Investments - Investments, Fair Value (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity Investments, at Fair Value, Cost	$ 44,251	$ 23,814
Equity Investments, at Fair Value, Unrealized Gain/(Loss)	4,789	2,239
Equity Investments, at Fair Value	49,040	26,053
Securities Short Sold Proceeds	833	620
Securities Short Sold Unrealized (Gain)/Loss	37	94
Securities Short Sold,Fair Value	870	714
Equity Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity Investments, at Fair Value, Cost	36,938	16,521
Equity Investments, at Fair Value, Unrealized Gain/(Loss)	4,776	2,218
Equity Investments, at Fair Value	41,714	18,739
Securities Short Sold Proceeds	833	620
Securities Short Sold Unrealized (Gain)/Loss	37	94
Securities Short Sold,Fair Value	870	714
Mutual Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity Investments, at Fair Value, Cost	7,313	7,293
Equity Investments, at Fair Value, Unrealized Gain/(Loss)	13	21
Equity Investments, at Fair Value	$ 7,326	$ 7,314