Investments (Trading Securities FV) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Investment balances
Cost	$ 25,232	$ 32,717
Gross Unrealized Gains	824	320
Gross Unrealized Losses	(308)	(363)
Investments in trading securities	25,748	32,674
Trading Securities, Unrealized Holding Gain	824	320
Trading Securities, Unrealized Holding Loss	308	363
Trading Securities, Cost	25,232	32,717
Investment Owned, at Cost	26,788	32,982
Investments in trading securities	25,748	32,674
Unrealized Gain on Securities	1,226	327
Unrealized Loss on Securities	(320)	(394)
Investment Owned, at Fair Value	27,694	32,915
Unrealized Gain (Loss) on Investments	0	6	$ (1,495)
U.S. Government securities
Investment balances
Cost	15,859	22,522
Gross Unrealized Gains	263	14
Gross Unrealized Losses	(66)	(75)
Investments in trading securities	16,056	22,461
Trading Securities, Unrealized Holding Gain	263	14
Trading Securities, Unrealized Holding Loss	66	75
Trading Securities, Cost	15,859	22,522
Investments in trading securities	16,056	22,461
Money market funds
Investment balances
Cost	7,629	5,367
Gross Unrealized Gains	174	111
Gross Unrealized Losses	0	0
Investments in trading securities	7,803	5,478
Trading Securities, Unrealized Holding Gain	174	111
Trading Securities, Unrealized Holding Loss	0	0
Trading Securities, Cost	7,629	5,367
Investments in trading securities	7,803	5,478
Equity funds
Investment balances
Cost	1,432	4,295
Gross Unrealized Gains	318	195
Gross Unrealized Losses	(132)	(260)
Investments in trading securities	1,618	4,230
Trading Securities, Unrealized Holding Gain	318	195
Trading Securities, Unrealized Holding Loss	132	260
Trading Securities, Cost	1,432	4,295
Investments in trading securities	1,618	4,230
Private investment fund
Investment balances
Investment Owned, at Cost	1,556	265
Unrealized Gain on Securities	402	7
Unrealized Loss on Securities	(12)	(31)
Investment Owned, at Fair Value	1,946	241
Equity Securities
Investment balances
Cost		381
Gross Unrealized Gains		0
Gross Unrealized Losses		(24)
Investments in trading securities		357
Trading Securities, Unrealized Holding Gain		0
Trading Securities, Unrealized Holding Loss		24
Trading Securities, Cost		381
Investments in trading securities		357
Debt Securities, Trading, Amortized Cost	183
Debt Securities, Trading, Unrealized Gain	69
Debt Securities, Trading, Unrealized Loss	(108)
Debt Securities, Trading	144
us-gaap_EquitySecuritiesMember
Investment balances
Debt Securities, Trading, Amortized Cost	129	152
Debt Securities, Trading, Unrealized Gain	0	0
Debt Securities, Trading, Unrealized Loss	(2)	(4)
Debt Securities, Trading	$ 127	$ 148