CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenues:
Oil, natural gas, and natural gas liquids sales	$ 116,786	$ 135,694	$ 234,828	$ 294,595
Interest and other	28	37	160	69
Total revenues	116,814	135,731	234,988	294,664
Costs, expenses, and other:
Lease operating expenses	19,167	27,134	40,371	54,741
Production and property taxes	5,029	6,940	7,245	18,093
Transportation and processing costs	3,098	3,615	6,378	7,587
General and administrative	13,114	16,421	33,128	31,805
Depreciation, depletion, and amortization	43,804	72,987	92,347	139,957
Ceiling test write-down of oil and natural gas properties	0	348,976	0	383,793
Interest expense	29,392	34,317	65,520	67,709
Realized and unrealized gains on derivative instruments, net	(31,610)	(34,015)	(6,030)	(63,539)
Other, net	1,593	3,455	30,413	30,375
Total costs, expenses, and other	83,587	479,830	269,372	670,521
Earnings (loss) before income taxes	33,227	(344,099)	(34,384)	(375,857)
Income tax (benefit) expense	(212)	167,074	125	167,989
Net earnings (loss)	$ 33,439	$ (511,173)	$ (34,509)	$ (543,846)
Basic earnings (loss) per common share (in dollars per share)	$ 0.28	$ (4.44)	$ (0.30)	$ (4.75)
Diluted earnings (loss) per common share (in dollars per share)	$ 0.28	$ (4.44)	$ (0.30)	$ (4.75)