Financial Risk Management Activities - Additional Information (Detail)	1 Months Ended	3 Months Ended
	Apr. 30, 2017 bbl / d $ / bbl	Mar. 31, 2017 bbl / d $ / bbl
Brent Crude Oil Price Collars
Derivative [Line Items]
Crude oil price collars to hedge, barrels of oil per day | bbl / d		15,000
Floor price		55
Ceiling price		75
Brent Crude Oil Price Collars | Subsequent Event
Derivative [Line Items]
Crude oil price collars to hedge, barrels of oil per day | bbl / d	5,000
Floor price	55
Ceiling price	75
West Texas Intermediate Crude Oil Price Collars | Subsequent Event
Derivative [Line Items]
Crude oil price collars to hedge, barrels of oil per day | bbl / d	60,000
Floor price	50
Ceiling price	70