Long-Term Debt - Senior Secured Revolving Credit Facility (Details) (USD $) In Thousands, unless otherwise specified				6 Months Ended									6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Aug. 14, 2012 Subsequent Event	Jun. 30, 2012 Line of Credit	Jun. 30, 2012 Line of Credit Election One	Jun. 30, 2012 Line of Credit Election Two	Jun. 30, 2012 Line of Credit Election Three	Jun. 30, 2012 Line of Credit Eurodollar Rate	Jun. 30, 2012 Line of Credit Eurodollar Rate Minimum	Jun. 30, 2012 Line of Credit Eurodollar Rate Maximum	Jun. 30, 2012 Line of Credit Alternate Base Rate Minimum	Jun. 30, 2012 Line of Credit Alternate Base Rate Maximum	Jun. 30, 2012 Line of Credit Prime Rate	Jun. 30, 2012 Line of Credit Federal Funds Effective Rate	Jun. 30, 2012 Line of Credit Adjusted LIBO Rate	Jun. 30, 2012 Line of Credit Adjusted LIBO Rate Minimum
Line of Credit Facility [Line Items]
Senior secured revolving credit facility borrowing base	$ 375,000
Senior secured revolving credit facility	$ 35,000	$ 0	$ 78,000					$ 35,000
Basis spread on variable rate									1.75%	2.75%	0.75%	1.75%		0.50%		1.00%
Description of variable rate basis													the Prime Rate	the Federal Funds Effective Rate	the Adjusted LIBO Rate
Commitment fee on unused portion of the borrowing base				0.50%
Current Ratio Covenant				1
Ratio Of Consolidated Net Debt To Consolidated EBITDAX Covenant				4.5
Days to elect method to eliminate borrowings in excess of borrowing base				10 days
Days to eliminate borrowings in excess of borrowing base					30 days	30 days	30 days
Months over which borrowings in excess of borrowing base may be repaid in equal monthly installments					6 months