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Investments - Summary of Gross Investment Gains and Losses before Applicable Income Taxes (Detail) - USD ($) | 12 Months Ended
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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

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