Note 3 - Loans and Allowance for Credit Losses - Age Analysis of Past Due Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, before Allowance for Credit Loss	$ 4,322,006	$ 4,303,758
Recorded Balance 89 Days and Accruing	0	0
Commercial Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	3,429,642	3,415,299
Recorded Balance 89 Days and Accruing	0	0
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, before Allowance for Credit Loss	1,222,637	1,254,586
Recorded Balance 89 Days and Accruing	0	0
Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Financing Receivable, before Allowance for Credit Loss	75,091	74,753
Recorded Balance 89 Days and Accruing	0	0
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Financing Receivable, before Allowance for Credit Loss	719,338	717,667
Recorded Balance 89 Days and Accruing	0	0
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Financing Receivable, before Allowance for Credit Loss	1,045,615	1,035,684
Recorded Balance 89 Days and Accruing	0	0
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Financing Receivable, before Allowance for Credit Loss	366,961	332,609
Recorded Balance 89 Days and Accruing	0	0
Retail Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	892,364	888,459
Recorded Balance 89 Days and Accruing	0	0
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Financing Receivable, before Allowance for Credit Loss	840,653	837,406
Recorded Balance 89 Days and Accruing	0	0
Retail Portfolio Segment [Member] | Other Consumer Loans [Member]
Financing Receivable, before Allowance for Credit Loss	51,711	51,053
Recorded Balance 89 Days and Accruing	0	0
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, before Allowance for Credit Loss	561	1,035
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	16	4
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, before Allowance for Credit Loss	16	4
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	545	1,031
Financial Asset, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Financing Receivable, before Allowance for Credit Loss	508	934
Financial Asset, 30 to 59 Days Past Due [Member] | Retail Portfolio Segment [Member] | Other Consumer Loans [Member]
Financing Receivable, before Allowance for Credit Loss	37	97
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, before Allowance for Credit Loss	71	145
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	71	145
Financial Asset, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Financing Receivable, before Allowance for Credit Loss	71	145
Financial Asset, 60 to 89 Days Past Due [Member] | Retail Portfolio Segment [Member] | Other Consumer Loans [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, before Allowance for Credit Loss	441	357
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	249	319
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, before Allowance for Credit Loss	249	249
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	70
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	192	38
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Financing Receivable, before Allowance for Credit Loss	165	38
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Retail Portfolio Segment [Member] | Other Consumer Loans [Member]
Financing Receivable, before Allowance for Credit Loss	27	0
Financial Asset, Past Due [Member]
Financing Receivable, before Allowance for Credit Loss	1,073	1,537
Financial Asset, Past Due [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	265	323
Financial Asset, Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, before Allowance for Credit Loss	265	253
Financial Asset, Past Due [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	70
Financial Asset, Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Financing Receivable, before Allowance for Credit Loss	0	0
Financial Asset, Past Due [Member] | Retail Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	808	1,214
Financial Asset, Past Due [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Financing Receivable, before Allowance for Credit Loss	744	1,117
Financial Asset, Past Due [Member] | Retail Portfolio Segment [Member] | Other Consumer Loans [Member]
Financing Receivable, before Allowance for Credit Loss	64	97
Financial Asset, Not Past Due [Member]
Financing Receivable, before Allowance for Credit Loss	4,320,933	4,302,221
Financial Asset, Not Past Due [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	3,429,377	3,414,976
Financial Asset, Not Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Financing Receivable, before Allowance for Credit Loss	1,222,372	1,254,333
Financial Asset, Not Past Due [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Financing Receivable, before Allowance for Credit Loss	75,091	74,753
Financial Asset, Not Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
Financing Receivable, before Allowance for Credit Loss	719,338	717,597
Financial Asset, Not Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
Financing Receivable, before Allowance for Credit Loss	1,045,615	1,035,684
Financial Asset, Not Past Due [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Financing Receivable, before Allowance for Credit Loss	366,961	332,609
Financial Asset, Not Past Due [Member] | Retail Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	891,556	887,245
Financial Asset, Not Past Due [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Financing Receivable, before Allowance for Credit Loss	839,909	836,289
Financial Asset, Not Past Due [Member] | Retail Portfolio Segment [Member] | Other Consumer Loans [Member]
Financing Receivable, before Allowance for Credit Loss	$ 51,647	$ 50,956