Note 10 - Collateralized Securities Transactions (Details Textual) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2022 USD ($)
Securities Purchased under Agreements to Resell, Total	$ 543,783		$ 543,783		$ 408,408
Fair Value of Securities Received as Collateral that Can be Resold or Repledged	550,846		550,846		415,057
Securities Sold under Agreements to Repurchase	545,993		545,993		408,203
Fair Value of Securities Received as Collateral that Have Been Resold or Repledged	550,846		550,846		$ 415,057
Revenues	$ 31,695	$ 17,121	$ 61,057	$ 48,517
Securities Sold under Agreements to Repurchase, Average Rate Paid			5.85%		6.10%
Securities Purchased under Agreements to Resell, Average Rate			6.45%		6.87%
Gestational Repo Business [Member]
Number of Counterparties Related to Reverse Repurchase Agreements	7		7		7
Revenues	$ 3,843	$ 4,060	$ 10,992	12,456
First Guaranty Mortgage Corporation [Member]
Securities Purchased under Agreements to Resell, Total						$ 269,228
Gain (Loss) on Sale of Collateral			4	$ (1,787)
First Guaranty Mortgage Corporation [Member] | Residential Mortgage [Member]
Securities Purchased under Agreements to Resell, Total	$ 0		$ 0		$ 3,113