XML 76 R59.htm IDEA: XBRL DOCUMENT v3.25.0.1
Investments - Schedule of Realized Gain and Loss and Investments in Unrealized Loss Position (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]      
Realized gross gains $ 495 $ 1,219 $ 14,420
Realized gross losses 2,322 8,246 14,864
Impairment loss 523 177 $ 12,728
Fair Value      
Less than 12 months 1,954,295 550,525  
12 months or more 2,567,865 3,200,767  
Total 4,522,160 3,751,292  
Gross Unrealized Losses      
Less than 12 months (50,014) (5,759)  
12 months or more (308,438) (330,678)  
Total (358,452) (336,437)  
U.S. Treasury securities      
Fair Value      
Less than 12 months 141,789 139,398  
12 months or more 279,143 355,921  
Total 420,932 495,319  
Gross Unrealized Losses      
Less than 12 months (1,620) (1,075)  
12 months or more (13,268) (18,053)  
Total (14,888) (19,128)  
U.S. agency securities      
Fair Value      
Less than 12 months   5,572  
12 months or more   1,623  
Total   7,195  
Gross Unrealized Losses      
Less than 12 months   (2)  
12 months or more   (2)  
Total   (4)  
U.S. agency mortgage-backed securities      
Fair Value      
Less than 12 months 476,695 129,359  
12 months or more 629,036 654,018  
Total 1,105,731 783,377  
Gross Unrealized Losses      
Less than 12 months (13,028) (1,616)  
12 months or more (110,837) (100,383)  
Total (123,865) (101,999)  
Municipal debt securities      
Fair Value      
Less than 12 months 204,810 59,301  
12 months or more 282,312 297,039  
Total 487,122 356,340  
Gross Unrealized Losses      
Less than 12 months (5,688) (987)  
12 months or more (43,422) (43,462)  
Total (49,110) (44,449)  
Non-U.S. government securities      
Fair Value      
Less than 12 months 4,146 0  
12 months or more 65,652 67,447  
Total 69,798 67,447  
Gross Unrealized Losses      
Less than 12 months (262) 0  
12 months or more (11,571) (10,069)  
Total (11,833) (10,069)  
Corporate debt securities      
Fair Value      
Less than 12 months 898,449 119,764  
12 months or more 725,148 905,606  
Total 1,623,597 1,025,370  
Gross Unrealized Losses      
Less than 12 months (25,547) (733)  
12 months or more (80,118) (87,170)  
Total (105,665) (87,903)  
Residential and commercial mortgage securities      
Fair Value      
Less than 12 months 39,931 31,936  
12 months or more 421,891 459,789  
Total 461,822 491,725  
Gross Unrealized Losses      
Less than 12 months (1,168) (999)  
12 months or more (40,886) (52,510)  
Total (42,054) (53,509)  
Asset-backed securities      
Fair Value      
Less than 12 months 188,475 65,195  
12 months or more 164,683 459,324  
Total 353,158 524,519  
Gross Unrealized Losses      
Less than 12 months (2,701) (347)  
12 months or more (8,336) (19,029)  
Total $ (11,037) $ (19,376)