Segment Information - Summary of Financial Data by Segment (Detail) - USD ($) |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2018 |
Sep. 30, 2017 |
Sep. 30, 2018 |
Sep. 30, 2017 |
|
| Premiums earned: | ||||
| Premiums earned | $ 187,661,705 | $ 177,283,816 | $ 555,140,395 | $ 521,454,835 |
| Net investment income | 6,620,491 | 5,979,834 | 19,341,012 | 17,385,103 |
| Realized investment gains | 3,463,504 | 561,429 | 4,062,475 | 4,207,710 |
| Equity in earnings of DFSC | 732,768 | 403,647 | 2,152,738 | 1,023,212 |
| Other | 1,426,000 | 1,487,000 | 4,326,000 | 4,197,000 |
| Total revenues | 199,904,180 | 185,716,027 | 585,022,486 | 548,267,706 |
| Underwriting (loss) income: | ||||
| SAP underwriting (loss) income | (10,085,000) | 79,000 | (60,293,000) | (19,146,000) |
| GAAP adjustments | 332,000 | 644,000 | 5,106,000 | 6,423,000 |
| GAAP underwriting (loss) income | (9,753,000) | 723,000 | (55,187,000) | (12,723,000) |
| Net investment income | 6,620,491 | 5,979,834 | 19,341,012 | 17,385,103 |
| Realized investment gains | 3,463,504 | 561,429 | 4,062,475 | 4,207,710 |
| Equity in earnings of DFSC | 732,768 | 403,647 | 2,152,738 | 1,023,212 |
| Other | 213,000 | 844,000 | 1,040,000 | 1,947,000 |
| (Loss) income before income tax (benefit) expense | 1,276,986 | 8,512,050 | (28,591,231) | 11,840,410 |
| Commercial Lines [Member] | ||||
| Premiums earned: | ||||
| Premiums earned | 84,251,000 | 80,724,000 | 251,029,000 | 236,437,000 |
| Underwriting (loss) income: | ||||
| SAP underwriting (loss) income | 2,125,000 | 8,998,000 | (17,935,000) | 12,670,000 |
| Personal Lines [Member] | ||||
| Premiums earned: | ||||
| Premiums earned | 103,410,000 | 96,560,000 | 304,111,000 | 285,018,000 |
| Underwriting (loss) income: | ||||
| SAP underwriting (loss) income | $ (12,210,000) | $ (8,919,000) | $ (42,358,000) | $ (31,816,000) |