Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues
Oil and natural gas revenues	$ 269,030	$ 155,998	$ 67,000
Realized (loss) gain on derivatives	(909)	13,960	7,106
Unrealized (loss) gain on derivatives	(7,232)	(4,802)	5,138
Total revenues	260,889	165,156	79,244
Expenses
Production taxes and marketing	20,973	11,672	6,278
Lease operating	38,720	28,184	7,244
Depletion, depreciation and amortization	98,395	80,454	31,754
Accretion of asset retirement obligations	348	256	209
Full-cost ceiling impairment	21,229	63,475	35,673
General and administrative	20,779	14,543	13,394
Total expenses	200,444	198,584	94,552
Operating income (loss)	60,445	(33,428)	(15,308)
Other income (expense)
Net loss on asset sales and inventory impairment	(192)	(485)	(154)
Interest expense	(5,687)	(1,002)	(683)
Interest and other income	225	224	315
Total other expense	(5,654)	(1,263)	(522)
Income (loss) before income taxes	54,791	(34,691)	(15,830)
Income tax provision (benefit)
Current	404	0	(46)
Deferred	9,293	(1,430)	(5,475)
Total income tax provision (benefit)	9,697	(1,430)	(5,521)
Net income (loss)	$ 45,094	$ (33,261)	$ (10,309)
Basic
Basic	58,777	53,957	42,718
Diluted
Diluted	58,929	53,957	42,718
Class A
Basic
Basic (usd per share)	$ 0.77	$ (0.62)	$ (0.25)
Diluted
Diluted (usd per share)	$ 0.77	$ (0.62)	$ (0.25)
Basic
Basic	58,777	53,852	41,687
Diluted
Diluted	58,929	53,852	41,687
Class B
Basic
Basic (usd per share)	$ 0.00	$ (0.35)	$ 0.02
Diluted
Diluted (usd per share)	$ 0.00	$ (0.35)	$ 0.02
Basic
Basic	0	105	1,031
Diluted
Diluted	0	105	1,031