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Significant Accounting Policies - Revenue From Contracts with Customers (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 126,387,718	$ 136,624,380	$ 145,627,748
Investment advisory
Disaggregation of Revenue [Line Items]
Revenue	119,125,230	128,009,409	135,317,805
Mutual fund administration revenue, net
Disaggregation of Revenue [Line Items]
Revenue	7,262,488	8,614,971	10,309,943
Proprietary funds
Disaggregation of Revenue [Line Items]
Revenue	95,365,987	105,942,281	115,538,920
Proprietary funds | Investment advisory
Disaggregation of Revenue [Line Items]
Revenue	88,103,499	97,327,310	105,228,977
Proprietary funds | Mutual fund administration revenue, net
Disaggregation of Revenue [Line Items]
Revenue	7,262,488	8,614,971	10,309,943
Sub-advised funds and separately managed accounts
Disaggregation of Revenue [Line Items]
Revenue	31,021,731	30,682,099	30,088,828
Sub-advised funds and separately managed accounts | Investment advisory
Disaggregation of Revenue [Line Items]
Revenue	31,021,731	30,682,099	30,088,828
Sub-advised funds and separately managed accounts | Mutual fund administration revenue, net
Disaggregation of Revenue [Line Items]
Revenue	$ 0	$ 0	$ 0

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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