v3.26.1
Investments - Schedule of Debt Securities, Trading, and Equity Securities, FV-NI (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Mar. 31, 2025
Dec. 31, 2024
Fixed maturity securities, available-for-sale:        
Amortized Cost $ 2,208,212 $ 1,848,755    
Gross Unrealized Gains 19,503 31,378    
Gross Unrealized Losses (26,108) (16,830)    
Allowance for Credit Losses (6,500) (7,000)    
Fair Value 2,195,107 1,856,303    
Fixed maturity securities, held-to-maturity:        
Amortized Cost 30,395 33,290    
Gross Unrealized Gains 4,196 829    
Gross Unrealized Losses 0 (48)    
Allowance for Credit Losses (301) (468) $ (250) $ (243)
Fair Value 34,290 33,603    
U.S. government securities        
Fixed maturity securities, available-for-sale:        
Amortized Cost 160,144 44,190    
Gross Unrealized Gains 178 292    
Gross Unrealized Losses (774) (14)    
Allowance for Credit Losses 0 0    
Fair Value 159,548 44,468    
Non U.S government securities        
Fixed maturity securities, available-for-sale:        
Amortized Cost 2,696      
Gross Unrealized Gains 0      
Gross Unrealized Losses (25)      
Allowance for Credit Losses 0      
Fair Value 2,671      
Corporate securities and miscellaneous        
Fixed maturity securities, available-for-sale:        
Amortized Cost 807,859 632,244    
Gross Unrealized Gains 8,007 14,223    
Gross Unrealized Losses (8,881) (3,080)    
Allowance for Credit Losses (6,500) (7,000)    
Fair Value 800,485 636,387    
Municipal securities        
Fixed maturity securities, available-for-sale:        
Amortized Cost 96,647 102,691    
Gross Unrealized Gains 1,150 1,725    
Gross Unrealized Losses (2,168) (2,300)    
Allowance for Credit Losses 0 0    
Fair Value 95,629 102,116    
Residential mortgage-backed securities        
Fixed maturity securities, available-for-sale:        
Amortized Cost 475,069 487,145    
Gross Unrealized Gains 6,260 8,928    
Gross Unrealized Losses (10,154) (9,486)    
Allowance for Credit Losses 0 0    
Fair Value 471,175 486,587    
Commercial mortgage-backed securities        
Fixed maturity securities, available-for-sale:        
Amortized Cost 79,618 72,631    
Gross Unrealized Gains 669 1,016    
Gross Unrealized Losses (615) (597)    
Allowance for Credit Losses 0 0    
Fair Value 79,672 73,050    
Other asset-backed securities        
Fixed maturity securities, available-for-sale:        
Amortized Cost 586,179 509,854    
Gross Unrealized Gains 3,239 5,194    
Gross Unrealized Losses (3,491) (1,353)    
Allowance for Credit Losses 0 0    
Fair Value 585,927 513,695    
Fixed maturity securities, held-to-maturity:        
Amortized Cost 30,395 33,290    
Gross Unrealized Gains 4,196 829    
Gross Unrealized Losses 0 (48)    
Allowance for Credit Losses (301) (468)    
Fair Value $ 34,290 $ 33,603