Consolidated Statements Of Operations (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revenues:
Oil and natural gas sales	$ 127,512	$ 127,789
Gain from oil hedging activities	10,003	12,423
Total revenues	137,515	140,212
Costs and expenses:
Lease operating	33,977	30,949
Production taxes	7,880	8,290
Depreciation, depletion and amortization	43,916	36,932
General and administrative	14,008	13,449
Total costs and expenses	99,781	89,620
Operating income	37,734	50,592
Non-operating expense:
Interest expense	(24,291)	(24,156)
Non-hedge derivative losses	(15,546)	(10,463)
Other income, net	226	5
Net non-operating expense	(39,611)	(34,614)
(Loss) income before income taxes	(1,877)	15,978
Income tax (benefit) expense	(687)	6,196
Net (loss) income	$ (1,190)	$ 9,782