Investments (Trading Securities FV) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Investment balances
Cost	$ 50,065	$ 65,875
Gross Unrealized Gains	259	232
Gross Unrealized Losses	0	(326)
Investments in trading securities	50,324	65,781
Trading Securities, Unrealized Holding Gain	259	232
Trading Securities, Unrealized Holding Loss	0	326
Trading Securities, Cost	50,065	65,875
Investment Owned, at Cost	53,735
Investments in trading securities	50,324	65,781
Unrealized Gain on Securities	827
Investment Owned, at Fair Value	54,562
Unrealized Gain (Loss) on Investments	3,296
U.S. Government and Government agency obligations
Investment balances
Cost	39,074	48,177
Gross Unrealized Gains	174	232
Gross Unrealized Losses	0	0
Investments in trading securities	39,248	48,409
Trading Securities, Unrealized Holding Gain	174	232
Trading Securities, Unrealized Holding Loss	0	0
Trading Securities, Cost	39,074	48,177
Investments in trading securities	39,248	48,409
Money market funds
Investment balances
Cost	4,592	10,354
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investments in trading securities	4,592	10,354
Trading Securities, Unrealized Holding Gain	0	0
Trading Securities, Unrealized Holding Loss	0	0
Trading Securities, Cost	4,592	10,354
Investments in trading securities	4,592	10,354
Equity funds
Investment balances
Cost	6,399	7,344
Gross Unrealized Gains	85	0
Gross Unrealized Losses		(326)
Investments in trading securities	6,484	7,018
Trading Securities, Unrealized Holding Gain	85	0
Trading Securities, Unrealized Holding Loss		326
Trading Securities, Cost	6,399	7,344
Investments in trading securities	6,484	$ 7,018
Private investment fund
Investment balances
Investment Owned, at Cost	250
Unrealized Gain on Securities	13
Investment Owned, at Fair Value	263
Private equity
Investment balances
Investment Owned, at Cost	3,420
Unrealized Gain on Securities	555
Investment Owned, at Fair Value	$ 3,975

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Value of the investment at close of period. For schedules of investments that are categorized, the value would be aggregated by category. For investment in and advances to affiliates, if operations of any controlled companies are different in character from those of the company, group such affiliates within divisions and by type of activities.

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