v3.26.1
Comprehensive Income (Loss) - Schedule of Reclassification out of AOCI (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]        
Net realized and unrealized investment gains (losses) $ 11,971 $ 4,172 $ 3,670 $ 4,401
Loss and loss expense incurred 816,266 823,898 1,631,770 1,570,223
Other insurance expenses 136,192 122,823 270,876 247,693
Income (loss) before income tax 162,845 108,905 287,047 247,791
Total income tax expense (benefit) (33,460) (22,962) (59,986) (51,952)
Net income (loss) 129,385 85,943 227,061 195,839
Reclassification out of AOCI        
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]        
Net income (loss) 4,251 (355) 12,642 (379)
Reclassification out of AOCI | Net realized (gains) losses on disposals and intent-to-sell AFS securities        
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]        
Net realized and unrealized investment gains (losses) 3,318 (434) 4,981 (708)
Total income tax expense (benefit) (696) 91 (1,046) 149
Net income (loss) 2,622 (343) 3,935 (559)
Reclassification out of AOCI | Credit loss related        
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]        
Net realized and unrealized investment gains (losses) 1,255 (887) 9,409 (1,516)
Total income tax expense (benefit) (263) 186 (1,976) 318
Net income (loss) 992 (701) 7,433 (1,198)
Reclassification out of AOCI | Defined benefit pension and post-retirement life plans        
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]        
Loss and loss expense incurred 185 200 371 401
Other insurance expenses 621 673 1,242 1,344
Income (loss) before income tax 806 873 1,613 1,745
Total income tax expense (benefit) (169) (184) (339) (367)
Net income (loss) $ 637 $ 689 $ 1,274 $ 1,378