v3.26.1
Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale $ 2,192,183 $ 1,856,303
Total fixed maturity securities, held-to-maturity 34,716 33,603
Total equity securities 1,141 1,174
Mortgage loans 9,218 9,902
Short-term investments 392,634 264,299
Derivatives 40,535 34,857
Total 2,670,427 2,200,138
U.S. government securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 127,064 44,468
Non U.S government securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 2,677  
Corporate securities and miscellaneous    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 790,807 636,387
Municipal securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 92,213 102,116
Residential mortgage-backed securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 445,211 486,587
Commercial mortgage-backed securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 84,624 73,050
Other asset-backed securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 649,587 513,695
Total fixed maturity securities, held-to-maturity 34,716 33,603
Preferred stocks    
Fixed maturity securities, available-for-sale:    
Total equity securities 1,141 1,174
Level 1    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 127,064 44,468
Total fixed maturity securities, held-to-maturity 0 0
Total equity securities 0 0
Mortgage loans 0 0
Short-term investments 392,634 264,299
Derivatives 40,535 34,857
Total 560,233 343,624
Level 1 | U.S. government securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 127,064 44,468
Level 1 | Non U.S government securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 0  
Level 1 | Corporate securities and miscellaneous    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 0 0
Level 1 | Municipal securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 0 0
Level 1 | Residential mortgage-backed securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 0 0
Level 1 | Commercial mortgage-backed securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 0 0
Level 1 | Other asset-backed securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 0 0
Total fixed maturity securities, held-to-maturity 0 0
Level 1 | Preferred stocks    
Fixed maturity securities, available-for-sale:    
Total equity securities 0 0
Level 2    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 1,907,296 1,660,918
Total fixed maturity securities, held-to-maturity 0 0
Total equity securities 1,141 1,174
Mortgage loans 0 0
Short-term investments 0 0
Derivatives 0 0
Total 1,908,437 1,662,092
Level 2 | U.S. government securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 0 0
Level 2 | Non U.S government securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 2,677  
Level 2 | Corporate securities and miscellaneous    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 650,362 503,274
Level 2 | Municipal securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 92,213 102,116
Level 2 | Residential mortgage-backed securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 445,211 486,587
Level 2 | Commercial mortgage-backed securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 84,624 73,050
Level 2 | Other asset-backed securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 632,209 495,891
Total fixed maturity securities, held-to-maturity 0 0
Level 2 | Preferred stocks    
Fixed maturity securities, available-for-sale:    
Total equity securities 1,141 1,174
Level 3    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 157,823 150,917
Total fixed maturity securities, held-to-maturity 34,716 33,603
Total equity securities 0 0
Mortgage loans 9,218 9,902
Short-term investments 0 0
Derivatives 0 0
Total 201,757 194,422
Level 3 | U.S. government securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 0 0
Level 3 | Non U.S government securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 0  
Level 3 | Corporate securities and miscellaneous    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 140,445 133,113
Level 3 | Municipal securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 0 0
Level 3 | Residential mortgage-backed securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 0 0
Level 3 | Commercial mortgage-backed securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 0 0
Level 3 | Other asset-backed securities    
Fixed maturity securities, available-for-sale:    
Total fixed maturity securities, available-for-sale 17,378 17,804
Total fixed maturity securities, held-to-maturity 34,716 33,603
Level 3 | Preferred stocks    
Fixed maturity securities, available-for-sale:    
Total equity securities $ 0 $ 0