COSTS, EXPENSES, AND OTHER (Details) (USD $)	3 Months Ended			1 Months Ended	3 Months Ended	12 Months Ended	15 Months Ended
	Mar. 31, 2014 drilling_rigs	Mar. 31, 2013	Mar. 31, 2014 Credit Facility	Mar. 31, 2013 8 1/2% Senior Notes due 2014	Mar. 31, 2014 Texas Panhandle	Dec. 31, 2013 Texas Panhandle	Mar. 31, 2014 Texas Panhandle	Oct. 31, 2013 Texas Panhandle
Costs, expenses, and other
Accretion of asset retirement obligations	$ 513,000	$ 1,244,000
Write-off of debt issuance costs	3,323,000	0
Loss on debt extinguishment	0	25,223,000		25,223,000
Loss (gain) on asset disposition, net	794,000	0			794,000	(193,000,000)
Rig stacking/lease termination	5,184,000	3,038,000
Other, net	(1,166,000)	(685,000)
Costs, expenses and other	8,648,000	28,820,000
Write-off of Debt Issuance Costs
Credit Facility maximum borrowing capacity prior to amendment			1,500,000,000
Credit Facility maximum borrowing capacity			500,000,000
Loss on Debt Extinguishment
Redeemed Principal Amount of Senior Notes				300,000,000
Redemption Price As Percentage Of Par (as a percent)				107.11%
Call premium on early redemption of notes				21,300,000
Write-off of debt issuance costs and unamortized discount				3,900,000
Interest rate (as a percent)				8.50%
Loss on Asset Disposition, Net
Sales price of oil and natural gas properties								1,000,000,000
Proceeds from sale of oil and natural gas properties							965,100,000
Rig Stacking/Lease Termination
Expense on early-termination of the operating leases on drilling rigs	5,000,000
Number of drilling rigs whose leases were terminated	7
Rig stacking expenses	3,800,000	4,200,000
Cash expenses on drilling rigs related to early termination of leases and rig stacking expenses	8,800,000
Write-off of unamortized gains related to drilling rigs whose leases were terminated	6,100,000
Non-cash write-off of rig-improvements	$ 2,400,000