Segment Information - Summary of Financial Data by Segment (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenues:
Net premiums earned	$ 126,963,328	$ 117,569,122	$ 251,665,369	$ 232,260,913
GAAP adjustments		(3,000)		(6,000)
GAAP premiums earned	126,963,000	117,569,000	251,665,000	232,261,000
Net investment income	4,670,558	4,919,288	9,486,001	10,009,010
Realized investment gains	1,253,982	1,528,333	2,594,546	3,838,313
Equity in earnings of DFSC	675,568	1,110,256	1,764,474	2,284,775
Other	1,944,000	2,173,000	3,870,000	4,254,000
Total revenues	135,507,635	127,299,190	269,380,227	252,647,352
Underwriting income (loss):
SAP underwriting loss	(6,527,000)	(9,972,000)	(7,894,000)	(10,254,000)
GAAP adjustments	2,591,000	3,572,000	4,340,000	4,519,000
GAAP underwriting income (loss)	(3,936,000)	(6,400,000)	(3,554,000)	(5,735,000)
Net investment income	4,671,000	4,919,000	9,486,000	10,009,000
Realized investment gains	1,253,982	1,528,333	2,594,546	3,838,313
Equity in earnings of DFSC	675,568	1,110,256	1,764,474	2,284,775
Other	197,000	958,000	654,000	1,566,000
Income before income tax expense	2,862,158	2,115,082	10,945,447	11,962,816
Operating Segments [Member] | Commercial Lines [Member]
Revenues:
Net premiums earned	49,612,000	42,946,000	97,243,000	83,783,000
Underwriting income (loss):
GAAP underwriting income (loss)	(3,079,000)	(157,000)	(4,670,000)	2,320,000
Operating Segments [Member] | Personal Lines [Member]
Revenues:
Net premiums earned	77,351,000	74,626,000	154,422,000	148,484,000
Underwriting income (loss):
GAAP underwriting income (loss)	$ (3,448,000)	$ (9,815,000)	$ (3,224,000)	$ (12,574,000)