Note 9 - Allowance for Loan Losses and Credit Quality Information - Non-accrual Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Non-accrual loans	$ 2,541	$ 2,081
Residential Portfolio Segment [Member]
Non-accrual loans	352	617
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Non-accrual loans	1,138	184
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Non-accrual loans	399	0
Consumer Portfolio Segment [Member]
Non-accrual loans	641	659
Commercial Portfolio Segment [Member]
Non-accrual loans	$ 11	$ 621