Long-Term Debt--Senior Secured Revolving Credit Facility (Details) (USD $) In Thousands, unless otherwise specified				12 Months Ended							12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Eurodollar Rate Option	Dec. 31, 2013 Line of Credit Quarters	Dec. 31, 2013 Line of Credit Election One	Dec. 31, 2013 Line of Credit Election Two	Dec. 31, 2013 Line of Credit Election Three	Dec. 31, 2013 Line of Credit Minimum	Dec. 31, 2013 Line of Credit Maximum	Oct. 29, 2013 Line of Credit Maximum	Dec. 31, 2013 Line of Credit Eurodollar Rate Option	Dec. 31, 2013 Line of Credit Eurodollar Rate Option Minimum	Dec. 31, 2013 Line of Credit Eurodollar Rate Option Maximum	Dec. 31, 2013 Line of Credit Alternate Base Rate Option Minimum	Dec. 31, 2013 Line of Credit Alternate Base Rate Option Maximum	Dec. 31, 2013 Line of Credit Federal Funds Effective Rate	Dec. 31, 2013 Line of Credit Adjusted LIBO Rate	Oct. 29, 2013 Line of Credit Pre-Amendment	Oct. 29, 2013 Line of Credit Post-Amendment	Oct. 29, 2013 Line of Credit Post-Cabot Acquisition
Line of Credit Facility [Line Items]
Maturity date				Nov. 01, 2017
Borrowing base amount				$ 600,000														$ 500,000	$ 550,000	$ 600,000
Additional Permitted Debt																			300,000
Derivatives permitted on properties to be acquired, as a percentage of anticipated PDP production										80.00%
Permitted Other Debt																		40,000	50,000
Credit facility balance subject to Eurodollar rate	$ 272,000	$ 25,000	$ 272,000
One month interest period											1 month
Two month interest period											2 months
Three month interest period											3 months
Six month interest period											6 months
Basis spread on variable rate												1.50%	1.75%	0.50%	0.75%	0.50%	1.00%
Frequency of periodic interest payment on senior secured revolving credit facility												3 months
Commitment fee on unused portion of the borrowing base								0.375%	0.50%
Current Ratio covenant								1
Ratio Of Consolidated Net Debt To Consolidated EBITDAX covenant									4.50
Number of consecutive quarters used in Consolidated Net Debt to Consolidated EBITDAX ratio calculation				4
Number of days to make election to eliminate borrowings in excess of borrowing base as the result of a redetermination				10 days
Number of days to eliminate borrowings in excess of borrowing base as the result of a redetermination					30 days	30 days	30 days
Period of time over which borrowings in excess of borrowing base can be repaid in equal monthly installments				6 months