Segment Information, Financial Data by Segment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Premiums earned [Abstract]
Premiums earned	$ 776,015,201	$ 742,040,339	$ 756,078,400
Net investment income	31,125,631	29,504,466	29,514,955
Investment gains	6,477,286	2,777,919	21,984,617
Equity in earnings of DFSC	0	0	295,000
Total revenues	816,465,791	777,819,910	812,451,471
Underwriting (loss) income [Abstract]
Net investment income	31,125,631	29,504,466	29,514,955
Investment gains	6,477,286	2,777,919	21,984,617
Equity in earnings of DFSC	0	0	295,000
Income before income tax expense	30,338,508	63,272,503	57,081,030
Operating Segments [Member]
Premiums earned [Abstract]
Premiums earned	776,015,000	742,040,000	756,078,000
Net investment income	31,126,000	29,504,000	29,515,000
Investment gains	6,477,000	2,778,000	21,985,000
Equity in earnings of DFSC	0	0	295,000
Other	2,848,000	3,497,000	4,578,000
Total revenues	816,466,000	777,819,000	812,451,000
Underwriting (loss) income [Abstract]
SAP underwriting (loss) income	(17,939,000)	30,906,000	6,787,000
GAAP adjustments	9,945,000	(959,000)	(3,079,000)
GAAP underwriting (loss) income	(7,994,000)	29,947,000	3,708,000
Net investment income	31,126,000	29,504,000	29,515,000
Investment gains	6,477,000	2,778,000	21,985,000
Equity in earnings of DFSC	0	0	295,000
Other	730,000	1,043,000	1,578,000
Income before income tax expense	30,339,000	63,272,000	57,081,000
Commercial Lines [Member] | Operating Segments [Member]
Premiums earned [Abstract]
Premiums earned	468,433,000	412,877,000	385,465,000
Underwriting (loss) income [Abstract]
SAP underwriting (loss) income	(35,174,000)	(858,000)	8,404,000
Personal Lines [Member] | Operating Segments [Member]
Premiums earned [Abstract]
Premiums earned	307,582,000	329,163,000	370,613,000
Underwriting (loss) income [Abstract]
SAP underwriting (loss) income	$ 17,235,000	$ 31,764,000	$ (1,617,000)