,000	28,291,000	(25,575,000)	(326,720,000)	10,577,000	(686,799,000)
Basic and diluted net income (loss) per share	$ (2.70)	$ 0.36	$ (0.08)	$ (0.01)	$ 0.01	$ 0.06	$ 0.24	$ (0.22)
Goodwill impairment	$ 173,500,000								$ 173,500,000	$ 0