Note 8 - Retail Loans by Credit Quality (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	$ 890,113	$ 820,419
Total Retail Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	146,699	149,310
Performing Financial Instruments [Member] | Total Retail Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	145,331	147,998
Nonperforming Financial Instruments [Member] | Total Retail Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	1,368	1,312
Retail Portfolio Segment [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	5,490	6,530
Retail Portfolio Segment [Member] | Family Residential Mortgages [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	76,020	69,469
Retail Portfolio Segment [Member] | Home Equity Loans and Lines [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	65,189	73,311
Retail Portfolio Segment [Member] | Performing Financial Instruments [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	5,342	6,391
Retail Portfolio Segment [Member] | Performing Financial Instruments [Member] | Family Residential Mortgages [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	75,525	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	64,464	72,774
Retail Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Consumer Loans [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	148	139
Retail Portfolio Segment [Member] | Nonperforming Financial Instruments [Member] | Family Residential Mortgages [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and leases receivable	495	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	$ 725	$ 537