v3.26.1
Investments - Securities In Unrealized Loss Position (Details)
$ in Thousands
Jun. 30, 2026
USD ($)
security
Dec. 31, 2025
USD ($)
security
Schedule of Investments [Line Items]    
Less Than 12 Months - Fair Value $ 1,550,757 $ 521,574
12 Months or Greater - Fair Value 2,032,890 2,324,283
Total - Fair Value 3,583,647 2,845,857
Less Than 12 Months - Unrealized Losses (13,539) (8,528)
12 Months or Greater - Unrealized Losses (216,673) (206,139)
Total - Unrealized Losses $ (230,212) $ (214,667)
Number of securities in unrealized loss position (in securities) | security 996 712
U.S. Treasury securities and obligations of U.S. government corporations and agencies    
Schedule of Investments [Line Items]    
Less Than 12 Months - Fair Value $ 160,992 $ 15,762
12 Months or Greater - Fair Value 30,819 51,113
Total - Fair Value 191,811 66,875
Less Than 12 Months - Unrealized Losses (744) (60)
12 Months or Greater - Unrealized Losses (2,302) (2,445)
Total - Unrealized Losses (3,046) (2,505)
Obligations of U.S. states and political subdivisions    
Schedule of Investments [Line Items]    
Less Than 12 Months - Fair Value 200,110 144,148
12 Months or Greater - Fair Value 1,030,622 1,087,931
Total - Fair Value 1,230,732 1,232,079
Less Than 12 Months - Unrealized Losses (3,037) (6,123)
12 Months or Greater - Unrealized Losses (136,044) (127,912)
Total - Unrealized Losses (139,081) (134,035)
Corporate debt securities    
Schedule of Investments [Line Items]    
Less Than 12 Months - Fair Value 810,234 258,349
12 Months or Greater - Fair Value 761,003 887,659
Total - Fair Value 1,571,237 1,146,008
Less Than 12 Months - Unrealized Losses (6,333) (1,180)
12 Months or Greater - Unrealized Losses (58,689) (56,677)
Total - Unrealized Losses (65,022) (57,857)
ABS    
Schedule of Investments [Line Items]    
Less Than 12 Months - Fair Value 172,169 49,774
12 Months or Greater - Fair Value 4,584 22,965
Total - Fair Value 176,753 72,739
Less Than 12 Months - Unrealized Losses (1,575) (1,103)
12 Months or Greater - Unrealized Losses (1,238) (232)
Total - Unrealized Losses (2,813) (1,335)
RMBS    
Schedule of Investments [Line Items]    
Less Than 12 Months - Fair Value 51,103 2,906
12 Months or Greater - Fair Value 150,115 187,553
Total - Fair Value 201,218 190,459
Less Than 12 Months - Unrealized Losses (351) (8)
12 Months or Greater - Unrealized Losses (16,407) (16,808)
Total - Unrealized Losses (16,758) (16,816)
CMBS    
Schedule of Investments [Line Items]    
Less Than 12 Months - Fair Value 120,580 15,363
12 Months or Greater - Fair Value 51,690 82,994
Total - Fair Value 172,270 98,357
Less Than 12 Months - Unrealized Losses (1,446) (30)
12 Months or Greater - Unrealized Losses (1,562) (1,645)
Total - Unrealized Losses (3,008) (1,675)
CLOs    
Schedule of Investments [Line Items]    
Less Than 12 Months - Fair Value 32,231 35,272
12 Months or Greater - Fair Value 0 0
Total - Fair Value 32,231 35,272
Less Than 12 Months - Unrealized Losses (52) (24)
12 Months or Greater - Unrealized Losses 0 0
Total - Unrealized Losses (52) (24)
Foreign government debt    
Schedule of Investments [Line Items]    
Less Than 12 Months - Fair Value 0 0
12 Months or Greater - Fair Value 4,057 4,068
Total - Fair Value 4,057 4,068
Less Than 12 Months - Unrealized Losses 0 0
12 Months or Greater - Unrealized Losses (431) (420)
Total - Unrealized Losses (431) $ (420)
Commercial paper    
Schedule of Investments [Line Items]    
Less Than 12 Months - Fair Value 3,338  
12 Months or Greater - Fair Value 0  
Total - Fair Value 3,338  
Less Than 12 Months - Unrealized Losses (1)  
12 Months or Greater - Unrealized Losses 0  
Total - Unrealized Losses $ (1)