Investments - Net Unrealized Gains (Losses) on Investments (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
|
| Marketable Securities [Line Items] | ||||
| Unrealized gain (loss) on investments | $ 41,804 | $ 5,781 | $ 32,986 | $ 147,822 |
| Fixed maturities and short-term investments | ||||
| Marketable Securities [Line Items] | ||||
| Unrealized gain (loss) on investments | (90,312) | 7,227 | (137,483) | 70,496 |
| TS Hamilton Fund | ||||
| Marketable Securities [Line Items] | ||||
| Unrealized gain (loss) on investments | $ 132,116 | $ (1,446) | $ 170,469 | $ 77,326 |