Note 7 - Loans and Related Allowance for Credit Losses (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Financing Receivable, Accrued Interest, after Allowance for Credit Loss	$ 5,300,000		$ 5,300,000			$ 5,500,000
Financing Receivable, Deferred Commitment Fee	8,400,000		8,400,000			9,200,000
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	$ 731,000	$ 395,000	$ 833,000
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease), Percentage	3.40%	1.90%	3.80%
Financing Receivable, before Allowance for Credit Loss, Total	$ 1,504,531,000		$ 1,504,531,000			1,478,130,000
Financing Receivable, Nonaccrual, Interest Income	$ 852,000	$ 211,000	1,200,000	$ 414,000
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts	0
Mortgage Loans in Process of Foreclosure, Amount	$ 381,000		381,000			228,000
Financing Receivable, Allowance for Credit Loss	22,526,000	$ 20,986,000	22,526,000	$ 20,986,000	$ 21,795,000	21,693,000	$ 20,591,000	$ 14,438,000
Threshold For Loans Evaluated For Impairment [Member]
Financing Receivable, before Allowance for Credit Loss, Total	750,000		750,000
Threshold For Loans Evaluated For Impairment [Member] | Criticized Relationships [Member]
Financing Receivable, before Allowance for Credit Loss, Total	150,000		150,000
Unfunded Loan Commitment [Member]
Financing Receivable, Allowance for Credit Loss	$ 1,800,000		$ 1,800,000			$ 1,800,000