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v3.20.4

Segment Information (Revenue From Continuing Operations by Segment) (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2020 | Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Dec. 31, 2019 | Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned | $ 704,899 | $ 694,541 | $ 630,671 | $ 651,703 | $ 668,359 | $ 653,620 | $ 642,619 | $ 632,573 | $ 2,681,814 | $ 2,597,171 | $ 2,436,229
Other income | 4,943 | 6,119 | 4,683 | 1,825 | 3,820 | 3,162 | 3,053 | 2,320 | 17,570 | 12,355 | 9,438
Net investment income | 68,511 | 68,185 | 34,444 | 55,967 | 57,594 | 55,826 | 58,505 | 50,618 | 227,107 | 222,543 | 195,336
Net realized and unrealized investment (losses) gain | 20,079 | 7,721 | 12,649 | (44,666) | (873) | (2,183) | 4,027 | 13,451 | (4,217) | 14,422 | (54,923)
Total investment revenues |  |  |  |  |  |  |  |  | 222,890 | 236,965 | 140,413
Total revenues | $ 798,432 | $ 776,566 | $ 682,447 | $ 664,829 | $ 728,900 | $ 710,425 | $ 708,204 | $ 698,962 | 2,922,274 | 2,846,491 | 2,586,080
Standard Commercial Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Other income |  |  |  |  |  |  |  |  | 15,512 | 10,889 | 8,180
Total revenues |  |  |  |  |  |  |  |  | 2,158,696 | 2,060,503 | 1,920,402
Standard Personal Lines |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Other income |  |  |  |  |  |  |  |  | 2,058 | 1,466 | 1,257
Total revenues |  |  |  |  |  |  |  |  | 301,198 | 309,205 | 305,698
E&S Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Other income |  |  |  |  |  |  |  |  | 0 | 0 | 1
Total revenues |  |  |  |  |  |  |  |  | 239,490 | 239,818 | 219,567
Commercial Automobile [Member] | Standard Commercial Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 615,181 | 554,256 | 493,093
Workers Compensation [Member] | Standard Commercial Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 278,062 | 311,370 | 317,616
General Liability [Member] | Standard Commercial Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 694,019 | 669,895 | 616,187
Commercial Property [Member] | Standard Commercial Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 388,120 | 353,834 | 329,660
Business Owners' Policies [Member] | Standard Commercial Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 110,210 | 105,252 | 103,412
Bonds Segment [Member] | Standard Commercial Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 36,742 | 35,726 | 33,991
Other Commercial [Member] | Standard Commercial Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 20,850 | 19,281 | 18,263
Personal Automobile [Member] | Standard Personal Lines |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 165,020 | 172,606 | 168,250
Homeowners [Member] | Standard Personal Lines |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 125,405 | 127,543 | 128,961
Other Personal [Member] | Standard Personal Lines |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 8,715 | 7,590 | 7,230
Casualty Insurance Product Line [Member] | E&S Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 174,408 | 182,864 | 164,313
Property Insurance [Member] | E&S Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | $ 65,082 | $ 56,954 | $ 55,253

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