Derivative Financial Instruments (Details) bbl in Thousands, MMBTU in Thousands				1 Months Ended	12 Months Ended
		Sep. 30, 2017 MMBTU $ / EnergyContent $ / Barrels bbl		Nov. 03, 2017 bbl	Dec. 31, 2016 MMBTU $ / EnergyContent	Oct. 26, 2017 $ / Barrels
NYMEX Oil Swap Contract Fourth Quarter 2017 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,510
Derivative, Swap Type, Average Fixed Price | $ / Barrels		47.11
NYMEX Oil Swap Contract 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		6,272
Derivative, Swap Type, Average Fixed Price | $ / Barrels		49.82
NYMEX Oil Swap Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,940
Derivative, Swap Type, Average Fixed Price | $ / Barrels		50.70
NYMEX Oil Swap Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		9,722
NYMEX Oil Collar Contract Fourth Quarter 2017 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,086
Derivative, Floor Price | $ / Barrels		47.51
Derivative, Cap Price | $ / Barrels		56.05
NYMEX Oil Collar Contract 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		5,030
Derivative, Floor Price | $ / Barrels		50.00
Derivative, Cap Price | $ / Barrels		58.07
NYMEX Oil Collar Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		3,128
Derivative, Floor Price | $ / Barrels		50.00
Derivative, Cap Price | $ / Barrels		58.84
NYMEX Oil Collar Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		9,244
Oil Basis Swap Contract Fourth Quarter 2017 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,856
Derivative, Swap Type, Average Fixed Price | $ / Barrels	[1]	(1.50)
Oil Basis Swap Contract 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		8,734
Derivative, Swap Type, Average Fixed Price | $ / Barrels	[1]	(1.27)
Oil Basis Swap Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		3,963
Derivative, Swap Type, Average Fixed Price | $ / Barrels	[1]	(1.45)
Oil Basis Swap [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		14,553
Gas Swaps Contract Fourth Quarter 2017 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent		3.98
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU		22,001
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU		0
Derivative, Swap Type, Average Fixed Price, Purchased Volumes | $ / EnergyContent		0.00
Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes | MMBTU		22,001
Gas Swaps Contract 2018 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent		3.37
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU		102,900
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU	[2]	(30,606)
Derivative, Swap Type, Average Fixed Price, Purchased Volumes | $ / EnergyContent		4.27
Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes | MMBTU		72,294
Gas Swaps Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent		3.76
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU		41,394
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU	[2]	(24,415)
Derivative, Swap Type, Average Fixed Price, Purchased Volumes | $ / EnergyContent		4.34
Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes | MMBTU		16,979
Gas Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	[3]	166,295
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU		(55,021)	[2],[3]		(55,021)
Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes | MMBTU	[3]	111,274
Gas Swaps Contract 2017 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent					4.43
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | MMBTU					38,600
IF El Paso Permian [Member]
Derivative Financial Instruments
Index percent of natural gas fixed swaps		1.00%
IF HSC [Member]
Derivative Financial Instruments
Index percent of natural gas fixed swaps		98.00%
IF NNG Ventura [Member]
Derivative Financial Instruments
Index percent of natural gas fixed swaps		1.00%
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract Fourth Quarter 2017 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		966
Derivative, Swap Type, Average Fixed Price | $ / Barrels		9.65
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		4,017
Derivative, Swap Type, Average Fixed Price | $ / Barrels		11.00
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		3,112
Derivative, Swap Type, Average Fixed Price | $ / Barrels		12.27
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		539
Derivative, Swap Type, Average Fixed Price | $ / Barrels		11.13
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		8,634
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2017 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		653
Derivative, Swap Type, Average Fixed Price | $ / Barrels		24.24
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		2,464
Derivative, Swap Type, Average Fixed Price | $ / Barrels		24.74
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,036
Derivative, Swap Type, Average Fixed Price | $ / Barrels		26.49
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		0
Derivative, Swap Type, Average Fixed Price | $ / Barrels		0.00
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		4,153
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2017 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		214
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.29
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		391
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.14
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		0
Derivative, Swap Type, Average Fixed Price | $ / Barrels		0.00
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		0
Derivative, Swap Type, Average Fixed Price | $ / Barrels		0.00
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		605
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2017 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		174
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.60
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		308
Derivative, Swap Type, Average Fixed Price | $ / Barrels		34.72
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		0
Derivative, Swap Type, Average Fixed Price | $ / Barrels		0.00
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		0
Derivative, Swap Type, Average Fixed Price | $ / Barrels		0.00
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		482
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2017 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		203
Derivative, Swap Type, Average Fixed Price | $ / Barrels		48.41
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		427
Derivative, Swap Type, Average Fixed Price | $ / Barrels		48.44
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		0
Derivative, Swap Type, Average Fixed Price | $ / Barrels		0.00
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2020 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		0
Derivative, Swap Type, Average Fixed Price | $ / Barrels		0.00
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		630
Subsequent Event [Member] | Oil Basis Swap Contract 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume				1,400
Derivative, Swap Type, Average Fixed Price | $ / Barrels						(0.33)

[1] Represents the price differential between WTI prices at Midland, Texas and WTI prices at Cushing, Oklahoma.

[2] During 2016, the Company restructured certain of its natural gas derivative contracts by buying fixed price volumes to offset existing 2018 and 2019 fixed price swap contracts totaling 55.0 million MMBtu. The Company then entered into new 2017 fixed price swap contracts totaling 38.6 million MMBtu with a contract price of $4.43 per MMBtu. No other cash or other consideration was included as part of the restructuring.

[3] Total net volumes of natural gas swaps are comprised of IF El Paso Permian (1%), IF HSC (98%), and IF NNG Ventura (1%).