Reinsurance Reinsurance (Effect Of Reinsurance And Retrocessional Reinsurance On Losses) (Details) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2025 |
Mar. 31, 2024 |
|
| Effects of Reinsurance [Line Items] | ||
| Net losses and loss adjustment expenses | $ 1,254,665 | $ 1,287,747 |
| Underwriting [Member] | ||
| Effects of Reinsurance [Line Items] | ||
| Gross losses and loss adjustment expenses | 1,673,509 | 1,693,847 |
| Ceded losses and loss adjustment expenses | (418,927) | (406,167) |
| Net losses and loss adjustment expenses | $ 1,254,582 | $ 1,287,680 |