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v3.3.1.900

Segment Information (Revenue From Continuing Operations by Segment) (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2015 | Sep. 30, 2015 | Jun. 30, 2015 | Mar. 31, 2015 | Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned | $ 516,087 | $ 507,390 | $ 490,309 | $ 476,123 | $ 469,850 | $ 462,639 | $ 463,625 | $ 456,495 | $ 1,989,909 | $ 1,852,609 | $ 1,736,072
Other income |  |  |  |  |  |  |  |  | 7,456 | 16,945 | 12,294
Net investment income | $ 30,108 | $ 32,061 | $ 32,230 | $ 26,917 | $ 32,108 | $ 34,292 | $ 36,774 | $ 35,534 | 121,316 | 138,708 | 134,643
Net realized gains |  |  |  |  |  |  |  |  | 13,171 | 26,599 | 20,732
Total investment revenues |  |  |  |  |  |  |  |  | 134,487 | 165,307 | 155,375
Total all segments |  |  |  |  |  |  |  |  | 2,131,852 | 2,034,514 | 1,903,648
Total revenues |  |  |  |  |  |  |  |  | 2,131,852 | 2,034,861 | 1,903,741
Miscellaneous Income [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Other income |  |  |  |  |  |  |  |  | 7,456 | 16,598 | 12,201
Other Income [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Other income |  |  |  |  |  |  |  |  | 0 | 347 | 93
Standard Commercial Lines [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 358,909 | 333,310 | 310,994
Standard Commercial Lines [Member] | Workers' Compensation [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 290,075 | 274,585 | 267,612
Standard Commercial Lines [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 483,291 | 444,938 | 405,322
Standard Commercial Lines [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 269,022 | 244,792 | 224,412
Standard Commercial Lines [Member] | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 93,428 | 85,788 | 77,097
Standard Commercial Lines [Member] | Bonds Segment [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 20,350 | 19,288 | 19,000
Standard Commercial Lines [Member] | Other Commercial [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 14,367 | 13,011 | 12,182
Standard Commercial Lines [Member] | Miscellaneous Income [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 6,343 | 14,747 | 10,253
Standard Commercial Lines [Member] | Total standard Commercial Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 1,535,785 | 1,430,459 | 1,326,872
Property and Casualty, Personal Insurance Product Line [Member] | Miscellaneous Income [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 1,113 | 1,834 | 1,948
Property and Casualty, Personal Insurance Product Line [Member] | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 146,784 | 151,317 | 152,005
Property and Casualty, Personal Insurance Product Line [Member] | Homeowners [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 134,382 | 134,273 | 127,991
Property and Casualty, Personal Insurance Product Line [Member] | Other Personal [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 6,968 | 11,157 | 14,336
Property and Casualty, Personal Insurance Product Line [Member] | Property and Casualty, Personal Insurance Product Line [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 289,247 | 298,581 | 296,280
E&S Lines [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 7,795 | 5,436 | 4,306
E&S Lines [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 121,802 | 96,142 | 88,761
E&S Lines [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | 42,736 | 38,572 | 32,054
E&S Lines [Member] | Miscellaneous Income [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Other income |  |  |  |  |  |  |  |  | 0 | 17 | 0
E&S Lines [Member] | Total standard Commercial Lines [Member] |  |  |  |  |  |  |  |  |  |  |
Revenue from External Customer [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net premiums earned |  |  |  |  |  |  |  |  | $ 172,333 | $ 140,167 | $ 125,121

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