Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Components of income tax benefit
Current tax expense	$ 343,252
Deferred tax benefit	(35,062,841)	(8,098,357)	(16,607,139)
Income tax benefit	34,719,589	8,098,357	16,607,139
Reconciliation of effective income tax rates by applying the federal statutory rate to the income and loss
Federal statutory rate (as a percent)	35.00%	35.00%	35.00%
Loss before income taxes	(126,710,944)	(23,943,739)	(47,452,036)
Income tax benefit at statutory rate	44,348,830	8,380,309	16,608,213
Valuation allowance	(10,197,845)
Adjustment to NOL carryforward			(261,154)
Effect for permanent items	(11,496)	(17,306)	(23,699)
State taxes and other	580,100	(264,646)	283,779
Income tax benefit	34,719,589	8,098,357	16,607,139
Deferred tax assets
Net operating loss carryforwards	38,988,438	59,443,480
Oil and gas properties	19,163,931
Deferred compensation	8,057,657	7,177,942
Income tax credits	347,737	281,424
Deferred tax assets before valuation allowance	66,557,763	66,902,846
Valuation allowance	(13,290,201)	(3,238,656)
Net deferred tax assets	53,267,562	63,664,190
Deferred tax liabilities
Oil and gas properties		(44,780,151)
Derivative instruments	(532,795)	(1,349,679)
Other	(563,451)	(425,726)
Deferred tax liabilities	(1,096,246)	(46,555,556)
Net deferred tax assets	52,171,316	17,108,634
Income taxes
Increase in valuation allowance against NOL	29,100,000
Partial valuation allowance against NOL carryforwards not impacted by limitations, tax adjusted	10,200,000
Changes to unrecognized tax benefits
Balance at the beginning of the period	518,219
Balance at the end of the period	518,219	518,219
Federal
Income taxes
Net operating loss carryforwards	110,700,000
Increase in valuation allowance against NOL	29,100,000
Valuation allowance against NOL	38,000,000
Tax-adjusted valuation allowance against NOL	13,300,000
Number of parts of valuation allowance against NOL	2
Full valuation allowance against not utilizable NOL carryforwards	8,800,000
Tax Adjusted Full Valuation Allowance Against not Utilizable Operating (Loss) Carryforwards	3,100,000
Partial valuation allowance against NOL carryforwards not impacted by limitations	29,100,000
Partial valuation allowance against NOL carryforwards not impacted by limitations, tax adjusted	10,200,000
NOL carryforwards subject to expiration at various dates beginning in 2013 and ending in 2033	110,700,000
NOL carryforwards expiring between 2013 and 2016	8,800,000
NOL carryforwards expiring at various dates beginning in 2026 and ending in 2033	101,900,000
State
Income taxes
Net operating loss carryforwards	$ 6,800,000