Note 3 - Loans Receivable and Related Allowance for Loan Losses - Nonaccrual Loans by Aging Category (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Nonaccrual	$ 2,654	$ 3,523
Residential Portfolio Segment [Member]
Nonaccrual	810	1,619
Home Equity Loans and Lines of Credit [Member]
Nonaccrual	242	75
Commercial Real Estate Portfolio Segment [Member]
Nonaccrual	1,250	1,613
Commercial Portfolio Segment [Member]
Nonaccrual	338	168
Consumer Portfolio Segment [Member]
Nonaccrual	14	48
Not Past Due [Member]
Nonaccrual	1,590	1,408
Not Past Due [Member] | Residential Portfolio Segment [Member]
Nonaccrual	196	220
Not Past Due [Member] | Home Equity Loans and Lines of Credit [Member]
Nonaccrual	4	4
Not Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Nonaccrual	1,052	1,016
Not Past Due [Member] | Commercial Portfolio Segment [Member]
Nonaccrual	338	168
Not Past Due [Member] | Consumer Portfolio Segment [Member]
Nonaccrual	0	0
Financial Asset, 30 to 59 Days Past Due [Member]
Nonaccrual	10	70
Financial Asset, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member]
Nonaccrual	0	70
Financial Asset, 30 to 59 Days Past Due [Member] | Home Equity Loans and Lines of Credit [Member]
Nonaccrual	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Nonaccrual	10	0
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Nonaccrual	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Nonaccrual	0	0
Financial Asset, 60 to 89 Days Past Due [Member]
Nonaccrual	69	24
Financial Asset, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member]
Nonaccrual	69	0
Financial Asset, 60 to 89 Days Past Due [Member] | Home Equity Loans and Lines of Credit [Member]
Nonaccrual	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Nonaccrual	0	24
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Nonaccrual	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Nonaccrual	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Nonaccrual	985	2,021
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member]
Nonaccrual	545	1,329
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Home Equity Loans and Lines of Credit [Member]
Nonaccrual	238	71
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Nonaccrual	188	573
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Nonaccrual	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Nonaccrual	$ 14	$ 48