Note 23 - Related Party Transactions - Routine Transactions Recognized in the Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Investment banking and new issue	$ 17	$ 0	$ 1,792	$ 0
Asset management	242	395	541	791
Principal transactions and other income	201	(44)	230	89
Income (loss) from equity method affiliates	(3,038)	(1,437)	(3,565)	981	$ (16,763)
Operating expense (income)	(26)	(10)	(52)	16
Interest expense (income)	76	288	197	574
BTC Development Corp SPAC IPO [Member]
Investment banking and new issue	6	0	269	0
Columbus Circle II SPAC [Member]
Investment banking and new issue	0	0	991	0
Principal transactions and other income	30	0	45	0
Income (loss) from equity method affiliates	(2,968)	0	(3,666)	0
Crane Harbor Acquisition I [Member]
Investment banking and new issue	0	0	156	0
Crane Harbor Acquisition II [Member]
Investment banking and new issue	11	0	376	0
CREO JV [Member]
Asset management	66	131	154	282
Principal transactions and other income	(94)	(105)	(142)	(33)
U.S. Insurance JV [Member]
Asset management	176	264	387	509
Principal transactions and other income	31	46	80	107
Columbus Circle SPAC [Member]
Principal transactions and other income	0	15	0	15
Income (loss) from equity method affiliates	0	(1,307)	0	(1,307)
CK Capital Value Fund [Member]
Principal transactions and other income	234	0	247	0
Dutch Real Estate Entities [Member]
Income (loss) from equity method affiliates	(70)	533	(353)	849
Other SPAC Sponsor Entities [Member]
Income (loss) from equity method affiliates	0	(663)	454	1,439
Equity Method Affiliates [Member]
Income (loss) from equity method affiliates	(3,038)	(1,437)	(3,565)	981
Cohen Circle LLC [Member]
Operating expense (income)	(26)	(10)	(52)	16
JKD Investor [Member]
Interest expense (income)	$ 76	$ 288	$ 197	$ 574