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Oil and Gas Reserves Information (Unaudited) - Changes in Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Reserves (Detail) - USD ($) $ in Thousands | 5 Months Ended | 7 Months Ended | 12 Months Ended
--- | --- | --- | ---
Dec. 31, 2018 | Aug. 13, 2018 | Dec. 31, 2020 | Dec. 31, 2019
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Line Items] |  |  |  |
Standardized Measure, Beginning of Year | $ 1,317,383 |  | $ 2,913,211 | $ 1,473,840
Net change in sales price, net of production costs | 223,731 |  | (1,858,026) | (716,930)
Development costs incurred during the year which were previously estimated | 112,073 |  | 302,135 | 311,331
Revisions of quantity estimates | 27,090 |  | 215,268 | 16,340
Accretion of discount | 55,692 |  | 326,074 | 175,514
Changes in future development and abandonment costs | 23,139 |  | 313,191 | (93,476)
Changes in timing and other | 9,434 |  | (127,663) | 180,314
Extensions and discoveries | 15,263 |  | 180,624 | 442,099
Acquisitions of minerals in place | 54,143 |  | 0 | 1,813,491
Sales of minerals in place | (42,870) |  | 0 | (51,070)
Sales, net of production costs | (181,218) |  | (612,194) | (580,922)
Net changes in income taxes | (140,020) |  | 283,105 | (57,320)
Standardized Measure, End of Year | 1,473,840 | $ 1,317,383 | $ 1,935,725 | $ 2,913,211
Predecessor |  |  |  |
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves [Line Items] |  |  |  |
Standardized Measure, Beginning of Year | $ 877,987 | 881,544 |  |
Net change in sales price, net of production costs |  | (61,662) |  |
Development costs incurred during the year which were previously estimated |  | 86,086 |  |
Revisions of quantity estimates |  | 19,815 |  |
Accretion of discount |  | 53,413 |  |
Changes in future development and abandonment costs |  | (27,489) |  |
Changes in timing and other |  | (17,723) |  |
Extensions and discoveries |  | 167,986 |  |
Acquisitions of minerals in place |  | 72,738 |  |
Sales of minerals in place |  | (124,083) |  |
Sales, net of production costs |  | (129,991) |  |
Net changes in income taxes |  | (42,647) |  |
Standardized Measure, End of Year |  | $ 877,987 |  |

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