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Significant Accounting Policies - Mutual Fund Administration Gross and Net Revenue (Detail) - USD ($) | 3 Months Ended
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Mar. 31, 2023 | Mar. 31, 2022
Revenue from External Customer [Line Items] |  |
Revenue | $ 33,990,503 | $ 42,256,386
Administration revenue, gross |  |
Revenue from External Customer [Line Items] |  |
Revenue | 5,416,875 | 6,940,172
Fund related expense |  |
Revenue from External Customer [Line Items] |  |
Expenses | 3,468,831 | 3,962,672
Mutual fund administration revenue, net |  |
Revenue from External Customer [Line Items] |  |
Revenue | $ 1,948,044 | $ 2,977,500

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