Commodity Derivative Positions (Detail)	Dec. 31, 2019 bbl $ / bbl
Fourth Quarter 2021 [Member] [Domain] | Put Option [Member] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	44.00
Derivative, Nonmonetary Notional Amount | bbl	1,630
Fourth Quarter 2021 [Member] [Domain] | Swap [Member] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	55.50
Derivative, Nonmonetary Notional Amount | bbl	1,630
Third Quarter 2021 [Member] [Domain] | Put Option [Member] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	44.00
Derivative, Nonmonetary Notional Amount | bbl	1,630
Third Quarter 2021 [Member] [Domain] | Swap [Member] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	55.50
Derivative, Nonmonetary Notional Amount | bbl	1,630
Second Quarter 2021 [Member] [Domain] | 3-Way Collars [Domain] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Floor Price	55.00
Derivative, Cap Price	58.00
Derivative, Nonmonetary Notional Amount | bbl	1,648
Second Quarter 2021 [Member] [Domain] | Put Option [Member] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	44.00
Derivative, Nonmonetary Notional Amount | bbl	4,945
Second Quarter 2021 [Member] [Domain] | Swap [Member] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	55.89
Derivative, Nonmonetary Notional Amount | bbl	3,297
First Quarter 2021 [Member] [Domain] | 3-Way Collars [Domain] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Floor Price	55.00
Derivative, Cap Price	58.00
Derivative, Nonmonetary Notional Amount | bbl	1,667
First Quarter 2021 [Member] [Domain] | Put Option [Member] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	44.00
Derivative, Nonmonetary Notional Amount | bbl	5,000
First Quarter 2021 [Member] [Domain] | Swap [Member] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	55.89
Derivative, Nonmonetary Notional Amount | bbl	3,333
Fourth Quarter 2020 [Member] | Swap [Member] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	54.77
Derivative, Nonmonetary Notional Amount | bbl	10,630
Fourth Quarter 2020 [Member] | Swap [Member] | MEH [Member]
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	61.03
Derivative, Nonmonetary Notional Amount | bbl	2,000
Third Quarter 2020 [Member] | 2-Way Collars [Domain] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Floor Price	55.00
Derivative, Cap Price	58.42
Derivative, Nonmonetary Notional Amount | bbl	4,891
Third Quarter 2020 [Member] | Swap [Member] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	54.77
Derivative, Nonmonetary Notional Amount | bbl	10,630
Third Quarter 2020 [Member] | Swap [Member] | MEH [Member]
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	61.03
Derivative, Nonmonetary Notional Amount | bbl	2,000
Second Quarter 2020 [Member] | 2-Way Collars [Domain] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Floor Price	55.00
Derivative, Cap Price	57.69
Derivative, Nonmonetary Notional Amount | bbl	3,297
Second Quarter 2020 [Member] | Swap [Member] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	54.96
Derivative, Nonmonetary Notional Amount | bbl	12,648
Second Quarter 2020 [Member] | Swap [Member] | MEH [Member]
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	61.03
Derivative, Nonmonetary Notional Amount | bbl	2,000
First Quarter 2020 [Member] | Swap [Member] | Crude Oil
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Floor Price	48.00
Derivative, Cap Price	57.10
Derivative, Swap Type, Fixed Price	55.34
Derivative, Nonmonetary Notional Amount | bbl	15,648
First Quarter 2020 [Member] | Swap [Member] | MEH [Member]
Derivative Instruments Related to Oil and Gas Production [Line Items]
Derivative, Swap Type, Fixed Price	61.03
Derivative, Nonmonetary Notional Amount | bbl	2,000