Derivative Financial Instruments (Details)	Dec. 31, 2013 Crude Oil [Member] bbl	Dec. 31, 2013 Natural Gas [Member] MMBTU	Dec. 31, 2013 Natural Gas Liquids [Member] bbl	Dec. 31, 2013 NYMEX WTI [Member]	Dec. 31, 2013 Argus LLS [Member]	Dec. 31, 2013 IF El Paso Permian [Member]	Dec. 31, 2013 IF HSC [Member]	Dec. 31, 2013 IF NGPL TXOK [Member]	Dec. 31, 2013 IF NNG Ventura [Member]	Sep. 30, 2013 IF NNG Ventura [Member]	Dec. 31, 2013 IF PEPL [Member]	Dec. 31, 2013 IF Reliant N/S [Member]	Dec. 31, 2013 IF NGPL MidCont [Member]	Dec. 31, 2013 IF TETCO STX [Member]	Dec. 31, 2013 OPIS IsoButane Mt Belv Non TET [Member]	Dec. 31, 2013 OPIS Natural Gasoline Mt Belv Non TET [Member]	Dec. 31, 2013 OPIS NButane Mt Belv Non TET [Member]	Dec. 31, 2013 OPIS Propane Mt Belv TET [Member]	Dec. 31, 2013 Swap [Member] Crude Oil [Member] bbl	Dec. 31, 2013 Swap [Member] Natural Gas [Member] MMBTU	Dec. 31, 2013 Swap [Member] Natural Gas Liquids [Member] bbl	Dec. 31, 2013 Collar [Member] Crude Oil [Member] bbl	Dec. 31, 2013 Collar [Member] Natural Gas [Member] MMBTU	Dec. 31, 2013 First Quarter of 2014 [Member] Swap [Member] Crude Oil [Member] bbl	Dec. 31, 2013 First Quarter of 2014 [Member] Swap [Member] Natural Gas [Member] MMBTU	Dec. 31, 2013 First Quarter of 2014 [Member] Swap [Member] Natural Gas Liquids [Member] bbl	Dec. 31, 2013 First Quarter of 2014 [Member] Collar [Member] Crude Oil [Member] bbl	Dec. 31, 2013 First Quarter of 2014 [Member] Collar [Member] Natural Gas [Member] MMBTU	Dec. 31, 2013 Second Quarter of 2014 [Member] Swap [Member] Crude Oil [Member] bbl	Dec. 31, 2013 Second Quarter of 2014 [Member] Swap [Member] Natural Gas [Member] MMBTU	Dec. 31, 2013 Second Quarter of 2014 [Member] Swap [Member] Natural Gas Liquids [Member] bbl	Dec. 31, 2013 Second Quarter of 2014 [Member] Collar [Member] Crude Oil [Member] bbl	Dec. 31, 2013 Second Quarter of 2014 [Member] Collar [Member] Natural Gas [Member] MMBTU	Dec. 31, 2013 Third Quarter of 2014 [Member] Swap [Member] Crude Oil [Member] bbl	Dec. 31, 2013 Third Quarter of 2014 [Member] Swap [Member] Natural Gas [Member] MMBTU	Dec. 31, 2013 Third Quarter of 2014 [Member] Swap [Member] Natural Gas Liquids [Member] bbl	Dec. 31, 2013 Third Quarter of 2014 [Member] Collar [Member] Crude Oil [Member] bbl	Dec. 31, 2013 Fourth Quarter of 2014Member] Swap [Member] Crude Oil [Member] bbl	Dec. 31, 2013 Fourth Quarter of 2014Member] Swap [Member] Natural Gas [Member] MMBTU	Dec. 31, 2013 Fourth Quarter of 2014Member] Swap [Member] Natural Gas Liquids [Member] bbl	Dec. 31, 2013 Fourth Quarter of 2014Member] Collar [Member] Crude Oil [Member] bbl	Dec. 31, 2013 2015 [Member] Swap [Member] Crude Oil [Member] bbl	Dec. 31, 2013 2015 [Member] Swap [Member] Natural Gas [Member] MMBTU	Dec. 31, 2013 2015 [Member] Collar [Member] Crude Oil [Member] bbl	Dec. 31, 2013 2015 [Member] Collar [Member] Natural Gas [Member] MMBTU	Dec. 31, 2013 2016 [Member] Swap [Member] Crude Oil [Member] bbl	Dec. 31, 2013 2016 [Member] Swap [Member] Natural Gas [Member] MMBTU	Dec. 31, 2013 2017 [Member] Swap [Member] Natural Gas [Member] MMBTU	Dec. 31, 2013 2018 [Member] Swap [Member] Natural Gas [Member] MMBTU	Feb. 12, 2014 Subsequent Event [Member] Crude Oil [Member] bbl	Feb. 12, 2014 Subsequent Event [Member] Natural Gas [Member] MMBTU	Feb. 12, 2014 Subsequent Event [Member] Natural Gas Liquids [Member] bbl	Feb. 12, 2014 Subsequent Event [Member] IF NNG Ventura [Member]	Feb. 12, 2014 Subsequent Event [Member] OPIS Natural Gasoline Mt Belv Non TET [Member]	Feb. 12, 2014 Subsequent Event [Member] OPIS Propane Mt Belv TET [Member]	Feb. 12, 2014 Subsequent Event [Member] IF CIG N System [Member]	Feb. 12, 2014 Subsequent Event [Member] Swap [Member] Natural Gas [Member] MMBTU	Feb. 12, 2014 Subsequent Event [Member] Swap [Member] Natural Gas Liquids [Member] bbl	Feb. 12, 2014 Subsequent Event [Member] First Quarter of 2014 [Member] Swap [Member] Natural Gas [Member] MMBTU	Feb. 12, 2014 Subsequent Event [Member] First Quarter of 2014 [Member] Swap [Member] Natural Gas Liquids [Member] bbl	Feb. 12, 2014 Subsequent Event [Member] Second Quarter of 2014 [Member] Swap [Member] Natural Gas [Member] MMBTU	Feb. 12, 2014 Subsequent Event [Member] Second Quarter of 2014 [Member] Swap [Member] Natural Gas Liquids [Member] bbl	Feb. 12, 2014 Subsequent Event [Member] Third Quarter of 2014 [Member] Swap [Member] Natural Gas [Member] MMBTU	Feb. 12, 2014 Subsequent Event [Member] Third Quarter of 2014 [Member] Swap [Member] Natural Gas Liquids [Member] bbl	Feb. 12, 2014 Subsequent Event [Member] Fourth Quarter of 2014Member] Swap [Member] Natural Gas [Member] MMBTU	Feb. 12, 2014 Subsequent Event [Member] Fourth Quarter of 2014Member] Swap [Member] Natural Gas Liquids [Member] bbl	Feb. 12, 2014 Subsequent Event [Member] 2015 [Member] Swap [Member] Natural Gas [Member] MMBTU	Feb. 12, 2014 Subsequent Event [Member] 2016 [Member] Swap [Member] Natural Gas [Member] MMBTU
Derivative Financial Instruments
Portion of future oil and NGL production included in derivative contracts	18,800,000		2,500,000																12,452,000		2,549,000	6,387,000		2,600,000		913,000	694,000		2,373,000		565,000	431,000		973,000		544,000	973,000	891,000		527,000	923,000	2,911,000		3,366,000		2,704,000				17,500,000		4,000,000						1,797,000		516,000		531,000		416,000		334,000
Portion of Gas Production Covered Under Derivative Contract		265,900,000																		245,704,000			20,214,000		33,651,000			1,540,000		25,729,000			4,194,000		26,398,000				23,965,000				63,317,000		14,480,000		39,014,000	23,430,000	10,200,000		237,900,000						2,490,000		261,000		365,000		341,000		321,000		1,133,000	69,000
Gas Derivative Contracts Settled Early																																																			18,000,000
Weighted- Average Contract Price																								96.92	4.25	59.72			94.95	3.96	63.22			95.25	4.01	62.34		95.16	4.01	61.57		89.06	4.03			85.19	4.18	4.21	4.31										4.39	54.85	3.84	52.53	3.89	52.47	3.97	52.52	3.72	4.12
Index percent of oil fixed swap				97.00%	3.00%
Weighted- Average Floor Price																											80.97	4.39				85.00	4.38				85.00				85.00			85.00	3.96
Weighted- Average Ceiling Price																											115.07	5.58				102.50	5.29				102.58				102.63			94.25	4.30
Index percent of natural gas fixed swaps						3.00%	77.00%	3.00%		2.00%	6.00%	8.00%	1.00%																																								30.00%			70.00%
Index percent of natural gas collars						2.00%	57.00%	3.00%	5.00%		7.00%	14.00%		12.00%
Index percent of NGL fixed swaps															2.00%	34.00%	3.00%	61.00%																																				17.00%	83.00%