Investments - Summary of Gross Investment Gains and Losses before Applicable Income Taxes (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Gain (Loss) on Securities [Line Items]
Gross investment gains	$ 23,604,415	$ 2,022,422	$ 6,366,108
Gross investment losses	1,619,798	6,823,931	660,853
Net investment gains (losses)	21,984,617	(4,801,509)	5,705,255
Change in difference between fair value and cost of investments	47,981,583	(24,143,286)	3,905,577
Fixed Maturities [Member]
Gain (Loss) on Securities [Line Items]
Gross investment gains	470,983	131,660	168,855
Gross investment losses	323,746	630,904	98,723
Change in difference between fair value and cost of investments	38,647,456	(20,641,433)	2,335,578
Investments In Affiliates [Member]
Gain (Loss) on Securities [Line Items]
Gross investment gains	12,662,147
Equity Securities [Member]
Gain (Loss) on Securities [Line Items]
Gross investment gains	10,471,285	1,890,762	6,197,253
Gross investment losses	1,296,052	6,193,027	562,130
Change in difference between fair value and cost of investments	$ 9,334,127	$ (3,501,853)	$ 1,569,999