Note 9 - Allowance for Loan Losses and Credit Quality Information - Classified and Unclassified Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Loans receivable	$ 594,399	$ 594,798
Classified [Member]
Loans receivable	32,555	36,669
Classified [Member] | Special Mention [Member]
Loans receivable	14,209	20,015
Classified [Member] | Substandard [Member]
Loans receivable	18,134	16,361
Classified [Member] | Doubtful [Member]
Loans receivable	84	163
Classified [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans receivable	128	130
Unclassified [Member]
Loans receivable	561,844	558,129
Residential Portfolio Segment [Member]
Loans receivable	108,493	107,005
Residential Portfolio Segment [Member] | Classified [Member]
Loans receivable	2,418	2,275
Residential Portfolio Segment [Member] | Classified [Member] | Special Mention [Member]
Loans receivable	257	77
Residential Portfolio Segment [Member] | Classified [Member] | Substandard [Member]
Loans receivable	2,119	2,154
Residential Portfolio Segment [Member] | Classified [Member] | Doubtful [Member]
Loans receivable	42	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	106,075	104,730
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	332,503	334,117
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Loans receivable	187,373	175,177
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Loans receivable	145,130	158,940
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Real Estate Loan [Member]
Loans receivable	10,193	8,835
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Commercial Real Estate Other [Member]
Loans receivable	10,431	13,392
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Special Mention [Member] | Real Estate Loan [Member]
Loans receivable	5,312	5,022
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Special Mention [Member] | Commercial Real Estate Other [Member]
Loans receivable	2,896	9,135
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Substandard [Member] | Real Estate Loan [Member]
Loans receivable	4,881	3,813
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Substandard [Member] | Commercial Real Estate Other [Member]
Loans receivable	7,535	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	177,180	166,342
Commercial Real Estate Portfolio Segment [Member] | Unclassified [Member] | Commercial Real Estate Other [Member]
Loans receivable	134,699	145,548
Consumer Portfolio Segment [Member]
Loans receivable	74,521	73,767
Consumer Portfolio Segment [Member] | Classified [Member]
Loans receivable	935	880
Consumer Portfolio Segment [Member] | Classified [Member] | Special Mention [Member]
Loans receivable	0	0
Consumer Portfolio Segment [Member] | Classified [Member] | Substandard [Member]
Loans receivable	765	631
Consumer Portfolio Segment [Member] | Classified [Member] | Doubtful [Member]
Loans receivable	42	119
Consumer Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans receivable	128	130
Consumer Portfolio Segment [Member] | Unclassified [Member]
Loans receivable	73,586	72,887
Commercial Portfolio Segment [Member]
Loans receivable	78,882	79,909
Commercial Portfolio Segment [Member] | Classified [Member]
Loans receivable	8,578	11,287
Commercial Portfolio Segment [Member] | Classified [Member] | Special Mention [Member]
Loans receivable	5,744	5,781
Commercial Portfolio Segment [Member] | Classified [Member] | Substandard [Member]
Loans receivable	2,834	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	$ 70,304	$ 68,622