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v3.24.3

Segment Information - Schedule of Revenue by Segment (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | $ 1,112,228 | $ 981,917 | $ 3,243,403 | $ 2,826,403
Miscellaneous income | 8,930 | 5,181 | 22,566 | 13,919
Net investment income earned | 117,759 | 100,863 | 334,250 | 290,065
Net realized and unrealized investment gains (losses) | 5,389 | (6,880) | 5,051 | (8,962)
Total Investments revenue | 123,148 | 93,983 | 339,301 | 281,103
Total revenues | 1,244,306 | 1,081,081 | 3,605,270 | 3,121,425
Standard Commercial Lines |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Total revenues | 883,568 | 789,934 | 2,583,519 | 2,292,007
Standard Commercial Lines | General liability |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | 286,641 | 261,551 | 840,153 | 759,410
Standard Commercial Lines | Commercial automobile |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | 269,036 | 234,622 | 781,408 | 677,060
Standard Commercial Lines | Commercial property |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | 174,855 | 152,495 | 504,919 | 429,135
Standard Commercial Lines | Workers compensation |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | 81,296 | 81,672 | 251,389 | 254,602
Standard Commercial Lines | Businessowners' policies |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | 43,091 | 36,016 | 124,653 | 103,572
Standard Commercial Lines | Bonds |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | 12,511 | 11,715 | 37,067 | 34,731
Standard Commercial Lines | Other |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | 7,949 | 7,257 | 23,393 | 21,142
Standard Commercial Lines | Miscellaneous income |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Miscellaneous income | 8,189 | 4,606 | 20,537 | 12,355
Standard Personal Lines |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Total revenues | 108,213 | 95,744 | 319,715 | 265,773
Standard Personal Lines | Miscellaneous income |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Miscellaneous income | 692 | 575 | 1,927 | 1,564
Standard Personal Lines | Personal automobile |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | 56,599 | 51,906 | 171,103 | 145,050
Standard Personal Lines | Homeowners |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | 47,251 | 40,175 | 137,419 | 112,090
Standard Personal Lines | Other |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | 3,671 | 3,088 | 9,266 | 7,069
E&S Lines |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Total revenues | 129,377 | 101,420 | 362,735 | 282,542
E&S Lines | Miscellaneous income |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Miscellaneous income | 49 | 0 | 102 | 0
E&S Lines | Casualty lines |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | 77,471 | 67,718 | 222,996 | 190,686
E&S Lines | Property lines |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net premiums earned: | $ 51,857 | $ 33,702 | $ 139,637 | $ 91,856

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