Derivatives and Concentration of Credit Risk - Derivatives related to production (Detail) - Derivatives related to production - Short Position [Member] BTU / d in Thousands	12 Months Ended
	Dec. 31, 2019 bbl / d BTU / d $ / bbl $ / MMBtu	[2]
Price Risk Derivative [Member] | 2020 [Member] | Crude Oil [Member] | WTI
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	65,129	[1],[3]
Underlying, Derivative Energy Measure	57.07	[3],[4]
Basis Swap [Member] | 2020 [Member] | Crude Oil [Member] | Midland-Cushing [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	7,486	[1]
Underlying, Derivative	(1.31)	[4]
Basis Swap [Member] | 2020 [Member] | Crude Oil [Member] | Brent/WTI [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	5,000	[1]
Underlying, Derivative Energy Measure	8.36	[4]
Basis Swap [Member] | 2020 [Member] | Natural Gas | Waha [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | BTU / d	60	[1]
Underlying, Derivative | $ / MMBtu	(0.79)	[4]
Basis Swap [Member] | 2021 [Member] | Crude Oil [Member] | Brent/WTI [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	1,000	[1]
Underlying, Derivative Energy Measure	8.00	[4]
Basis Swap [Member] | 2021 [Member] | Natural Gas | Waha [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | BTU / d	70	[1]
Underlying, Derivative | $ / MMBtu	(0.59)	[4]
Basis Swap [Member] | 2022 [Member] | Crude Oil [Member] | Brent/WTI [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	1,000	[1]
Underlying, Derivative Energy Measure	7.75	[4]
Basis Swap [Member] | 2022 [Member] | Natural Gas | Waha [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | BTU / d	70	[1]
Underlying, Derivative | $ / MMBtu	(0.57)	[4]
Basis Swap [Member] | 2023 [Member] | Natural Gas | Waha [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | BTU / d	70	[1]
Underlying, Derivative | $ / MMBtu	(0.51)	[4]
Swaption [Member] | 2021 [Member] | Crude Oil [Member] | WTI
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	20,000	[1]
Underlying, Derivative Energy Measure	57.02	[4]
Put Option [Member] | 2020 [Member] | Crude Oil [Member] | WTI
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount | bbl / d	20,000	[1]
Put Option [Member] | 2020 [Member] | Minimum | Crude Oil [Member] | WTI
Derivative [Line Items]
Underlying, Derivative Energy Measure	53.33	[4]
Put Option [Member] | 2020 [Member] | Maximum | Crude Oil [Member] | WTI
Derivative [Line Items]
Underlying, Derivative Energy Measure	63.48	[4]

[1] Crude oil volumes are reported in Bbl/day and natural gas volumes are reported in BBtu/day.

[2] Derivatives related to crude oil production are fixed price swaps settled on the business day average, basis swaps, fixed price calls, collars or swaptions. The derivatives related to natural gas production are fixed price swaps, basis swaps, fixed price calls and swaptions. In connection with swaps, we may sell call options or swaptions to the swap counterparties in exchange for receiving premium hedge prices on the swaps. The sold call or swaption establishes a maximum price we will receive for the volumes under contract and are financially settled. Basis swaps for the Nymex CMA (Calendar Monthly Average) Roll location are pricing adjustments to the trade month versus the delivery month for contract pricing. Basis swaps for the Brent/WTI location are priced off the Brent and WTI futures spread.

[3] Fixed Price Swaps include hedges related to a new partnership created to fund non-operated interests

[4] The weighted average price for crude oil is reported in $/Bbl and the natural gas is reported in $/MMBtu.(d) Fixed Price Swaps include hedges related to a new partnership created to fund non-operated interests.