Condensed Consolidated Statement of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Operating revenue:
Oil production	$ 201,758	$ 151,995
Gas production	28,857	41,160
Natural gas liquids production	13,452	5,999
Other operational income	890	885
Total operating revenue	244,957	200,039
Operating expenses:
Lease operating expenses	44,480	38,287
Transportation, processing and gathering expenses	3,657	1,820
Other operational expenses	42	662
Production taxes	3,378	2,535
Depreciation, depletion and amortization	84,575	67,669
Accretion expense	8,266	7,717
Salaries, general and administrative expenses	13,705	11,733
Incentive compensation expense	1,442	2,684
Derivative expense, net	485	2,180
Total operating expenses	160,030	135,287
Income from operations	84,927	64,752
Other (income) expenses:
Interest expense	5,731	3,111
Interest income	(31)	(94)
Other income	(420)	(564)
Other expense		124
Total other expenses	5,280	2,577
Net income before income taxes	79,647	62,175
Provision for income taxes:
Current	1,234
Deferred	27,439	22,383
Total income taxes	28,673	22,383
Net income	$ 50,974	$ 39,792
Basic earnings per share	$ 1.03	$ 0.81
Diluted earnings per share	$ 1.03	$ 0.81
Average shares outstanding	48,254	47,898
Average shares outstanding assuming dilution	48,299	47,939