Note 9 - Allowance for Loan Losses and Credit Quality Information - Non-accrual Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Non-accrual loans	$ 3,389	$ 3,273
Residential Portfolio Segment [Member]
Non-accrual loans	1,070	916
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Non-accrual loans	296	41
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Non-accrual loans	1,376	1,343
Consumer Portfolio Segment [Member]
Non-accrual loans	465	630
Commercial Portfolio Segment [Member] | Commercial Business Other [Member]
Non-accrual loans	$ 182	$ 343