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Fair Value Measurements - Narrative (Details) - USD ($) | 3 Months Ended | 6 Months Ended |  |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 30, 2026 | Jun. 30, 2025 | Jun. 30, 2026 | Jun. 30, 2025 | Jan. 31, 2026 | Dec. 31, 2025 | Dec. 31, 2024 | Sep. 30, 2024 | Mar. 31, 2024 | Oct. 31, 2021 | Mar. 31, 2021 | Apr. 30, 2019
Fair Value Measurements |  |  |  |  |  |  |  |  |  |  |  |
Contribution to decommissioning trust fund |  |  | $ 11,600,000 | $ 11,500,000 |  |  |  |  |  |  |  |
Impairment of long-lived assets | $ 0 | $ 0 | $ 0 | $ 0 |  |  |  |  |  |  |  |
7.125% Senior Notes | Senior Notes |  |  |  |  |  |  |  |  |  |  |  |
Fair Value Measurements |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  |  | 7.125%
7.750% Senior Notes | Senior Notes |  |  |  |  |  |  |  |  |  |  |  |
Fair Value Measurements |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  |  |  | 7.75% |  |
7.500% Senior Notes | Senior Notes |  |  |  |  |  |  |  |  |  |  |  |
Fair Value Measurements |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  |  |  |  | 7.50% |
8.750% Senior Notes | Senior Notes |  |  |  |  |  |  |  |  |  |  |  |
Fair Value Measurements |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  |  |  |  | 8.75% |  |  |  |
3.125% Convertible Senior Notes | Senior Notes |  |  |  |  |  |  |  |  |  |  |  |
Fair Value Measurements |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) | 3.125% |  | 3.125% |  |  | 3.125% | 3.125% |  | 3.125% |  |  |
11.250% Senior Secured Bonds | Senior Secured Bond |  |  |  |  |  |  |  |  |  |  |  |
Fair Value Measurements |  |  |  |  |  |  |  |  |  |  |  |
Interest rate (as a percent) |  |  |  |  | 11.25% |  |  |  |  |  |  |

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