Note 3 - Investment Securities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) item security	Dec. 31, 2020 USD ($)	Dec. 31, 2021 USD ($) item
Sale of securities portfolio | $	$ 111,400
Number of securities | security	695
Available-for-sale, unrealized loss positions, qualitative disclosure, number of positions | security	607
Aggregate losses of securities (as a percent)	11.81%
Available-for-sale, unrealized loss positions, qualitative disclosure, number of positions, greater than or equal to one year | security	39
Gain on sale | $		$ 2,553
Number Of Charters Owning Municipal Securities	4
Public deposits, FHLB advances, customer repurchase agreements, derivative liabilities
Investment securities pledged | $	$ 47,000		$ 246,500
Revenue Bonds
Number of issuers	2		2
Percentage threshold	5.00%		5.00%
Municipal securities | General Obligation Bonds
Number of issuers	118		113
Other investments | $	$ 110,600		$ 114,500
Number of states holding investments	22		20
Municipal securities | General Obligation Bonds | Minimum
Other investments | $	$ 5,000		$ 5,000
Municipal securities | General Obligation Bonds | Aggregate Fair Value Exceeding 5 Million
Number of states holding investments	7		7
Municipal securities | Revenue Bonds
Number of issuers	181		165
Other investments | $	$ 617,200		$ 575,000
Number of states holding investments	29		25
Municipal securities | Revenue Bonds | Minimum
Other investments | $	$ 5,000		$ 5,000
Municipal securities | Revenue Bonds | Aggregate Fair Value Exceeding 5 Million
Number of states holding investments	12		13