Note 8 - Modified Loans by Major Loan Class and Total Deferral by Number of Months (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accounts Notes And Loans Receivable [Line Items]
Total Modified Loans	$ 5,083	$ 5,312
COVID-19 Pandemic [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Modified Loans	232
COVID-19 Pandemic [Member] | Total Number of Months Deferred 4-6 Months [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Modified Loans	228
COVID-19 Pandemic [Member] | Total Number of Months Deferred 10-12 Months [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Modified Loans	4
COVID-19 Pandemic [Member] | Retail Portfolio Segment [Member] | Consumer Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Modified Loans	4
COVID-19 Pandemic [Member] | Retail Portfolio Segment [Member] | Family Residential Mortgages [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Modified Loans	228
COVID-19 Pandemic [Member] | Retail Portfolio Segment [Member] | Total Number of Months Deferred 4-6 Months [Member] | Family Residential Mortgages [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Modified Loans	228
COVID-19 Pandemic [Member] | Retail Portfolio Segment [Member] | Total Number of Months Deferred 10-12 Months [Member] | Consumer Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Modified Loans	$ 4