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Derivative Financial Instruments - Schedule of Notional Amounts and Estimated Fair Values of Commodity Derivative Positions (Detail) bbl in Thousands, MMBTU in Thousands, $ in Thousands | Jun. 30, 2021 USD ($) MMBTU bbl | Dec. 31, 2020 USD ($) MMBTU bbl
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Financial Institution Counterparties [Member] | Oil Commodity Derivative [Member] |  |
Derivative Instruments [Line Items] |  |
Oil/Natural Gas Derivative Assets, Notional Amount | bbl | 4,404 | 3,056
Oil/Natural Gas Derivative Liabilities, Notional Amount | bbl | 10,187 | 6,391
Oil/Natural Gas Derivative Assets, Estimated Fair Value | $ 8,102 | $ 8,341
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value | $ (133,830) | $ (32,112)
Financial Institution Counterparties [Member] | Natural Gas Commodity Derivative [Member] |  |
Derivative Instruments [Line Items] |  |
Oil/Natural Gas Derivative Assets, Notional Amount | MMBTU | 15,562 | 9,281
Oil/Natural Gas Derivative Liabilities, Notional Amount | MMBTU | 37,124 | 15,079
Oil/Natural Gas Derivative Assets, Estimated Fair Value | $ 2,715 | $ 1,529
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value | $ (18,752) | $ (3,265)
Customer Counterparties [Member] | Oil Commodity Derivative [Member] |  |
Derivative Instruments [Line Items] |  |
Oil/Natural Gas Derivative Assets, Notional Amount | bbl | 10,258 | 6,391
Oil/Natural Gas Derivative Liabilities, Notional Amount | bbl | 4,333 | 3,056
Oil/Natural Gas Derivative Assets, Estimated Fair Value | $ 134,834 | $ 32,670
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value | $ (8,094) | $ (8,264)
Customer Counterparties [Member] | Natural Gas Commodity Derivative [Member] |  |
Derivative Instruments [Line Items] |  |
Oil/Natural Gas Derivative Assets, Notional Amount | MMBTU | 37,124 | 17,636
Oil/Natural Gas Derivative Liabilities, Notional Amount | MMBTU | 15,562 | 6,724
Oil/Natural Gas Derivative Assets, Estimated Fair Value | $ 19,065 | $ 3,451
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value | $ (2,711) | $ (1,458)

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