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Variable Interest Entities - Investments (Detail) - USD ($) $ in Thousands |  | 1 Months Ended | 3 Months Ended | 6 Months Ended |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 02, 2022 | Feb. 28, 2025 | Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024 | Aug. 06, 2025 | Mar. 31, 2025 | Dec. 31, 2024 | Mar. 31, 2024 | Feb. 29, 2024 | Dec. 31, 2023
Investments in and Advances to Affiliates [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Contributions to equity method investments |  |  | $ 513 | $ 665 | $ 1,391 | $ 1,290 |  |  |  |  |  |
Carrying value of investment |  |  | 29,628 | $ 45,088 | 29,628 | $ 45,088 |  | $ 33,555 | $ 35,532 | $ 45,693 |  | $ 46,503
NGP ET IV |  |  |  |  |  |  |  |  |  |  |  |
Investments in and Advances to Affiliates [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Carrying value of investment |  |  | 8,000 |  | 8,000 |  |  |  | $ 8,800 |  |  |
NGP ET IV |  |  |  |  |  |  |  |  |  |  |  |
Investments in and Advances to Affiliates [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Funding commitment | $ 25,000 |  |  |  |  |  |  |  |  |  |  |
Contributions to investee to date |  |  | $ 10,900 |  | $ 10,900 |  |  |  |  |  |  |
Gavin Generation |  |  |  |  |  |  |  |  |  |  |  |
Investments in and Advances to Affiliates [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Funding commitment |  | $ 25,000 |  |  |  |  |  |  |  |  | $ 25,000 |
Gavin Generation | Subsequent event |  |  |  |  |  |  |  |  |  |  |  |
Investments in and Advances to Affiliates [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Contributions to investee to date |  |  |  |  |  |  | $ 22,100 |  |  |  |  |
VIE, Not Primary Beneficiary | NGP ET IV | NGP ET IV |  |  |  |  |  |  |  |  |  |  |  |
Investments in and Advances to Affiliates [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage by limited partners | 3.60% |  |  |  |  |  |  |  |  |  |  |
VIE, Not Primary Beneficiary | Gavin Generation | Gavin Generation |  |  |  |  |  |  |  |  |  |  |  |
Investments in and Advances to Affiliates [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Ownership percentage by limited partners |  | 5.40% |  |  |  |  |  |  |  |  |  |

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- Definition Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions. + References No definition available. + Details
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