Derivative Financial Instruments (Details) bbl in Thousands, MMBTU in Thousands			2 Months Ended
		Dec. 31, 2017 MMBTU $ / EnergyContent $ / Barrels bbl	Feb. 14, 2018 $ / Barrels bbl
NYMEX Oil Swap Contract First Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,075
Derivative, Swap Type, Average Fixed Price | $ / Barrels		50.16
NYMEX Oil Swap Contract Second Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,534
Derivative, Swap Type, Average Fixed Price | $ / Barrels		49.57
NYMEX Oil Swap Contract Third Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,769
Derivative, Swap Type, Average Fixed Price | $ / Barrels		49.77
NYMEX Oil Swap Contract Fourth Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,894
Derivative, Swap Type, Average Fixed Price | $ / Barrels		49.87
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		8,212
NYMEX Oil Collar Contract First Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,445
Derivative, Floor Price | $ / Barrels		50.00
Derivative, Ceiling Price | $ / Barrels		59.07
NYMEX Oil Collar Contract Second Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,459
Derivative, Floor Price | $ / Barrels		50.00
Derivative, Ceiling Price | $ / Barrels		59.03
NYMEX Oil Collar Contract Third Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,948
Derivative, Floor Price | $ / Barrels		50.00
Derivative, Ceiling Price | $ / Barrels		58.61
NYMEX Oil Collar Contract Fourth Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		2,222
Derivative, Floor Price | $ / Barrels		50.00
Derivative, Ceiling Price | $ / Barrels		58.44
NYMEX Oil Collar Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		5,908
Derivative, Floor Price | $ / Barrels		47.65
Derivative, Ceiling Price | $ / Barrels		59.19
NYMEX Oil Collar Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		12,982
Oil Basis Swap Contract First Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		2,113
Weighted-Average Contract Price | $ / Barrels	[1]	(1.15)
Oil Basis Swap Contract Second Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		2,392
Weighted-Average Contract Price | $ / Barrels	[1]	(1.03)
Oil Basis Swap Contract Third Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		3,018
Weighted-Average Contract Price | $ / Barrels	[1]	(1.06)
Oil Basis Swap Contract Fourth Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		3,327
Weighted-Average Contract Price | $ / Barrels	[1]	(1.08)
Oil Basis Swap Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		5,788
Weighted-Average Contract Price | $ / Barrels	[1]	(1.09)
Oil Basis Swap [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		16,638
Gas Swaps Contract First Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent		3.55
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | MMBTU		28,910
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU		(8,121)
Derivative, Swap Type, Weighted-Average Fixed Price, Purchased Volumes | $ / EnergyContent		4.34
Derivative, Nonmonetary Notional Amount, Energy Measure, Net Volumes | MMBTU	[2]	20,789
Gas Swaps Contract Second Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent		3.31
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | MMBTU		23,507
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU		(7,795)
Derivative, Swap Type, Weighted-Average Fixed Price, Purchased Volumes | $ / EnergyContent		4.24
Derivative, Nonmonetary Notional Amount, Energy Measure, Net Volumes | MMBTU	[2]	15,712
Gas Swaps Contract Third Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent		3.29
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | MMBTU		24,627
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU		(7,480)
Derivative, Swap Type, Weighted-Average Fixed Price, Purchased Volumes | $ / EnergyContent		4.23
Derivative, Nonmonetary Notional Amount, Energy Measure, Net Volumes | MMBTU	[2]	17,147
Gas Swaps Contract Fourth Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent		3.29
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | MMBTU		25,856
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU		(7,210)
Derivative, Swap Type, Weighted-Average Fixed Price, Purchased Volumes | $ / EnergyContent		4.27
Derivative, Nonmonetary Notional Amount, Energy Measure, Net Volumes | MMBTU	[2]	18,646
Gas Swaps Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent		3.76
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | MMBTU		41,394
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU		(24,415)
Derivative, Swap Type, Weighted-Average Fixed Price, Purchased Volumes | $ / EnergyContent		4.34
Derivative, Nonmonetary Notional Amount, Energy Measure, Net Volumes | MMBTU	[2]	16,979
Gas Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | MMBTU	[2]	144,294
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU	[2]	(55,021)
Derivative, Nonmonetary Notional Amount, Energy Measure, Net Volumes | MMBTU	[2]	89,273
IF HSC [Member]
Derivative Financial Instruments
Index percent of natural gas fixed swaps		99.00%
IF El Paso Permian [Member]
Derivative Financial Instruments
Index percent of natural gas fixed swaps		1.00%
OPIS Purity Ethane Mont Belvieu [Member] | NGL Swaps Contract First Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		923
Derivative, Swap Type, Average Fixed Price | $ / Barrels		10.90
OPIS Purity Ethane Mont Belvieu [Member] | NGL Swaps Contract Second Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		915
Derivative, Swap Type, Average Fixed Price | $ / Barrels		10.87
OPIS Purity Ethane Mont Belvieu [Member] | NGL Swaps Contract Third Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,033
Derivative, Swap Type, Average Fixed Price | $ / Barrels		10.99
OPIS Purity Ethane Mont Belvieu [Member] | NGL Swaps Contract Fourth Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,146
Derivative, Swap Type, Average Fixed Price | $ / Barrels		11.18
OPIS Purity Ethane Mont Belvieu [Member] | NGL Swaps Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		3,533
Derivative, Swap Type, Average Fixed Price | $ / Barrels		12.31
OPIS Purity Ethane 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 Purity Ethane Mont Belvieu [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		8,089
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract First Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		629
Derivative, Swap Type, Average Fixed Price | $ / Barrels		25.39
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Second Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		554
Derivative, Swap Type, Average Fixed Price | $ / Barrels		24.94
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Third Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		610
Derivative, Swap Type, Average Fixed Price | $ / Barrels		24.27
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		671
Derivative, Swap Type, Average Fixed Price | $ / Barrels		24.39
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		1,503
Derivative, Swap Type, Average Fixed Price | $ / Barrels		27.83
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
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		3,967
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract First Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		206
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.83
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Second Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		84
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.69
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Third Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		93
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.70
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		102
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.70
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		154
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.64
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
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		639
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract First Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		167
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.76
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Second Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		66
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.07
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Third Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		70
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.07
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		76
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.07
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		117
Derivative, Swap Type, Average Fixed Price | $ / Barrels		35.70
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
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		496
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract First Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		188
Derivative, Swap Type, Average Fixed Price | $ / Barrels		49.40
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract Second Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		109
Derivative, Swap Type, Average Fixed Price | $ / Barrels		49.57
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract Third Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		118
Derivative, Swap Type, Average Fixed Price | $ / Barrels		49.56
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		129
Derivative, Swap Type, Average Fixed Price | $ / Barrels		49.57
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		197
Derivative, Swap Type, Average Fixed Price | $ / Barrels		50.93
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
OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume		741
Subsequent Event [Member] | OPIS Natural Gasoline Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2018 [Member]
Derivative Financial Instruments
Derivative, Nonmonetary Notional Amount, Volume			228
Derivative, Swap Type, Average Fixed Price | $ / Barrels			53.34

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

[2] Total net volumes of gas swaps are comprised of IF HSC (99%) and IF El Paso Permian (1%).