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Revenue Recognition (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024
Disaggregation of Revenue [Line Items] |  |  |  |
Third-party lessee payment lag for oil and natural gas delivery |  |  | 90 days |
Change in prior period estimate | $ 0.0 | $ 2.3 | $ 0.0 | $ 0.0
Production performance obligations satisfied in prior period, amount recognized | 0.0 | $ 0.0 | 1.5 | $ 0.0
Contract assets recognized | 0.0 |  | 0.0 |
Thacker Pass |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Advance paid | 3.5 |  | 3.5 |
Cost reimbursement, commercial mining milestone, fee | $ 4.7 |  | $ 4.7 |
Minimum |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Primary term of contract |  |  | 3 years |
Maximum |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Primary term of contract |  |  | 5 years |

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