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Significant Accounting Policies - Revenue From Contracts with Customers (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Revenue	$ 145,627,748	$ 145,201,729	$ 136,103,075
Investment advisory
Disaggregation of Revenue [Line Items]
Revenue	135,317,805	132,688,462	121,645,149
Mutual fund administration revenue, net
Disaggregation of Revenue [Line Items]
Revenue	10,309,943	12,513,267	14,457,926
Proprietary funds
Disaggregation of Revenue [Line Items]
Revenue	115,538,920	116,746,848	103,319,576
Proprietary funds | Investment advisory
Disaggregation of Revenue [Line Items]
Revenue	105,228,977	104,233,581	88,861,650
Proprietary funds | Mutual fund administration revenue, net
Disaggregation of Revenue [Line Items]
Revenue	10,309,943	12,513,267	14,457,926
Sub-advised funds and institutional accounts
Disaggregation of Revenue [Line Items]
Revenue	30,088,828	28,454,881	32,783,499
Sub-advised funds and institutional accounts | Investment advisory
Disaggregation of Revenue [Line Items]
Revenue	30,088,828	28,454,881	32,783,499
Sub-advised funds and institutional 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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

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