CONDENSED CONSOLIDATED STATEMENT OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Operating revenue:
Oil production	$ 180,806	$ 157,436	$ 564,745	$ 484,788
Gas production	34,003	42,771	91,006	131,815
Natural gas liquids production	11,910	9,060	35,228	25,290
Other operational income	678	1,245	2,520	2,994
Derivative income, net	(1,812)	4,082	3,119	3,300
Total operating revenue	227,397	214,594	696,618	648,187
Operating expenses:
Lease operating expenses	60,995	46,591	157,030	130,486
Transportation, processing and gathering expenses	6,762	2,763	15,911	7,311
Other operational expenses	82	654	195	1,452
Production taxes	1,842	2,492	7,578	6,828
Depreciation, depletion and amortization	89,274	64,462	260,982	204,777
Accretion expense	8,405	7,700	24,926	23,134
Salaries, general and administrative expenses	13,673	7,151	40,521	29,494
Incentive compensation expense	67	2,087	3,907	7,104
Derivative expense, net	1,812
Total operating expenses	182,912	133,900	511,050	410,586
Income from operations	44,485	80,694	185,568	237,601
Other (income) expenses:
Interest expense	7,692	1,379	21,107	6,470
Interest income	(117)	(23)	(227)	(170)
Other income	(443)	(372)	(1,229)	(1,499)
Loss on early extinguishment of debt				607
Other expense		308		501
Total other (income) expenses	7,132	1,292	19,651	5,909
Income (loss) before taxes	37,353	79,402	165,917	231,692
Provision (benefit) for income taxes:
Current	595	(12,681)	1,164	(15,043)
Deferred	13,099	40,262	59,573	97,926
Total income taxes	13,694	27,581	60,737	82,883
Net income	$ 23,659	$ 51,821	$ 105,180	$ 148,809
Basic earnings per share	$ 0.48	$ 1.06	$ 2.13	$ 3.04
Diluted earnings per share	$ 0.48	$ 1.06	$ 2.13	$ 3.04
Average shares outstanding	48,342	48,029	48,300	47,963
Average shares outstanding assuming dilution	48,384	48,071	48,343	48,006