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Significant Accounting Policies - Revenues From Contracts with Customers (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Revenue earned	$ 37,471,647	$ 36,771,629	$ 111,181,363	$ 107,353,244
Investment advisory
Disaggregation of Revenue [Line Items]
Revenue earned	34,928,205	33,782,603	103,085,767	98,105,905
Mutual fund administration, net
Disaggregation of Revenue [Line Items]
Revenue earned	2,543,442	2,989,026	8,095,596	9,247,339
Proprietary funds
Disaggregation of Revenue [Line Items]
Revenue earned	29,408,277	29,560,917	88,560,537	86,223,079
Proprietary funds | Investment advisory
Disaggregation of Revenue [Line Items]
Revenue earned	26,864,835	26,571,891	80,464,941	76,975,740
Proprietary funds | Mutual fund administration, net
Disaggregation of Revenue [Line Items]
Revenue earned	2,543,442	2,989,026	8,095,596	9,247,339
Sub-advised funds and institutional accounts
Disaggregation of Revenue [Line Items]
Revenue earned	8,063,370	7,210,712	22,620,826	21,130,165
Sub-advised funds and institutional accounts | Investment advisory
Disaggregation of Revenue [Line Items]
Revenue earned	8,063,370	7,210,712	22,620,826	21,130,165
Sub-advised funds and institutional accounts | Mutual fund administration, net
Disaggregation of Revenue [Line Items]
Revenue earned	$ 0	$ 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 32
-Paragraph 2A
-URI http://asc.fasb.org/extlink&oid=82859839&loc=SL82860478-203043

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130543-203045

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130539-203045

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130545-203045

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