Unaudited Condensed Consolidated Statements of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues
Crude oil and natural gas sales	$ 988,956	$ 617,934	$ 2,616,126	$ 1,664,438
Crude oil and natural gas sales to affiliates	29,828	15,410	78,362	44,557
Gain (loss) on derivative instruments, net	(203,774)	(158,294)	(89,548)	144,377
Crude oil and natural gas service operations	8,825	8,679	29,876	30,176
Total revenues	823,835	483,729	2,634,816	1,883,548
Operating costs and expenses
Production expenses	66,790	53,952	201,250	137,447
Production and other expenses to affiliates	1,422	1,454	4,574	3,950
Production taxes and other expenses	92,120	61,717	244,428	159,524
Exploration expenses	8,173	4,899	29,138	17,752
Crude oil and natural gas service operations	6,654	7,626	22,567	24,723
Depreciation, depletion, amortization and accretion	244,721	189,374	695,189	499,847
Property impairments	42,167	27,375	161,960	93,153
General and administrative expenses	34,070	31,925	103,761	86,704
Gain on sale of assets, net	(325)	(115)	(112)	(67,139)
Total operating costs and expenses	495,792	378,207	1,462,755	955,961
Income from operations	328,043	105,522	1,172,061	927,587
Other income (expense):
Interest expense	(62,756)	(39,205)	(171,609)	(95,174)
Other	584	710	1,765	2,280
Total other income (expense)	(62,172)	(38,495)	(169,844)	(92,894)
Income before income taxes	265,871	67,027	1,002,217	834,693
Provision for income taxes	98,373	22,931	370,822	315,819
Net income	$ 167,498	$ 44,096	$ 631,395	$ 518,874
Basic net income per share (in dollars per share)	$ 0.91	$ 0.24	$ 3.43	$ 2.88
Diluted net income per share (in dollars per share)	$ 0.91	$ 0.24	$ 3.42	$ 2.86