v3.22.2.2
Reinsurance - Current Ratings from Rating Agencies and Unsecured Net Amounts Due from Reinsurers Whose Aggregate Balance Exceeded 3% of Stockholders' Equity (Detail) - USD ($)
$ in Thousands
Sep. 30, 2022
Dec. 31, 2021
Ceded Credit Risk [Line Items]    
Reinsurance unsecured amounts due from reinsurers $ 823,105 $ 200,967
Allianz Risk Transfer | AM Best Company A Plus Rating | Standard & Poor's, AA- Rating | Moody's, Aa3 Rating    
Ceded Credit Risk [Line Items]    
Reinsurance unsecured amounts due from reinsurers 371,290 0
Various Lloyd’s of London Syndicates | AM Best, A Rating | Standard & Poor's, A Plus Rating    
Ceded Credit Risk [Line Items]    
Reinsurance unsecured amounts due from reinsurers 132,967 0
Chubb Tempest Reinsurance, Ltd. | AM Best, A++ Rating | Standard & Poor's, AA Rating | Moody's, Aa3 Rating    
Ceded Credit Risk [Line Items]    
Reinsurance unsecured amounts due from reinsurers 62,592 0
Florida Hurricane Catastrophe Fund    
Ceded Credit Risk [Line Items]    
Reinsurance unsecured amounts due from reinsurers 61,024 136,298
DaVinci Reinsurance Ltd. | AM Best, A Rating | Standard & Poor's, AA- Rating | Moody's, A3 Rating    
Ceded Credit Risk [Line Items]    
Reinsurance unsecured amounts due from reinsurers 58,290 0
Renaissance Reinsurance Ltd. | AM Best Company A Plus Rating | Standard & Poor's, A Plus Rating | Moody's A1 Rating    
Ceded Credit Risk [Line Items]    
Reinsurance unsecured amounts due from reinsurers 49,773 20,051
Markel Bermuda Ltd. | AM Best, A Rating | Standard & Poor's, A Rating | Moody's, A2 Rating    
Ceded Credit Risk [Line Items]    
Reinsurance unsecured amounts due from reinsurers 46,770 0
Munich Reinsurance America Inc. | AM Best Company A Plus Rating | Standard & Poor's, AA- Rating | Moody's, Aa3 Rating    
Ceded Credit Risk [Line Items]    
Reinsurance unsecured amounts due from reinsurers 19,122 0
Everest Reinsurance Co | AM Best Company A Plus Rating | Standard & Poor's, A Plus Rating | Moody's A1 Rating    
Ceded Credit Risk [Line Items]    
Reinsurance unsecured amounts due from reinsurers 11,994 0
Lumen Re Ltd. | AM Best, A Rating    
Ceded Credit Risk [Line Items]    
Reinsurance unsecured amounts due from reinsurers 9,283 0
Allianz Risk Transfer (Bermuda) Ltd.    
Ceded Credit Risk [Line Items]    
Reinsurance unsecured amounts due from reinsurers $ 0 $ 44,618