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Investments - Summary of Gross Investment Gains and Losses before Applicable Income Taxes (Detail) - USD ($) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020
Gain (Loss) on Securities [Line Items] |  |  |  |
Gross investment gains | $ 4,241,000 | $ 6,703,000 | $ 7,252,000 | $ 4,007,000
Gross investment losses | 0 | 217,000 | 542,000 | 8,216,000
Net investment gains (losses) | 4,241,031 | 6,485,896 | 6,710,085 | (4,208,947)
Fixed Maturities [Member] |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Gross investment gains | 479,000 | 229,000 | 524,000 | 652,000
Gross investment losses | 0 | 217,000 | 74,000 | 218,000
Equity Securities [Member] |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |
Gross investment gains | 3,762,000 | 6,474,000 | 6,728,000 | 3,355,000
Gross investment losses | $ 0 | $ 0 | $ 468,000 | $ 7,998,000

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- Definition Amount of realized gain (loss) on investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.3(a)) -URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 + Details
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