Condensed Consolidated Statements 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
Revenue:
Oil and natural gas	$ 86,645	$ 84,853	$ 284,666	$ 244,866
Other	23	31	68	97
Total Revenues	86,668	84,884	284,734	244,963
Costs and expenses:
Lease operating	24,995	19,266	62,067	52,505
Transportation	160	119	410	490
Exploration expenditures and dry hole costs	966	973	17,862	2,343
Impairments	498	5,523	6,206	19,197
Depreciation, depletion and amortization	27,106	26,496	78,932	73,081
Accretion of liability for asset retirement obligations	3,472	4,793	10,031	12,172
General and administrative	5,995	4,461	16,993	14,544
Taxes, other than on earnings	3,189	3,493	9,834	10,506
Other	998	4,108	4,616	6,140
Total costs and expenses	67,379	69,232	206,951	190,978
Income from operations	19,289	15,652	77,783	53,985
Other income (expense):
Interest income	40	37	128	64
Interest expense	(5,114)	(5,036)	(15,081)	(12,480)
Gain (loss) on derivative instruments	(22,108)	26,571	(11,865)	14,877
Loss on early extinguishment of debt				(2,377)
Total other income (expense)	(27,182)	21,572	(26,818)	84
Income (loss) before income taxes	(7,893)	37,224	50,965	54,069
Provision for income taxes:
Current	126		(174)
Deferred	5,520	(13,766)	(16,134)	(20,117)
Total provision for income taxes	5,646	(13,766)	(16,308)	(20,117)
Net income (loss)	$ (2,247)	$ 23,458	$ 34,657	$ 33,952
Basic earnings (loss) per share	$ (0.06)	$ 0.58	$ 0.88	$ 0.84
Diluted earnings (loss) per share	$ (0.06)	$ 0.58	$ 0.88	$ 0.84
Weighted average common shares used in computing earnings per share:
Basic	38,743	40,093	38,926	40,094
Diluted	38,743	40,153	39,056	40,172