Derivative Commodity Instruments - Derivative Transactions (Details)	9 Months Ended
	Sep. 30, 2016 MBbls Bcf MMgals $ / Mcf $ / bbl $ / gal
2016 | NYMEX Swaps | Crude Oil
Derivatives, Fair Value [Line Items]
Total Hedged Volumes (in MBbl and Bcf) | MBbls	2,282,000
Average Contract Price (dollars per Bbl)	45.23
2016 | WTI/WTI Basis Swaps | Crude Oil
Derivatives, Fair Value [Line Items]
Total Hedged Volumes (in MBbl and Bcf) | MBbls	1,881,000
Average Contract Price (dollars per Bbl)	(1.92)
2016 | WTS/WTI Basis Swaps | Crude Oil
Derivatives, Fair Value [Line Items]
Total Hedged Volumes (in MBbl and Bcf) | MBbls	514,000
Average Contract Price (dollars per Bbl)	(1.64)
2016 | Basin Specific Swaps - Permian | Natural Gas
Derivatives, Fair Value [Line Items]
Total Hedged Volumes (in MBbl and Bcf) | Bcf	1,800,000.0
Average contract price (dollars per Mcf) | $ / Mcf	2.30
2017 | NYMEX Swaps | Crude Oil
Derivatives, Fair Value [Line Items]
Total Hedged Volumes (in MBbl and Bcf) | MBbls	4,080,000
Average Contract Price (dollars per Bbl)	47.97
2017 | NYMEX Three-Way Collars | Crude Oil
Derivatives, Fair Value [Line Items]
Total Hedged Volumes (in MBbl and Bcf) | MBbls	4,440,000
2017 | Ceiling sold price (call) | Crude Oil | Short
Derivatives, Fair Value [Line Items]
Ceiling sold price (call) (dollars per Bbl)	62.11
2017 | Floor Purchased and Sold Price (Put) | Crude Oil | Short
Derivatives, Fair Value [Line Items]
Floor price (dollars per Bbl)	35.00
2017 | Floor Purchased and Sold Price (Put) | Crude Oil | Long
Derivatives, Fair Value [Line Items]
Floor price (dollars per Bbl)	45.00
2017 | Liquids Swaps | Natural Gas Liquids
Derivatives, Fair Value [Line Items]
Total Hedged Volumes (in MBbl and Bcf) | MMgals	45,400,000.0
Average Contract Price (dollars per Bbl) | $ / gal	0.52
2017 | Basin Specific Swaps - Permian | Natural Gas
Derivatives, Fair Value [Line Items]
Total Hedged Volumes (in MBbl and Bcf) | Bcf	14,700,000.0
Average contract price (dollars per Mcf) | $ / Mcf	2.85