Concentration of Operations - Net Premiums Earned for the Top Ten States (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule Of Premiums Earned Net By Segment [Line Items]
Net premiums earned	$ 271,698	$ 275,993	$ 304,427
Premium earned percentage	100.00%	100.00%	100.00%
Florida [Member]
Schedule Of Premiums Earned Net By Segment [Line Items]
Net premiums earned	$ 31,955	$ 31,514	$ 34,617
Premium earned percentage	11.80%	11.40%	11.40%
Georgia [Member]
Schedule Of Premiums Earned Net By Segment [Line Items]
Net premiums earned	$ 30,831	$ 34,772	$ 37,926
Premium earned percentage	11.30%	12.60%	12.50%
Pennsylvania [Member]
Schedule Of Premiums Earned Net By Segment [Line Items]
Net premiums earned	$ 21,017	$ 19,574	$ 24,340
Premium earned percentage	7.70%	7.10%	8.00%
Louisiana [Member]
Schedule Of Premiums Earned Net By Segment [Line Items]
Net premiums earned	$ 21,804	$ 20,476	$ 22,668
Premium earned percentage	8.00%	7.40%	7.40%
North Carolina [Member]
Schedule Of Premiums Earned Net By Segment [Line Items]
Net premiums earned	$ 17,883	$ 15,964	$ 17,338
Premium earned percentage	6.60%	5.80%	5.70%
Illinois [Member]
Schedule Of Premiums Earned Net By Segment [Line Items]
Net premiums earned	$ 12,209	$ 13,680	$ 14,802
Premium earned percentage	4.50%	5.00%	4.90%
Virginia [Member]
Schedule Of Premiums Earned Net By Segment [Line Items]
Net premiums earned	$ 11,537	$ 12,579	$ 14,041
Premium earned percentage	4.30%	4.60%	4.60%
Minnesota [Member]
Schedule Of Premiums Earned Net By Segment [Line Items]
Net premiums earned	$ 9,827	$ 10,612	$ 11,057
Premium earned percentage	3.60%	3.80%	3.60%
Wisconsin [Member]
Schedule Of Premiums Earned Net By Segment [Line Items]
Net premiums earned	$ 12,007	$ 13,108	$ 12,263
Premium earned percentage	4.40%	4.70%	4.00%
South Carolina [Member]
Schedule Of Premiums Earned Net By Segment [Line Items]
Net premiums earned	$ 9,808	$ 9,186	$ 11,270
Premium earned percentage	3.60%	3.30%	3.70%
All Others [Member]
Schedule Of Premiums Earned Net By Segment [Line Items]
Net premiums earned	$ 92,820	$ 94,528	$ 104,105
Premium earned percentage	34.20%	34.30%	34.20%