Supplemental Financial Information (Parent - Statement of Operations) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues:
Natural gas sales									$ 696,730	$ 969,850	$ 824,266
Oil sales									142,381	260,170	109,138
Total operating revenues	$ 189,301	$ 222,503	$ 207,998	$ 219,309	$ 319,050	$ 288,608	$ 296,063	$ 326,299	839,111	1,230,020	933,404
Expenses:
Lease operating expenses									106,906	96,496	68,106
Liquids gathering system operating lease expense									20,647	20,306	20,000
Production taxes									72,774	103,898	72,398
Gathering fees									87,904	59,931	52,074
Transportation charges									83,803	77,780	82,797
Depletion and depreciation									401,200	292,951	243,390
Ceiling test and other impairments	3,144,899	0	0	0					3,144,899	0	0
General and Administrative Expense									7,387	19,069	22,373
Total operating expenses									3,925,520	670,431	561,138
Operating income (loss)									(3,086,409)	559,589	372,266
Other income (expense), net:
Interest expense	(43,494)	(43,137)	(42,619)	(42,668)	(42,196)	(29,599)	(27,294)	(27,068)	(171,918)	(126,157)	(101,486)
Gain (loss) on commodity derivatives	2	9,390	(3,646)	36,865	110,725	32,052	(15,102)	(45,273)	42,611	82,402	(46,754)
Deferred gain on sale of liquids gathering system									10,553	10,553	10,553
Litigation expense									(4,401)	0	0
Gain on sale of property					8,022	0	0	0	0	8,022	0
Other income (expense) net									(2,060)	2,618	(357)
Total other income (expense), net									(125,215)	(22,562)	(138,044)
Income (loss) before income tax (benefit)	(3,205,639)	(4,229)	(24,923)	23,167	205,829	123,974	105,505	101,719	(3,211,624)	537,027	234,222
Income tax (benefit)	(999)	(1,133)	(250)	(2,022)	(3,901)	(1,383)	(544)	4	(4,404)	(5,824)	(3,616)
Net income (loss)	$ (3,204,640)	$ (3,096)	$ (24,673)	$ 25,189	$ 209,730	$ 125,357	$ 106,049	$ 101,715	$ (3,207,220)	$ 542,851	$ 237,838
Basic Earnings (Loss) per Share:
Earnings Per Share, Basic	$ (20.91)	$ (0.02)	$ (0.16)	$ 0.16	$ 1.37	$ 0.82	$ 0.69	$ 0.66	$ (20.94)	$ 3.54	$ 1.55
Fully Diluted Earnings (Loss) per Share:
Earnings Per Share, Diluted	$ (20.91)	$ (0.02)	$ (0.16)	$ 0.16	$ 1.36	$ 0.81	$ 0.68	$ 0.66	$ (20.94)	$ 3.51	$ 1.54
Weighted average common shares outstanding - basic									153,192,000	153,136,000	152,963,000
Weighted average common shares outstanding - fully diluted									153,192,000	154,694,000	154,426,000
Parent [Member]
Expenses:
General and Administrative Expense									$ 308	$ 261	$ 102
Other income (expense), net:
Interest expense									(81,069)	(42,996)	(1,438)
Income from unconsolidated affiliates									(3,152,078)	558,634	223,685
Guarantee fee income									23,029	23,045	22,406
Other income (expense) net									(1,684)	(1,324)	(1,836)
Income (loss) before income tax (benefit)									(3,212,110)	537,098	242,715
Income tax (benefit)									(4,890)	(5,753)	4,877
Net income (loss)									$ (3,207,220)	$ 542,851	$ 237,838