Fair Value Measurements - Schedule of Investments in Debt Securities Held by Decommissioning Trust Fund (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
|
| Fair Value Measurements | ||||
| Purchases | $ 448 | $ 245 | $ 12,499 | $ 12,651 |
| Net Proceeds | 118 | (20) | 64 | (599) |
| Unrealized Gain (Loss) | (170) | 43 | (276) | 174 |
| Debt securities held in decommissioning trust fund | ||||
| Fair Value Measurements | ||||
| Purchases | 448 | 245 | 12,499 | 12,651 |
| Net Proceeds | 0 | 0 | 0 | 0 |
| Unrealized Gain (Loss) | (170) | 43 | (276) | 174 |
| Cash and cash equivalents | ||||
| Fair Value Measurements | ||||
| Purchases | 0 | 0 | 0 | 0 |
| Net Proceeds | 0 | (3) | 1 | (748) |
| Unrealized Gain (Loss) | 0 | 0 | 0 | 0 |
| Other | ||||
| Fair Value Measurements | ||||
| Purchases | 0 | 0 | 0 | 0 |
| Net Proceeds | 118 | (17) | 63 | 149 |
| Unrealized Gain (Loss) | $ 0 | $ 0 | $ 0 | $ 0 |