Commodity Price Risk Activities - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017 bbl / d MMBTU / d DeliveryObligation bbl
Derivative [Line Items]
Number of open physical obligations | DeliveryObligation	0
Oil Derivative Contracts, 2018
Derivative [Line Items]
Derivative contracts, aggregate volume | bbl	1,713,500
Derivative contracts, aggregate volume per day | bbl / d	4,695
Oil Derivative Contracts, 2019
Derivative [Line Items]
Derivative contracts, aggregate volume | bbl	1,471,100
Derivative contracts, aggregate volume per day | bbl / d	4,030
Oil Derivative Contracts, 2020
Derivative [Line Items]
Derivative contracts, aggregate volume | bbl	203,600
Derivative contracts, aggregate volume per day | bbl / d	1,119
Natural Gas Derivative Contracts, 2018
Derivative [Line Items]
Derivative contracts, aggregate volume per day | MMBTU / d	5,000