v3.19.3

Investments - Additional Information (Detail)		9 Months Ended		12 Months Ended
	Nov. 30, 2013 USD ($)	Sep. 30, 2019 USD ($) Securities	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Schedule of Investments [Line Items]
Net unrealized losses arising prior to reclassification date	$ 15,100,000
Amortization of unrealized losses recorded in accumulated other comprehensive income (loss)		$ 870,186	$ 912,229
Accumulated other comprehensive loss		418,394		$ (14,228,059)
Gain on equity securities		6,700,000	3,900,000
Loss on equity securities		1,200,000	$ 1,600,000
Obligations of States and Political Subdivisions [Member]
Schedule of Investments [Line Items]
Aggregate fair value of bond held		170,900,000		157,700,000
Amortized cost of bond held		160,400,000		152,200,000
Special Revenue Bonds [Member]
Schedule of Investments [Line Items]
Aggregate fair value of bond held		84,900,000		84,300,000
Amortized cost of bond held		$ 78,400,000		$ 80,900,000
Education Bonds [Member]
Schedule of Investments [Line Items]
Percentage of investments in special revenue bonds		45.00%		49.00%
Water and Sewer Utility Bonds [Member]
Schedule of Investments [Line Items]
Percentage of investments in special revenue bonds		34.00%		29.00%
Fixed Maturities [Member]
Schedule of Investments [Line Items]
Number of fixed maturity securities classified as available for sale | Securities		131
Accumulated Net Unrealized Investment Losses [Member]
Schedule of Investments [Line Items]
Accumulated other comprehensive loss		$ (7,800,000)		$ (8,600,000)
Minimum [Member]
Schedule of Investments [Line Items]
Percentage of which the company held security of any issuer		10.00%		10.00%

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