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Concentration of Operations - Net Premiums Earned for the Top Ten States (Detail) - 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
Schedule Of Premiums Earned Net By Segment [Line Items] |  |  |  |  |  |  |  |  |  |  |
Premiums earned | $ 95,034 | $ 90,504 | $ 95,569 | $ 94,787 | $ 97,070 | $ 95,928 | $ 93,516 | $ 89,233 | $ 375,894 | $ 375,747 | $ 329,983
Premium earned percentage |  |  |  |  |  |  |  |  | 100.00% | 100.00% | 100.00%
Georgia [Member] |  |  |  |  |  |  |  |  |  |  |
Schedule Of Premiums Earned Net By Segment [Line Items] |  |  |  |  |  |  |  |  |  |  |
Premiums earned |  |  |  |  |  |  |  |  | $ 40,497 | $ 36,761 | $ 30,096
Premium earned percentage |  |  |  |  |  |  |  |  | 10.80% | 9.80% | 9.10%
Louisiana [Member] |  |  |  |  |  |  |  |  |  |  |
Schedule Of Premiums Earned Net By Segment [Line Items] |  |  |  |  |  |  |  |  |  |  |
Premiums earned |  |  |  |  |  |  |  |  | $ 38,874 | $ 47,643 | $ 42,110
Premium earned percentage |  |  |  |  |  |  |  |  | 10.30% | 12.70% | 12.80%
Pennsylvania [Member] |  |  |  |  |  |  |  |  |  |  |
Schedule Of Premiums Earned Net By Segment [Line Items] |  |  |  |  |  |  |  |  |  |  |
Premiums earned |  |  |  |  |  |  |  |  | $ 36,294 | $ 35,488 | $ 28,880
Premium earned percentage |  |  |  |  |  |  |  |  | 9.70% | 9.40% | 8.80%
Florida [Member] |  |  |  |  |  |  |  |  |  |  |
Schedule Of Premiums Earned Net By Segment [Line Items] |  |  |  |  |  |  |  |  |  |  |
Premiums earned |  |  |  |  |  |  |  |  | $ 24,792 | $ 20,691 | $ 12,950
Premium earned percentage |  |  |  |  |  |  |  |  | 6.60% | 5.50% | 3.90%
Illinois [Member] |  |  |  |  |  |  |  |  |  |  |
Schedule Of Premiums Earned Net By Segment [Line Items] |  |  |  |  |  |  |  |  |  |  |
Premiums earned |  |  |  |  |  |  |  |  | $ 23,285 | $ 20,606 | $ 18,445
Premium earned percentage |  |  |  |  |  |  |  |  | 6.20% | 5.50% | 5.60%
North Carolina [Member] |  |  |  |  |  |  |  |  |  |  |
Schedule Of Premiums Earned Net By Segment [Line Items] |  |  |  |  |  |  |  |  |  |  |
Premiums earned |  |  |  |  |  |  |  |  | $ 20,062 | $ 20,872 | $ 21,019
Premium earned percentage |  |  |  |  |  |  |  |  | 5.30% | 5.60% | 6.40%
Virginia [Member] |  |  |  |  |  |  |  |  |  |  |
Schedule Of Premiums Earned Net By Segment [Line Items] |  |  |  |  |  |  |  |  |  |  |
Premiums earned |  |  |  |  |  |  |  |  | $ 15,656 | $ 16,764 | $ 15,751
Premium earned percentage |  |  |  |  |  |  |  |  | 4.20% | 4.50% | 4.80%
Texas [Member] |  |  |  |  |  |  |  |  |  |  |
Schedule Of Premiums Earned Net By Segment [Line Items] |  |  |  |  |  |  |  |  |  |  |
Premiums earned |  |  |  |  |  |  |  |  | $ 15,226 | $ 14,846 | $ 14,949
Premium earned percentage |  |  |  |  |  |  |  |  | 4.00% | 4.00% | 4.50%
Minnesota [Member] |  |  |  |  |  |  |  |  |  |  |
Schedule Of Premiums Earned Net By Segment [Line Items] |  |  |  |  |  |  |  |  |  |  |
Premiums earned |  |  |  |  |  |  |  |  | $ 14,618 | $ 13,159 | $ 10,470
Premium earned percentage |  |  |  |  |  |  |  |  | 3.90% | 3.50% | 3.20%
Oklahoma [Member] |  |  |  |  |  |  |  |  |  |  |
Schedule Of Premiums Earned Net By Segment [Line Items] |  |  |  |  |  |  |  |  |  |  |
Premiums earned |  |  |  |  |  |  |  |  | $ 13,420 | $ 16,599 | $ 17,473
Premium earned percentage |  |  |  |  |  |  |  |  | 3.60% | 4.40% | 5.30%
All Others [Member] |  |  |  |  |  |  |  |  |  |  |
Schedule Of Premiums Earned Net By Segment [Line Items] |  |  |  |  |  |  |  |  |  |  |
Premiums earned |  |  |  |  |  |  |  |  | $ 133,170 | $ 132,318 | $ 117,840
Premium earned percentage |  |  |  |  |  |  |  |  | 35.40% | 35.10% | 35.60%

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