XML 205 R154.htm IDEA: XBRL DOCUMENT v3.24.3
Schedule IV - Reinsurance Premiums Written and Premiums Earned (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2024
Sep. 30, 2023
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Abstract]              
Direct         $ 2,446.6 $ 2,531.7 $ 2,341.4
Assumed         1,521.0 1,807.0 1,597.0
Ceded $ (443.2) $ (354.1) $ (1,373.0) $ (1,128.8) (1,385.7) (1,442.7) (1,350.7)
Net written premiums 673.6 628.6 2,225.6 1,979.1 2,581.9 2,896.0 2,587.7
Gross Amount         2,444.8 2,370.8 2,139.1
Assumed From Other Companies         1,562.0 1,617.2 1,479.2
Ceded (403.9) (361.2) (1,105.0) (1,033.1) (1,392.3) (1,299.3) (1,207.8)
Net premiums earned 698.3 660.0 2,069.4 1,947.4 $ 2,614.5 $ 2,688.7 $ 2,410.5
Percentage of Amount Assumed to Net         59.70% 60.10% 61.40%
Gross written premiums $ 1,116.8 $ 982.7 $ 3,598.6 $ 3,107.9 $ 3,967.6 $ 4,338.7 $ 3,938.4