Reconciliation of Statutory Filings to Amounts Reported in the Consolidated Financial Statements - Reconciliations of Statutory Net (loss) Income and Capital and Surplus (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure Text Block [Abstract]
Statutory net income (loss) of insurance subsidiaries									$ 44,680,696	$ (33,246,417)	$ 1,677,549
Increases (decreases):
Deferred policy acquisition costs									(1,330,268)	325,267	3,980,664
Deferred federal income taxes									639,284	4,179,807	1,334,410
Salvage and subrogation recoverable									207,000	2,061,600	1,199,200
Consolidating eliminations and adjustments									(11,048,314)	(16,013,971)	(13,534,428)
Parent-only net income									14,003,346	9,933,374	12,458,705
Net income (loss)	$ 14,153,747	$ 5,186,379	$ 4,788,454	$ 23,023,164	$ (14,998,763)	$ 1,206,356	$ (789,855)	$ (18,178,078)	47,151,744	(32,760,340)	7,116,100
Statutory Capital And Surplus Of Insurance Subsidiaries [Abstract]
Statutory capital and surplus of insurance subsidiaries	418,449,596				364,518,536				418,449,596	364,518,536	407,125,532
Deferred policy acquisition costs	59,284,859				60,615,127				59,284,859	60,615,127	60,289,860	$ 56,309,196
Deferred federal income taxes	(15,477,843)				(20,094,374)				(15,477,843)	(20,094,374)	(14,422,511)
Salvage and subrogation recoverable	20,245,200				20,038,200				20,245,200	20,038,200	17,976,600
Non-admitted assets and other adjustments, net	1,727,754				1,904,083				1,727,754	1,904,083	1,960,089
Fixed maturities	(326,795)				(16,528,367)				(326,795)	(16,528,367)	(8,748,140)
Parent-only equity and other adjustments	(32,887,252)				(11,583,304)				(32,887,252)	(11,583,304)	(15,485,326)
Total stockholders' equity	$ 451,015,519				$ 398,869,901				$ 451,015,519	$ 398,869,901	$ 448,696,104	$ 438,615,320