Note 5 - Retail Loans by Credit Quality (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	$ 921,856	$ 820,419
Total Retail Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	152,046	149,310
Performing Financial Instruments [Member] | Total Retail Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	150,553	147,998
Nonperforming Financial Instruments [Member] | Total Retail Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	1,493	1,312
Retail Portfolio Segment [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	5,364	6,530
Retail Portfolio Segment [Member] | Family Residential Mortgages [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	82,739	69,469
Retail Portfolio Segment [Member] | Home Equity Loans and Lines [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	63,943	73,311
Retail Portfolio Segment [Member] | Performing Financial Instruments [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	5,259	6,391
Retail Portfolio Segment [Member] | Performing Financial Instruments [Member] | Family Residential Mortgages [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	82,103	68,833
Retail Portfolio Segment [Member] | Performing Financial Instruments [Member] | Home Equity Loans and Lines [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	63,191	72,774
Retail Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	105	139
Retail Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Family Residential Mortgages [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	636	636
Retail Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Home Equity Loans and Lines [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	$ 752	$ 537