Note 1 - Significant Accounting Policies (Details Textual)	3 Months Ended
	Mar. 31, 2023 USD ($) shares	Mar. 31, 2022 USD ($) shares	Dec. 31, 2022 USD ($)	Jan. 01, 2022 USD ($)	Dec. 31, 2021 USD ($)
Number of Unconsolidated Business Trusts Formed to Issue Trust Preferred Securities	5
Debt Securities, Available-for-Sale, Allowance for Credit Loss			$ 0
Financing Receivable, Unamortized Loan Cost (Fee)	$ (1,400,000)		(1,000,000.0)
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	$ 3,900,000		3,600,000
Financing Receivable, Credit Loss, Expense (Reversal)	600,000	$ 100,000
Allowance for Doubtful Accounts Receivable, Estimated Maximum Forecast, Increase in Allowance	100,000
Financing Receivable, Allowance for Credit Loss, Ending Balance	42,877,000	$ 35,153,000	42,246,000		$ 35,363,000
Retained Earnings (Accumulated Deficit), Total	232,123,000		216,313,000
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	100,000
Continuing Involvement with Transferred Financial Assets, Principal Amount Outstanding	$ 1,370,000,000		$ 1,380,000,000
Core Deposits [Member]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (Year)	10 years
Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Allowance for Credit Loss, Ending Balance				$ (400,000)	$ (400,000)
Retained Earnings (Accumulated Deficit), Total				300,000
Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member] | Other Assets [Member]
Deferred Income Tax Assets, Net				$ 100,000
Restricted Stock [Member]
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights (in shares) | shares	360,000	335,000
Share-Based Payment Arrangement, Option [Member]
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights (in shares) | shares		8,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares) | shares	5,000