Condensed Consolidated Statement of Operations (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Operating revenue:
Oil production	$ 157,436	$ 97,688	$ 484,788	$ 301,412
Gas production	50,244	55,522	152,615	179,571
Other operational income	1,245	1,802	2,994	4,489
Derivative income, net	4,082	405	3,300	3,818
Total operating revenue	213,007	155,417	643,697	489,290
Operating expenses:
Lease operating expenses	47,767	36,882	133,307	112,429
Other operational expenses	654	3,003	1,452	5,450
Production taxes	2,492	1,517	6,828	4,761
Depreciation, depletion and amortization	64,462	60,482	204,777	184,900
Accretion expense	7,700	8,460	23,134	25,384
Salaries, general and administrative expenses	7,151	9,751	29,494	30,199
Incentive compensation expense	2,087	767	7,104	2,113
Total operating expenses	132,313	120,862	406,096	365,236
Income from operations	80,694	34,555	237,601	124,054
Other (income) expenses:
Interest expense	1,379	2,667	6,470	9,273
Interest income	(23)	(51)	(170)	(1,110)
Other income	(372)		(1,499)	(776)
Loss on early extinguishment of debt			607	1,820
Other expense	308	57	501	546
Total other expenses	1,292	2,673	5,909	9,753
Net income before income taxes	79,402	31,882	231,692	114,301
Provision (benefit) for income taxes:
Current	(12,681)	10,182	(15,043)	4,918
Deferred	40,262	2,318	97,926	36,711
Total income taxes	27,581	12,500	82,883	41,629
Net income	$ 51,821	$ 19,382	$ 148,809	$ 72,672
Basic earnings per share	$ 1.06	$ 0.40	$ 3.04	$ 1.50
Diluted earnings per share	$ 1.06	$ 0.40	$ 3.04	$ 1.50
Average shares outstanding	48,029	47,713	47,963	47,659
Average shares outstanding assuming dilution	48,071	47,727	48,006	47,681