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Supplemental Oil and Gas Reserve Information - Unaudited - Additional Information (Detail) | 1 Months Ended | 11 Months Ended | 12 Months Ended
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Dec. 31, 2020 MMBoe | Nov. 19, 2020 MMBoe | Dec. 31, 2020 MBoe | Dec. 31, 2020 | Dec. 31, 2020 MMBoe | Dec. 31, 2020 $ / bbl | Dec. 31, 2020 $ / MMBTU | Dec. 31, 2019 MBoe | Dec. 31, 2019 | Dec. 31, 2019 MMBoe | Dec. 31, 2019 $ / bbl | Dec. 31, 2019 $ / MMBTU | Dec. 31, 2018 MBoe | Dec. 31, 2018 | Dec. 31, 2018 MMBoe | Dec. 31, 2018 $ / bbl | Dec. 31, 2018 $ / MMBTU | Dec. 31, 2017 MMBoe
Reserve Quantities [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net positive (negative) revisions of previous estimates (MMBoe) |  |  | (86,251) |  |  |  |  | (63,349) |  | (63,300) |  |  | (16,850) |  | (16,900) |  |  |
Percentage of net positive (negative) revisions |  |  |  | (30.00%) |  |  |  |  | (20.00%) |  |  |  |  | (5.00%) |  |  |  |
Positive (negative) revisions of previous estimates - proved developed reserves (MMBoe) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (20,200) |  |  |
Additions due to extensions and discoveries (MMBoe) |  |  | 6,021 |  | 6,000.0 |  |  | 63,861 |  | 63,900 |  |  | 38,358 |  | 38,400 |  |  |
Estimated extensions and discoveries of reserves associated with new wells (MMBoe) | MBoe |  |  | 3,200 |  |  |  |  | 10,300 |  |  |  |  | 9,000.0 |  |  |  |  |
Percentage of reserves produced from wells in certain formations |  |  |  |  |  |  |  |  | 60.00% |  |  |  |  | 77.00% |  |  |  |
Additional proved undeveloped reserves (MMBoe) |  |  |  |  | 2,800 |  |  |  |  | 53,600 |  |  |  |  | 29,400 |  |  |
Percentage of proved undeveloped reserves |  |  |  |  |  |  |  |  |  |  |  |  |  | 76.00% |  |  |  |
Divested reserves associated with non-operated properties (MMBoe) | 0 | 0 |  |  |  |  |  | 2,531 |  | 2,500 |  |  | 15,926 |  | 15,900 |  |  |
Purchases of reserves in place (MMBoe) |  |  |  |  |  |  |  |  |  | 0 |  |  | 32,873 |  |  |  |  | 32,900
Unweighted arithmetic average first-day-of-the-month prices for oil (in dollars per Bbl) | $ / bbl |  |  |  |  |  | 39.54 |  |  |  |  | 55.85 |  |  |  |  | 65.66 |  |
Unweighted arithmetic average first-day-of-the-month prices for natural gas (in dollars per MMBtu) | $ / MMBTU |  |  |  |  |  |  | 2.03 |  |  |  |  | 2.62 |  |  |  |  | 3.16 |
Revision of Previous Estimate Due to Realized Prices |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net positive (negative) revisions of previous estimates (MMBoe) |  |  |  |  | (29.3) |  |  |  |  | 11,200 |  |  |  |  | 14,400 |  |  |
Positive (negative) revisions of previous estimates - proved developed reserves (MMBoe) |  |  |  |  | (31.9) |  |  |  |  | (9,600) |  |  |  |  | 12,200 |  |  |
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe) |  |  |  |  | 2.6 |  |  |  |  |  |  |  |  |  | 2,200 |  |  |
Revision Due to Performance |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net positive (negative) revisions of previous estimates (MMBoe) |  |  |  |  |  |  |  |  |  | (51,200) |  |  |  |  | (42,300) |  |  |
Positive (negative) revisions of previous estimates - proved developed reserves (MMBoe) |  |  |  |  |  |  |  |  |  | (30,200) |  |  |  |  | (33,000.0) |  |  |
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe) |  |  |  |  |  |  |  |  |  | 21,100 |  |  |  |  | (9,300) |  |  |
Revision of Previous Estimate Due to (Mis)Alignment With Development Plan |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net positive (negative) revisions of previous estimates (MMBoe) |  |  |  |  | (60.1) |  |  |  |  | (7,600) |  |  |  |  | (9,400) |  |  |
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe) |  |  |  |  | (54.5) |  |  |  |  | (7,000.0) |  |  |  |  | (9,400) |  |  |
Revision of Previous Estimate Due to Lower Operating Expenses |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net positive (negative) revisions of previous estimates (MMBoe) |  |  |  |  | (1.5) |  |  |  |  | (6,700) |  |  |  |  |  |  |  |
Positive (negative) revisions of previous estimates - proved developed reserves (MMBoe) |  |  |  |  |  |  |  |  |  | 5,100 |  |  |  |  |  |  |  |
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe) |  |  |  |  |  |  |  |  |  | (1,700) |  |  |  |  |  |  |  |
Revisions Due to Addition of Proved Undeveloped Reserves (PUDs) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net positive (negative) revisions of previous estimates (MMBoe) |  |  |  |  | (5.6) |  |  |  |  |  |  |  |  |  | 14,700 |  |  |
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 14,700 |  |  |
Revision of Previous Estimate Due to Ownership Adjustments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net positive (negative) revisions of previous estimates (MMBoe) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,400 |  |  |
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe) |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,600 |  |  |
Bakken or Three Forks Formations Area |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of reserves produced from wells in certain formations |  |  |  | 1.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of proved undeveloped reserves |  |  |  |  |  |  |  |  | 63.00% |  |  |  |  |  |  |  |  |
Delaware Basin |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reserve Quantities [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of reserves produced from wells in certain formations |  |  |  | 99.00% |  |  |  |  | 40.00% |  |  |  |  | 23.00% |  |  |  |
Percentage of proved undeveloped reserves |  |  |  |  |  |  |  |  | 37.00% |  |  |  |  | 24.00% |  |  |  |

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