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Note 3 - Loans and Allowance for Credit Losses (Details Textual)	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	Jan. 01, 2022 USD ($)	Dec. 31, 2021 USD ($)
Financing Receivable, before Allowance for Credit Loss		$ 4,104,376,000		$ 3,916,619,000
Increase (Decrease) in Finance Receivables		$ 188,000,000
Loans and Leases Receivable, Percentage Period Increase (Decrease)		4.80%
Financing Receivable, Nonaccrual, Interest Income		$ 0		0
Financing Receivable, Revolving, Converted to Term Loan		0		0
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts	0		0
Financing Receivable, Troubled Debt Restructuring		8,184,000
Collateral Dependent Loans [Member]
Financing Receivable, before Allowance for Credit Loss		5,900,000		7,700,000
Commercial Real Estate Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member] | Reclassification Between Loan Segments [Member]
Increase (Decrease) in Finance Receivables				54,500,000
Commercial Real Estate Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member] | Reclassification Between Loan Segments [Member]
Increase (Decrease) in Finance Receivables				(54,500,000)
Retail Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss		885,545,000		784,789,000
Financing Receivable, Troubled Debt Restructuring		0
Retail Portfolio Segment [Member] | Other Consumer Loans [Member]
Financing Receivable, before Allowance for Credit Loss		31,370,000		29,753,000
Financing Receivable, Troubled Debt Restructuring	$ 2,000	0	$ 2,000		$ 3,000		$ 1,202,000
Retail Portfolio Segment [Member] | Other Consumer Loans [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Troubled Debt Restructuring						$ (1,200,000)
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
Financing Receivable, before Allowance for Credit Loss		854,175,000		$ 755,036,000
Financing Receivable, Troubled Debt Restructuring	$ 2,544,000	$ 0	$ 2,544,000		$ 2,339,000		$ 627,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member]
Financing Receivable, Troubled Debt Restructuring						$ 1,200,000

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