Note 9 - Allowance for Loan Losses and Credit Quality Information - Classified and Unclassified Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Loans receivable	$ 598,783	$ 594,798
Classified [Member]
Loans receivable	38,555	36,669
Classified [Member] | Special Mention [Member]
Loans receivable	17,257	20,015
Classified [Member] | Substandard [Member]
Loans receivable	21,099	16,361
Classified [Member] | Doubtful [Member]
Loans receivable	94	163
Classified [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans receivable	105	130
Unclassified [Member]
Loans receivable	560,228	558,129
Residential Portfolio Segment [Member]
Loans receivable	107,203	107,005
Residential Portfolio Segment [Member] | Classified [Member]
Loans receivable	2,212	2,275
Residential Portfolio Segment [Member] | Classified [Member] | Special Mention [Member]
Loans receivable	108	77
Residential Portfolio Segment [Member] | Classified [Member] | Substandard [Member]
Loans receivable	2,061	2,154
Residential Portfolio Segment [Member] | Classified [Member] | Doubtful [Member]
Loans receivable	43	44
Residential Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans receivable	0	0
Residential Portfolio Segment [Member] | Unclassified [Member]
Loans receivable	104,991	104,730
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	338,160	334,117
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Loans receivable	188,751	175,177
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Loans receivable	149,409	158,940
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Real Estate Loan [Member]
Loans receivable	12,126	8,835
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Commercial Real Estate Other [Member]
Loans receivable	10,519	13,392
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Special Mention [Member] | Real Estate Loan [Member]
Loans receivable	7,031	5,022
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Special Mention [Member] | Commercial Real Estate Other [Member]
Loans receivable	1,768	9,135
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Substandard [Member] | Real Estate Loan [Member]
Loans receivable	5,095	3,813
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Substandard [Member] | Commercial Real Estate Other [Member]
Loans receivable	8,751	4,257
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Doubtful [Member] | Real Estate Loan [Member]
Loans receivable	0	0
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Doubtful [Member] | Commercial Real Estate Other [Member]
Loans receivable	0	0
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member] | Real Estate Loan [Member]
Loans receivable	0	0
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member] | Commercial Real Estate Other [Member]
Loans receivable	0	0
Commercial Real Estate Portfolio Segment [Member] | Unclassified [Member] | Real Estate Loan [Member]
Loans receivable	176,625	166,342
Commercial Real Estate Portfolio Segment [Member] | Unclassified [Member] | Commercial Real Estate Other [Member]
Loans receivable	138,890	145,548
Consumer Portfolio Segment [Member]
Loans receivable	72,290	73,767
Consumer Portfolio Segment [Member] | Classified [Member]
Loans receivable	984	880
Consumer Portfolio Segment [Member] | Classified [Member] | Special Mention [Member]
Loans receivable	0	0
Consumer Portfolio Segment [Member] | Classified [Member] | Substandard [Member]
Loans receivable	828	631
Consumer Portfolio Segment [Member] | Classified [Member] | Doubtful [Member]
Loans receivable	51	119
Consumer Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans receivable	105	130
Consumer Portfolio Segment [Member] | Unclassified [Member]
Loans receivable	71,306	72,887
Commercial Portfolio Segment [Member]
Loans receivable	81,130	79,909
Commercial Portfolio Segment [Member] | Classified [Member]
Loans receivable	12,714	11,287
Commercial Portfolio Segment [Member] | Classified [Member] | Special Mention [Member]
Loans receivable	8,350	5,781
Commercial Portfolio Segment [Member] | Classified [Member] | Substandard [Member]
Loans receivable	4,364	5,506
Commercial Portfolio Segment [Member] | Classified [Member] | Doubtful [Member]
Loans receivable	0	0
Commercial Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans receivable	0	0
Commercial Portfolio Segment [Member] | Unclassified [Member]
Loans receivable	$ 68,416	$ 68,622