Supplemental Oil and Natural Gas Disclosures (Unaudited) (Details 2)	12 Months Ended
	Dec. 31, 2012 MBoe	Dec. 31, 2011 MBoe	Dec. 31, 2010 MBoe	Dec. 31, 2009 MBoe
Summary of Estimated reserves
Total	32,196	21,387	10,758
Revisions of prior estimates	(18,010)	(57)	211
Extensions and discoveries	12,927	13,439	11,851
Production	(3,294)	(2,573)	(1,433)
Total	23,819	32,196	21,387
Proved Developed Reserves	13,771	10,843	7,342	4,331
Proved oil and natural gas reserves	10,048	21,353	14,045	6,427
Oil [Member]
Summary of Estimated reserves
Total	3,794	152	103
Revisions of prior estimates	(782)	51	66
Extensions and discoveries	8,687	3,745	16
Production	(1,214)	(154)	(33)
Total	10,485	3,794	152
Proved Developed Reserves	4,764	1,419	152	103
Proved oil and natural gas reserves	5,721	2,375
Natural Gas [Member]
Summary of Estimated reserves
Total	170,418	127,412	63,929
Revisions of prior estimates	(103,375)	(646)	874
Extensions and discoveries	25,443	58,164	71,009
Production	(12,479)	(14,512)	(8,400)
Total	80,007	170,418	127,412
Proved Developed Reserves	54,040	56,547	43,143	25,369
Proved oil and natural gas reserves	25,967	113,871	84,269	38,560