DEBT (Bank Credit Facility) (Details) (Credit Facility, USD $)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 At The End of the Calendar Quarters Ending March 31, 2014, June 30, 2014, and September 30, 2014	Mar. 31, 2014 At the End of the Calendar Quarter Ending December 31, 2014	Mar. 31, 2014 At the End of the Calendar Quarter Ending March 31, 2015	Mar. 31, 2014 At the End of the Calendar Quarter Ending June 30, 2015	Mar. 31, 2014 At the End of the Calendar Quarter Ending September 30, 2015	Mar. 31, 2014 At the End of Any Calendar Quarter Ending After September 30, 2015	Feb. 15, 2013 South Texas	Nov. 25, 2013 Texas Panhandle
Bank Credit Facility
Credit Facility maximum borrowing capacity	$ 500,000,000
Increase in the credit agreement's borrowing capacity available subject to the agreement	300,000,000
Credit Facility maximum borrowing capacity optional expansion	800,000,000
Credit Facility maximum borrowing capacity prior to amendment	1,500,000,000
Borrowing base under the Credit Facility prior to amendment	400,000,000
Borrowing base under the Credit Facility	300,000,000
Credit Facility borrowing capacity reduction as percentage of the stated principal amount of issued senior notes (as a percent)	25.00%
Credit Facility borrowing capacity reduction due to sale of properties with value in excess of this percentage of the borrowing base then in effect (as a percent)	10.00%
Credit Facility borrowing base reduction due to sale of properties									170,000,000	300,000,000
Credit Facility collateral as percentage of present value of the estimated proved oil and gas properties and related assets (as a percent)	75.00%
Credit Facility covenant based on ratio of total debt outstanding to EBITDA, Numerator			5.75	5.50	5.25	5.00	4.75	4.50
Credit Facility covenant based on ratio of total debt outstanding to EBITDA, Denominator			1.00	1.00	1.00	1.00	1.00	1.00
Credit Facility ratio of total debt outstanding to EBITDA	4.46
Credit Facility	0	0
Credit Facility outstanding letters of credit	$ 2,100,000