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v3.23.1

Segment Information (Revenue by Segment) (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2023 | Mar. 31, 2022
Segment Reporting Information [Line Items] |  |
Net premiums earned | $ 902,336 | $ 812,283
Other income | 2,634 | 1,529
Net investment income earned | 91,506 | 72,602
Net realized and unrealized investment gains (losses) | 3,344 | (40,352)
Total Investments revenue | 94,850 | 32,250
Total revenues | 999,820 | 846,062
Standard Commercial Lines |  |
Segment Reporting Information [Line Items] |  |
Total revenues | 733,796 | 662,570
Standard Commercial Lines | General Liability [Member] |  |
Segment Reporting Information [Line Items] |  |
Net premiums earned | 243,349 | 216,325
Standard Commercial Lines | Commercial Automobile [Member] |  |
Segment Reporting Information [Line Items] |  |
Net premiums earned | 217,371 | 193,830
Standard Commercial Lines | Commercial Property [Member] |  |
Segment Reporting Information [Line Items] |  |
Net premiums earned | 135,292 | 120,062
Standard Commercial Lines | Workers Compensation [Member] |  |
Segment Reporting Information [Line Items] |  |
Net premiums earned | 84,184 | 84,680
Standard Commercial Lines | Business Owners Policies [Member] |  |
Segment Reporting Information [Line Items] |  |
Net premiums earned | 33,171 | 30,044
Standard Commercial Lines | Bonds Segment [Member] |  |
Segment Reporting Information [Line Items] |  |
Net premiums earned | 11,397 | 10,360
Standard Commercial Lines | Other Commercial [Member] |  |
Segment Reporting Information [Line Items] |  |
Net premiums earned | 6,851 | 6,168
Standard Commercial Lines | Miscellaneous income |  |
Segment Reporting Information [Line Items] |  |
Other income | 2,181 | 1,101
Standard Personal Lines |  |
Segment Reporting Information [Line Items] |  |
Total revenues | 82,323 | 73,070
Standard Personal Lines | Personal Automobile [Member] |  |
Segment Reporting Information [Line Items] |  |
Net premiums earned | 44,914 | 39,716
Standard Personal Lines | Homeowners [Member] |  |
Segment Reporting Information [Line Items] |  |
Net premiums earned | 35,013 | 31,187
Standard Personal Lines | Other Personal [Member] |  |
Segment Reporting Information [Line Items] |  |
Net premiums earned | 1,943 | 1,739
Standard Personal Lines | Miscellaneous income |  |
Segment Reporting Information [Line Items] |  |
Other income | 453 | 428
E&S Lines |  |
Segment Reporting Information [Line Items] |  |
Total revenues | 88,851 | 78,172
E&S Lines | Casualty Insurance Product Line [Member] |  |
Segment Reporting Information [Line Items] |  |
Net premiums earned | 60,817 | 54,624
E&S Lines | Property Insurance [Member] |  |
Segment Reporting Information [Line Items] |  |
Net premiums earned | $ 28,034 | $ 23,548

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