Note 9 - Derivative Financial Instruments - Statement of Operations Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Derivative financial instruments	$ 25,358	$ 2,960	$ 25,749	$ 5,598
TBA and Other Forward MBS [Member] | Revenue Net Trading [Member]
Derivative financial instruments	1,531	2,960	1,922	5,598
Equity Derivatives [Member] | Principal Transactions and Other Income (Loss) [Member]
Derivative financial instruments	788	0	788	0
Share Forward Liabilities [Member] | Revenue Net Trading [Member]
Derivative financial instruments	$ 23,039	$ 0	$ 23,039	$ 0