Note 9 - Allowance for Loan Losses and Credit Quality Information - Classified and Unclassified Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Loans receivable	$ 591,855	$ 560,794
Classified [Member]
Loans receivable	34,653	28,177
Classified [Member] | Special Mention [Member]
Loans receivable	17,456	7,709
Classified [Member] | Substandard [Member]
Loans receivable	16,888	19,985
Classified [Member] | Doubtful [Member]
Loans receivable	165	184
Classified [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans receivable	144	299
Unclassified [Member]
Loans receivable	557,202	532,617
Residential Portfolio Segment [Member]
Loans receivable	107,312	103,255
Residential Portfolio Segment [Member] | Classified [Member]
Loans receivable	2,345	2,661
Residential Portfolio Segment [Member] | Classified [Member] | Special Mention [Member]
Loans receivable	277	457
Residential Portfolio Segment [Member] | Classified [Member] | Substandard [Member]
Loans receivable	2,023	2,130
Residential Portfolio Segment [Member] | Classified [Member] | Doubtful [Member]
Loans receivable	45	74
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	104,967	100,594
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	329,251	299,080
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Loans receivable	175,785	153,343
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Loans receivable	153,466	145,737
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Real Estate Loan [Member]
Loans receivable	4,388	4,733
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Commercial Real Estate Other [Member]
Loans receivable	17,307	8,889
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Special Mention [Member] | Real Estate Loan [Member]
Loans receivable	1,735	1,577
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Special Mention [Member] | Commercial Real Estate Other [Member]
Loans receivable	9,897	1,702
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Substandard [Member] | Real Estate Loan [Member]
Loans receivable	2,653	3,156
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Substandard [Member] | Commercial Real Estate Other [Member]
Loans receivable	7,410	7,187
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	171,397	148,610
Commercial Real Estate Portfolio Segment [Member] | Unclassified [Member] | Commercial Real Estate Other [Member]
Loans receivable	136,159	136,848
Consumer Portfolio Segment [Member]
Loans receivable	74,984	73,283
Consumer Portfolio Segment [Member] | Classified [Member]
Loans receivable	925	940
Consumer Portfolio Segment [Member] | Classified [Member] | Special Mention [Member]
Loans receivable	0	0
Consumer Portfolio Segment [Member] | Classified [Member] | Substandard [Member]
Loans receivable	661	531
Consumer Portfolio Segment [Member] | Classified [Member] | Doubtful [Member]
Loans receivable	120	110
Consumer Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans receivable	144	299
Consumer Portfolio Segment [Member] | Unclassified [Member]
Loans receivable	74,059	72,343
Commercial Portfolio Segment [Member]
Loans receivable	80,308	85,176
Commercial Portfolio Segment [Member] | Transportation Industry Loans [Member]
Loans receivable	9,418	10,509
Commercial Portfolio Segment [Member] | Commercial Business Other [Member]
Loans receivable	70,890	74,667
Commercial Portfolio Segment [Member] | Classified [Member] | Transportation Industry Loans [Member]
Loans receivable	1,128	4,065
Commercial Portfolio Segment [Member] | Classified [Member] | Commercial Business Other [Member]
Loans receivable	8,560	6,889
Commercial Portfolio Segment [Member] | Classified [Member] | Special Mention [Member] | Transportation Industry Loans [Member]
Loans receivable	0	0
Commercial Portfolio Segment [Member] | Classified [Member] | Special Mention [Member] | Commercial Business Other [Member]
Loans receivable	5,547	3,973
Commercial Portfolio Segment [Member] | Classified [Member] | Substandard [Member] | Transportation Industry Loans [Member]
Loans receivable	1,128	4,065
Commercial Portfolio Segment [Member] | Classified [Member] | Substandard [Member] | Commercial Business Other [Member]
Loans receivable	3,013	2,916
Commercial Portfolio Segment [Member] | Classified [Member] | Doubtful [Member] | Transportation Industry Loans [Member]
Loans receivable	0	0
Commercial Portfolio Segment [Member] | Classified [Member] | Doubtful [Member] | Commercial Business Other [Member]
Loans receivable	0	0
Commercial Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member] | Transportation Industry Loans [Member]
Loans receivable	0	0
Commercial Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member] | Commercial Business Other [Member]
Loans receivable	0	0
Commercial Portfolio Segment [Member] | Unclassified [Member] | Transportation Industry Loans [Member]
Loans receivable	8,290	6,444
Commercial Portfolio Segment [Member] | Unclassified [Member] | Commercial Business Other [Member]
Loans receivable	$ 62,330	$ 67,778