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Fair Value of Financial Instruments - Narrative (Details) - USD ($) $ in Millions | Sep. 30, 2025 | May 29, 2025 | Feb. 12, 2025 | Dec. 31, 2024
--- | --- | --- | --- | ---
BVES |  |  |  |
Fair value of financial instruments |  |  |  |
Face amount of debt |  |  | $ 50.0 |
Unsecured private-placement notes | GSWC |  |  |  |
Fair value of financial instruments |  |  |  |
Face amount of debt | $ 100.0 | $ 100.0 |  |
Unsecured private-placement notes | BVES |  |  |  |
Fair value of financial instruments |  |  |  |
Face amount of debt | 50.0 |  |  |
Mutual Funds | Fair Value, Inputs, Level 1 |  |  |  |
Fair value of financial instruments |  |  |  |
Other Investments and Securities, at Cost | $ 45.8 |  |  | $ 41.2

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