Investments - Marketable Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Investment Securities - fair value
Cost	$ 91,287	$ 80,912
Fair Value	89,311	76,999
Sponsored funds
Investment Securities - fair value
Cost	77,563	67,472
Fair Value	73,381	62,744
Equity securities
Investment Securities - fair value
Cost	13,724	13,440
Fair Value	$ 15,930	$ 14,255

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483467/210-10-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482736/825-10-45-1A

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant