Note 4 - SECURITIZATIONS AND VARIABLE INTEREST ENTITIES - VIE (Details) $ in Thousands		3 Months Ended	9 Months Ended	12 Months Ended
	Aug. 15, 2024 USD ($) item	Sep. 30, 2024 USD ($)	Sep. 30, 2024 USD ($)	Dec. 31, 2023 USD ($) item	Sep. 30, 2023 USD ($)
Securitizations and Variable Interest Entities
Number of sponsored securitizations completed | item				2
Trading securities		$ 58,685	$ 58,685	$ 22,369
Recognized net loss on sale		(200)	53
Total assets		9,088,565	9,088,565	8,538,894	$ 8,540,057
Liabilities		8,111,945	8,111,945	7,652,298
Tax exempt LIHTC loans
Securitizations and Variable Interest Entities
Trading securities	$ 36,700
Recognized net loss on sale	473
M-series Tax exempt LIHTC loans
Securitizations and Variable Interest Entities
Securities pledged	$ 230,700
Number of securities issued | item	2
Class B Certificates
Securitizations and Variable Interest Entities
Percentage of first loss support	15.00%
Class B Certificates | Assets pledged as collateral
Securitizations and Variable Interest Entities
Amount of first loss support	$ 34,900
Class A certificates | Assets pledged as collateral
Securitizations and Variable Interest Entities
Securities pledged	$ 10,100
VIE
Securitizations and Variable Interest Entities
Total assets		58,700	58,700	22,400
Liabilities		0	0	$ 0
Maximum exposure to loss		$ 66,600	$ 66,600