Note 4 - Loans Receivable and Related Allowance for Loan Losses - Nonaccrual Loans by Aging Category (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Nonaccrual	$ 3,553	$ 2,654
Financial Asset, Not Past Due [Member]
Nonaccrual	2,703	1,590
Financial Asset, 30 to 59 Days Past Due [Member]
Nonaccrual	77	10
Financial Asset, 60 to 89 Days Past Due [Member]
Nonaccrual	6	69
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Nonaccrual	767	985
Residential Portfolio Segment [Member]
Nonaccrual	730	810
Residential Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Nonaccrual	190	196
Residential Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Nonaccrual	68	0
Residential Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Nonaccrual	0	69
Residential Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Nonaccrual	472	545
Home Equity Loans and Lines of Credit [Member]
Nonaccrual	122	242
Home Equity Loans and Lines of Credit [Member] | Financial Asset, Not Past Due [Member]
Nonaccrual	4	4
Home Equity Loans and Lines of Credit [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Nonaccrual	0	0
Home Equity Loans and Lines of Credit [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Nonaccrual	0	0
Home Equity Loans and Lines of Credit [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Nonaccrual	118	238
Commercial Real Estate Portfolio Segment [Member]
Nonaccrual	2,601	1,250
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Nonaccrual	2,420	1,052
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Nonaccrual	9	10
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Nonaccrual	6	0
Commercial Real Estate Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Nonaccrual	166	188
Commercial Portfolio Segment [Member]
Nonaccrual	89	338
Commercial Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Nonaccrual	89	338
Commercial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Nonaccrual	0	0
Commercial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Nonaccrual	0	0
Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Nonaccrual	0	0
Consumer Portfolio Segment [Member]
Nonaccrual	11	14
Consumer Portfolio Segment [Member] | Financial Asset, Not Past Due [Member]
Nonaccrual	0	0
Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Nonaccrual	0	0
Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Nonaccrual	0	0
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Nonaccrual	$ 11	$ 14