Fair Value Measurement - Gains (Losses) on Securities (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Fair Value Disclosures [Abstract] | ||||
| Change in unrealized investment gains (losses) during the year on securities held at the end of the period | $ 4,640 | $ (28,916) | $ (2,383) | $ 2,253 |
| Investment gains (losses) during the period on securities sold | 0 | 0 | 0 | 0 |
| Net gains (losses) recognized on equity securities | $ 4,640 | $ (28,916) | $ (2,383) | $ 2,253 |