XML 120 R82.htm IDEA: XBRL DOCUMENT v3.24.1
Reserves for Losses and Adjustment Expenses - Reconciliation of Reinsurance Recoverables on Unpaid Losses (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
May 30, 2022
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]      
Reinsurance recoverable for unpaid claims under retroactive reinsurance, beginning balance $ 4,897.7    
Reinsurance recoverable for unpaid claims under retroactive reinsurance, beginning balance, Ending Balance 4,577.8 $ 4,897.7  
Provision for losses and LAE for claims incurred 60.8 28.1  
Reinsurance Contracts [Axis]: LPT      
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]      
Reinsurance recoverables, premium paid and recognized     $ 1,840.1
Reinsurance Contracts [Axis]: Retroactive Reinsurance      
SEC Schedule, 12-17, Insurance Companies, Reinsurance [Line Items]      
Reinsurance recoverable for unpaid claims under retroactive reinsurance, beginning balance 2,132.0    
Reinsurance recoverable for unpaid claims under retroactive reinsurance, beginning balance, Ending Balance $ 1,627.4 $ 2,132.0