Transactions with Affiliates - Schedule of Affiliated Reinsurance Transactions on Net Premiums Our Insurance Subsidiaries Earned (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Ceded Credit Risk [Line Items]
Assumed	$ 473,512,866	$ 451,515,575	$ 423,129,271
Ceded	(326,198,234)	(310,179,267)	(282,646,219)
Net	198,580,547	190,924,704	184,656,732
Insurance Subsidiaries [Member]
Ceded Credit Risk [Line Items]
Assumed	473,512,781	451,470,623	422,984,409
Ceded	(274,932,234)	(260,545,919)	(238,327,677)
Net	$ 198,580,547	$ 190,924,704	$ 184,656,732