Consolidated Statements of Operations (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Operating revenues
Oil and gas sales	$ 64,300	$ 31,105	$ 119,559	$ 73,622
Other revenues	226	249	447	528
Total operating revenues	64,526	31,354	120,006	74,150
Operating costs and expenses
Lease operating	6,201	5,803	11,546	11,331
Production taxes	3,182	1,166	5,634	2,759
Exploration	479	107	605	181
Depletion, depreciation and amortization	26,922	18,249	52,023	37,022
Impairment of oil and gas properties		43		61
Accretion of discount	166	134	263	281
General and administrative	7,325	4,000	11,637	7,675
Total operating expenses	44,275	29,502	81,708	59,310
Operating income	20,251	1,852	38,298	14,840
Other income (expense)
Interest expense	(7,854)	(5,552)	(15,833)	(12,152)
Net gain on commodity derivatives	36,555	30,822	25,172	38,559
Gain (loss) on sales of assets	(45)	(72)	25	1,356
Other income (expense), net	28,656	25,198	9,364	27,763
Income before income tax	48,907	27,050	47,662	42,603
Income tax provision
Current	12		34
Deferred	240	112	217	223
Total income tax provision	252	112	251	223
Net income	$ 48,655	$ 26,938	$ 47,411	$ 42,380