Long-Term Debt and Notes Payable - Narratives (Details) (USD $)	3 Months Ended		9 Months Ended				0 Months Ended		0 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2013 Senior Loans Senior Term Loans due March 31, 2014 to December 17, 2017	Sep. 02, 2014 Syndicated Credit Facility Credit Facility, September 2, 2014	Sep. 02, 2014 Syndicated Credit Facility Credit Facility, September 2, 2014	Oct. 30, 2012 Syndicated Credit Facility Credit Facility, October 30, 2012
Debt Instrument [Line Items]
Senior terms loan						$ 600,000,000
Cross default provision, threshold amount	10,000,000		10,000,000
Maximum borrowing capacity								1,500,000,000	1,250,000,000.00
Debt Instrument, Term							5 years		5 years
Initial borrowing base	1,500,000,000		1,500,000,000		1,250,000,000			2,100,000,000
Credit facility cross default provision, threshold amount	75,000,000		75,000,000
Interest expense	11,522,000	10,149,000	27,374,000	30,232,000
Capitalized interest expense	$ 0	$ 0	$ 37,000	$ 200,000
Debt covenant, Debt to EBITDAX Ratio								4.0
Debt covenant, Current assets to Current Liabilities Ratio								1.0
Debt covenant, Minimum net present value of proved reserves to consolidated debt, Ratio								1.50
Percent, Loan Limit								10.00%