Note 3 - Loans Receivable and Related Allowance for Loan Losses - Nonaccrual Loans by Aging Category (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Nonaccrual	$ 2,237	$ 3,003
Residential Portfolio Segment [Member]
Nonaccrual	855	856
Home Equity Loans and Lines of Credit [Member]
Nonaccrual	487	526
Commercial Real Estate Portfolio Segment [Member]
Nonaccrual	606	964
Commercial Portfolio Segment [Member]
Nonaccrual	174	584
Consumer Portfolio Segment [Member]
Nonaccrual	115	73
Not Past Due [Member]
Nonaccrual	452	1,284
Not Past Due [Member] | Residential Portfolio Segment [Member]
Nonaccrual	335	366
Not Past Due [Member] | Home Equity Loans and Lines of Credit [Member]
Nonaccrual	6	8
Not Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Nonaccrual	111	341
Not Past Due [Member] | Commercial Portfolio Segment [Member]
Nonaccrual		569
Not Past Due [Member] | Consumer Portfolio Segment [Member]
Nonaccrual
Financing Receivables, 30 to 59 Days Past Due [Member]
Nonaccrual	265
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member]
Nonaccrual
Financing Receivables, 30 to 59 Days Past Due [Member] | Home Equity Loans and Lines of Credit [Member]
Nonaccrual
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Nonaccrual	265
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Nonaccrual
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Nonaccrual
Financing Receivables, 60 to 89 Days Past Due [Member]
Nonaccrual	113	75
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member]
Nonaccrual	74	75
Financing Receivables, 60 to 89 Days Past Due [Member] | Home Equity Loans and Lines of Credit [Member]
Nonaccrual
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Nonaccrual
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Nonaccrual	39
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Nonaccrual
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Nonaccrual	1,407	1,644
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member]
Nonaccrual	446	415
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Home Equity Loans and Lines of Credit [Member]
Nonaccrual	481	518
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Nonaccrual	230	623
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Nonaccrual	135	15
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Nonaccrual	$ 115	$ 73