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v3.22.0.1

Segment Information (Revenue From Continuing Operations by Segment) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | $ 3,017,253 | $ 2,681,814 | $ 2,597,171
Other income | 17,723 | 17,570 | 12,355
Net investment income | 326,589 | 227,107 | 222,543
Net realized and unrealized investment gains (losses) | 17,599 | (4,217) | 14,422
Total investment revenues | 344,188 | 222,890 | 236,965
Total revenues | 3,379,164 | 2,922,274 | 2,846,491
Standard Commercial Lines [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Other income | 16,056 | 15,512 | 10,889
Total revenues | 2,459,941 | 2,158,696 | 2,060,503
Standard Personal Lines |  |  |
Revenue from External Customer [Line Items] |  |  |
Other income | 1,667 | 2,058 | 1,466
Total revenues | 295,226 | 301,198 | 309,205
E&S Lines [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Total revenues | 279,809 | 239,490 | 239,818
Commercial Automobile [Member] | Standard Commercial Lines [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | 436,412 | 388,120 | 353,834
Workers Compensation [Member] | Standard Commercial Lines [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | 306,428 | 278,062 | 311,370
General Liability [Member] | Standard Commercial Lines [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | 807,158 | 694,019 | 669,895
Commercial Property [Member] | Standard Commercial Lines [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | 724,398 | 615,181 | 554,256
Business Owners' Policies [Member] | Standard Commercial Lines [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | 110,622 | 110,210 | 105,252
Bonds Segment [Member] | Standard Commercial Lines [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | 35,762 | 36,742 | 35,726
Other Commercial [Member] | Standard Commercial Lines [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | 23,105 | 20,850 | 19,281
Personal Automobile [Member] | Standard Personal Lines |  |  |
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | 163,007 | 165,020 | 172,606
Homeowners [Member] | Standard Personal Lines |  |  |
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | 122,526 | 125,405 | 127,543
Other Personal [Member] | Standard Personal Lines |  |  |
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | 8,026 | 8,715 | 7,590
Casualty Insurance Product Line [Member] | E&S Lines [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | 197,779 | 174,408 | 182,864
Property Insurance [Member] | E&S Lines [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Net premiums earned | $ 82,030 | $ 65,082 | $ 56,954

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