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Significant Accounting Policies - Mutual Fund Administration Gross and Net Revenue (Detail) - USD ($) | 3 Months Ended
--- | ---
Mar. 31, 2025 | Mar. 31, 2024
Revenue from External Customer [Line Items] |  |
Revenue | $ 37,116,210 | $ 36,294,930
Administration revenue, gross |  |
Revenue from External Customer [Line Items] |  |
Revenue | 6,642,148 | 5,718,610
Fund related expense |  |
Revenue from External Customer [Line Items] |  |
Expenses | 4,834,749 | 3,775,473
Fund administration revenue, net |  |
Revenue from External Customer [Line Items] |  |
Revenue | $ 1,807,399 | $ 1,943,137

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