CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
OPERATING REVENUES
Natural gas	$ 433,442	$ 227,578
Crude oil and condensate	42,990	30,676
Gain on derivative instruments	33,384	18,994
Brokered natural gas	4,695	3,180
Other	3,332	1,513
TOTAL OPERATING REVENUES	517,843	281,941
OPERATING EXPENSES
Direct operations	24,641	26,035
Transportation and gathering	123,474	109,652
Brokered natural gas	4,046	2,566
Taxes other than income	9,058	5,994
Exploration	6,198	6,383
Depreciation, depletion and amortization	135,100	161,887
General and administrative	23,700	27,873
TOTAL OPERATING EXPENSES	326,217	340,390
Earnings (loss) on equity method investments	(1,283)	2,009
Gain (loss) on sale of assets	(223)	1,354
INCOME (LOSS) FROM OPERATIONS	190,120	(55,086)
Interest expense	20,771	24,375
Other expense	424	503
Income (loss) before income taxes	168,925	(79,964)
Income tax expense (benefit)	63,205	(28,770)
NET INCOME (LOSS)	$ 105,720	$ (51,194)
Earnings (loss) per share
Basic (in dollars per share)	$ 0.23	$ (0.12)
Diluted (in dollars per share)	$ 0.23	$ (0.12)
Weighted-average common shares outstanding
Basic (in shares)	465,348	431,841
Diluted (in shares)	466,888	431,841
Dividends per common share (in dollars per share)	$ 0.02	$ 0.02