v3.26.1
Segment Information - Summary of Operating Results by Segment (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Segment Reporting [Line Items]    
Net premiums earned $ 1,452,413 $ 1,283,069
Total incurred losses and loss adjustment expenses 932,950 1,220,813
Policy acquisition costs 240,502 228,720
Other operating expenses 123,887 79,453
Net investment income 85,636 81,479
Net realized investment (losses) gains (4,543) 23,321
Other income 6,303 6,010
Interest expense (6,817) (7,189)
Income (loss) before income taxes 235,653 (142,296)
Net income (loss) 190,421 (108,327)
Operating Segments    
Segment Reporting [Line Items]    
Net premiums earned 1,452,400 1,283,100
Losses 796,700 1,069,300
Loss adjustment expenses 136,200 151,500
Total incurred losses and loss adjustment expenses 932,900 1,220,800
Policy acquisition costs 240,500 228,700
Other operating expenses 123,900 79,500
Underwriting gain (loss) 155,100 (245,900)
Net investment income 85,600 81,500
Net realized investment (losses) gains (4,500) 23,300
Other income 6,300 6,000
Interest expense (6,800) (7,200)
Income (loss) before income taxes 235,700 (142,300)
Net income (loss) 190,400 (108,300)
Property & Casualty    
Segment Reporting [Line Items]    
Net premiums earned 1,445,096 1,275,758
Property & Casualty | Operating Segments    
Segment Reporting [Line Items]    
Net premiums earned 1,445,100 1,275,800
Losses 792,700 1,065,600
Loss adjustment expenses 135,700 151,000
Total incurred losses and loss adjustment expenses 928,400 1,216,600
Policy acquisition costs 237,800 225,800
Other operating expenses 123,100 78,900
Underwriting gain (loss) 155,800 (245,500)
Other | Operating Segments    
Segment Reporting [Line Items]    
Net premiums earned 7,300 7,300
Losses 4,000 3,700
Loss adjustment expenses 500 500
Total incurred losses and loss adjustment expenses 4,500 4,200
Policy acquisition costs 2,700 2,900
Other operating expenses 800 600
Underwriting gain (loss) $ (700) $ (400)