Note 1 - Summary of Significant Accounting Policies (Details Textual) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023 USD ($) shares	Sep. 30, 2022 USD ($) shares	Sep. 30, 2023 USD ($) shares	Sep. 30, 2022 USD ($) shares	Dec. 31, 2022 USD ($)
Number of Unconsolidated Business Trusts Formed to Issue Trust Preferred Securities	5		5
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Ending Balance	$ 0		$ 0		$ 0
Financing Receivable, Unamortized Loan Cost (Fee)	$ 2,400		2,400		1,000
Interest Income on Commercial and Mortgage Loans Discontinued Period (Day)	90 days
Maximum Delinquency Period for Consumer and Credit Card Loans to be Charged Off (Day)	120 days
Loan, Mortgage, Held-for-Sale, Fair Value Disclosure	$ 10,200		10,200		3,600
Financing Receivable, Credit Loss, Expense (Reversal)	3,300	$ 2,900	5,900	$ 3,500
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)			(900)
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)			(100)
Continuing Involvement with Transferred Financial Assets, Principal Amount Outstanding	$ 1,390,000		$ 1,390,000		1,380,000
Goodwill, Impairment Loss					$ 0
Core Deposits [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (Year)	10 years
Restricted Stock [Member]
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights (in shares) | shares	345,000	319,000	345,000	319,000
Share-Based Payment Arrangement, Option [Member]
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights (in shares) | shares		1,000		1,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares	5,000	5,000	5,000	5,000