Note 2 - INVESTMENT SECURITIES (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) state issuer security	Mar. 31, 2023 USD ($)	Sep. 30, 2024 USD ($) state item issuer security	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) state issuer
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Number of securities | security	662		662
Aggregate losses of securities (as a percent)	7.20%		7.20%
Available-for-sale, unrealized loss positions, qualitative disclosure, number of positions | security	498		498
Available-for-sale, unrealized loss positions, qualitative disclosure, number of positions, greater than or equal to one year | security	459		459
Securities trading, at fair value	$ 58,685		$ 58,685		$ 22,369
Recognized trading gain (loss)	$ (200)		$ 53
Number of charters owning municipal securities | item			4
General Obligation Bonds
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Number of issuers | issuer	79		79		82
Other investments	$ 106,800		$ 106,800		$ 99,400
Number of states holding investments | state	17		17		18
General Obligation Bonds | Aggregate Fair Value Exceeding 5 Million
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Number of states holding investments | state	9		9		8
General Obligation Bonds | Aggregate Fair Value Exceeding 5 Million | Minimum
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Other investments	$ 5,000		$ 5,000		$ 5,000
Revenue Bonds
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Number of issuers | issuer	162		162		169
Other investments	$ 855,000		$ 855,000		$ 750,800
Number of states holding investments | state	31		31		31
Revenue Bonds | Aggregate Fair Value Exceeding 5 Million
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Number of states holding investments | state	13		13		15
Revenue Bonds | Aggregate Fair Value Exceeding 5 Million | Minimum
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Other investments	$ 5,000		$ 5,000		$ 5,000
Revenue Bonds | Aggregate Book Or Market Value Exceeded 5% of The Company Equity
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Number of issuers | issuer	2		2		2
Percentage threshold	5.00%		5.00%
Other securities
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Provision for credit loss expense				$ 989
Corporate securities
Debt Securities, Available-for-Sale, Unrealized Loss Position [Line Items]
Provision for credit loss expense		$ 989	$ (445)