Investment Securities - Investments In Private Equity Funds Subject to Lock-Up Periods (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2025 |
Dec. 31, 2024 |
|
| Debt and Equity Securities, FV-NI [Line Items] | ||
| 1 – 3 years | $ 14.6 | |
| 3 – 5 years | 51.5 | |
| 5 – 10 years | 149.6 | |
| >10 years | 24.9 | |
| Total | 2,287.9 | $ 2,150.2 |
| Private equity funds | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Total | $ 240.6 | |
| Hedge funds | Minimum | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Notice period | 45 days | |
| Hedge funds | Maximum | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Notice period | 90 days | |
| ILS funds | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Total | $ 71.3 | 74.0 |
| ILS funds | Minimum | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Notice period | 30 days | |
| ILS funds | Maximum | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Notice period | 90 days | |
| Bank loan fund | ||
| Debt and Equity Securities, FV-NI [Line Items] | ||
| Total | $ 264.9 | $ 264.7 |