Investments - Schedule of Marketable Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Investment Securities - fair value
Cost	$ 21,017	$ 63,703
Fair Value	23,651	59,271
Sponsored funds
Investment Securities - fair value
Cost	10,991	43,507
Fair Value	12,366	40,191
Equity securities
Investment Securities - fair value
Cost	9,982	16,380
Fair Value	11,257	16,981
Debt securities
Investment Securities - fair value
Cost	44	3,816
Fair Value	$ 28	$ 2,099