Reinsurance - Ceded Reinsurance Transactions with Unaffiliated Reinsurers (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Ceded Credit Risk [Line Items]
Premiums written	$ 326,545,370	$ 320,956,412	$ 293,379,217
Premiums earned	326,198,234	310,179,267	282,646,219
Prepaid reinsurance premiums	135,379,777	135,032,641
Unaffiliated Entity [Member]
Ceded Credit Risk [Line Items]
Premiums written	50,160,604	51,241,267	45,354,233
Premiums earned	51,266,000	49,633,348	44,318,542
Losses and loss expenses	50,652,202	44,575,268	18,588,114
Prepaid reinsurance premiums	10,108,269	11,213,665	9,605,746
Liability for losses and loss expenses	$ 137,904,346	$ 116,689,871	$ 103,694,418