v3.26.3
Segment Reporting - Schedule of Segment Reporting Information (Details)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2026
USD ($)
Sep. 30, 2025
USD ($)
Sep. 30, 2026
USD ($)
segment
Sep. 30, 2025
USD ($)
Segment Reporting [Line Items]        
Number of reportable segments | segment     2  
Gross premiums written $ 819,702 $ 698,845 $ 2,590,854 $ 2,254,177
Net premiums written 626,722 578,981 1,902,077 1,739,169
Net premiums earned 591,274 522,999 1,747,797 1,533,090
Third party fee income 2,812 4,169 13,466 13,845
Losses and loss adjustment expenses 366,726 278,712 1,053,000 943,875
Acquisition costs 150,972 125,412 440,902 365,108
Other underwriting expenses 60,861 58,955 165,140 164,664
Underwriting income (loss) 15,527 64,089 102,221 73,288
Net realized and unrealized gains (losses) on investments 208,526 115,136 587,458 571,964
Net investment income (loss) 26,615 22,727 77,084 62,721
Net foreign exchange gains (losses) (1,188) 2,619 719 (4,422)
Corporate expenses (14,097) (15,347) (38,213) (41,168)
Amortization of intangible assets (3,762) (4,000) (11,482) (11,895)
Interest expense (4,801) (4,933) (14,339) (15,264)
Income (loss) before income tax 226,820 180,291 703,448 635,224
Income tax (expense) benefit 1,363 (3,866) (3,430) (9,748)
Net income (loss) 228,183 176,425 700,018 625,476
Net income (loss) attributable to non-controlling interest 146,727 40,225 341,242 220,990
Net income (loss) and other comprehensive income (loss) attributable to common shareholders $ 81,456 $ 136,200 $ 358,776 $ 404,486
Attritional loss ratio - current year 57.50% 55.40% 55.10% 53.40%
Attritional loss ratio - prior year development (4.60%) (2.10%) (0.80%) (1.80%)
Catastrophe loss ratio - current year 1.10% 0.00% 3.00% 11.10%
Catastrophe loss ratio - prior year development 8.00% 0.00% 2.90% (1.10%)
Loss and loss adjustment expense ratio 62.00% 53.30% 60.20% 61.60%
Acquisition cost ratio 25.50% 24.00% 25.20% 23.80%
Other underwriting expense ratio 9.80% 10.50% 8.70% 9.80%
Combined ratio 97.30% 87.80% 94.10% 95.20%
Operating Segments | International        
Segment Reporting [Line Items]        
Gross premiums written $ 456,332 $ 379,957 $ 1,319,314 $ 1,094,715
Net premiums written 349,250 304,410 959,530 791,473
Net premiums earned 309,313 252,302 902,728 746,078
Third party fee income 1,618 2,137 5,985 10,301
Losses and loss adjustment expenses 169,916 133,895 508,045 404,300
Acquisition costs 85,920 67,007 247,411 195,480
Other underwriting expenses 46,136 41,703 128,193 116,833
Underwriting income (loss) $ 8,959 $ 11,834 $ 25,064 $ 39,766
Attritional loss ratio - current year 54.50% 55.30% 53.50% 53.10%
Attritional loss ratio - prior year development (3.20%) (2.20%) (2.20%) (2.90%)
Catastrophe loss ratio - current year 2.20% 0.00% 4.50% 4.10%
Catastrophe loss ratio - prior year development 1.40% 0.00% 0.50% (0.10%)
Loss and loss adjustment expense ratio 54.90% 53.10% 56.30% 54.20%
Acquisition cost ratio 27.80% 26.60% 27.40% 26.20%
Other underwriting expense ratio 14.40% 15.70% 13.50% 14.30%
Combined ratio 97.10% 95.40% 97.20% 94.70%
Operating Segments | Bermuda        
Segment Reporting [Line Items]        
Gross premiums written $ 363,370 $ 318,888 $ 1,271,540 $ 1,159,462
Net premiums written 277,472 274,571 942,547 947,696
Net premiums earned 281,961 270,697 845,069 787,012
Third party fee income 1,194 2,032 7,481 3,544
Losses and loss adjustment expenses 196,810 144,817 544,955 539,575
Acquisition costs 65,052 58,405 193,491 169,628
Other underwriting expenses 14,725 17,252 36,947 47,831
Underwriting income (loss) $ 6,568 $ 52,255 $ 77,157 $ 33,522
Attritional loss ratio - current year 60.80% 55.60% 56.90% 53.90%
Attritional loss ratio - prior year development (6.10%) (2.10%) 0.70% (0.80%)
Catastrophe loss ratio - current year 0.00% 0.00% 1.40% 17.70%
Catastrophe loss ratio - prior year development 15.10% 0.00% 5.50% (2.20%)
Loss and loss adjustment expense ratio 69.80% 53.50% 64.50% 68.60%
Acquisition cost ratio 23.10% 21.60% 22.90% 21.60%
Other underwriting expense ratio 4.80% 5.60% 3.50% 5.60%
Combined ratio 97.70% 80.70% 90.90% 95.80%
Corporate        
Segment Reporting [Line Items]        
Gross premiums written $ 0 $ 0 $ 0 $ 0
Net premiums written 0 0 0 0
Net premiums earned 0 0 0 0
Third party fee income 0 0 0 0
Losses and loss adjustment expenses 0 0 0 0
Acquisition costs 0 0 0 0
Other underwriting expenses 0 0 0 0
Underwriting income (loss) 0 0 0 0
Net realized and unrealized gains (losses) on investments 208,526 115,136 587,458 571,964
Net investment income (loss) 26,615 22,727 77,084 62,721
Net foreign exchange gains (losses) (1,188) 2,619 719 (4,422)
Corporate expenses (14,097) (15,347) (38,213) (41,168)
Amortization of intangible assets (3,762) (4,000) (11,482) (11,895)
Interest expense (4,801) (4,933) (14,339) (15,264)
Income tax (expense) benefit 1,363 (3,866) (3,430) (9,748)
Net income (loss) attributable to non-controlling interest $ 146,727 $ 40,225 $ 341,242 $ 220,990