Note 9 - Allowance for Loan Losses and Credit Quality Information - Classified and Unclassified Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Loans and leases receivable, gross carrying amount	$ 599,822	$ 560,794
Classified [Member]
Loans and leases receivable, gross carrying amount	44,138	28,177
Classified [Member] | Special Mention [Member]
Loans and leases receivable, gross carrying amount	26,906	7,709
Classified [Member] | Substandard [Member]
Loans and leases receivable, gross carrying amount	17,006	19,985
Classified [Member] | Doubtful [Member]
Loans and leases receivable, gross carrying amount	80	184
Classified [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans and leases receivable, gross carrying amount	146	299
Unclassified [Member]
Loans and leases receivable, gross carrying amount	555,684	532,617
Residential Portfolio Segment [Member]
Loans and leases receivable, gross carrying amount	108,312	103,255
Residential Portfolio Segment [Member] | Classified [Member]
Loans and leases receivable, gross carrying amount	2,658	2,661
Residential Portfolio Segment [Member] | Classified [Member] | Special Mention [Member]
Loans and leases receivable, gross carrying amount	525	457
Residential Portfolio Segment [Member] | Classified [Member] | Substandard [Member]
Loans and leases receivable, gross carrying amount	2,087	2,130
Residential Portfolio Segment [Member] | Classified [Member] | Doubtful [Member]
Loans and leases receivable, gross carrying amount	46	74
Residential Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans and leases receivable, gross carrying amount	0	0
Residential Portfolio Segment [Member] | Unclassified [Member]
Loans and leases receivable, gross carrying amount	105,654	100,594
Commercial Real Estate Portfolio Segment [Member]
Loans and leases receivable, gross carrying amount	324,600	299,080
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Loans and leases receivable, gross carrying amount	175,923	153,343
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member]
Loans and leases receivable, gross carrying amount	148,677	145,737
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Real Estate Loan [Member]
Loans and leases receivable, gross carrying amount	11,314	4,733
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Commercial Real Estate Other [Member]
Loans and leases receivable, gross carrying amount	16,276	8,889
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Special Mention [Member] | Real Estate Loan [Member]
Loans and leases receivable, gross carrying amount	9,098	1,577
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Special Mention [Member] | Commercial Real Estate Other [Member]
Loans and leases receivable, gross carrying amount	9,058	1,702
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Substandard [Member] | Real Estate Loan [Member]
Loans and leases receivable, gross carrying amount	2,216	3,156
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Substandard [Member] | Commercial Real Estate Other [Member]
Loans and leases receivable, gross carrying amount	7,218	7,187
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Doubtful [Member] | Real Estate Loan [Member]
Loans and leases receivable, gross carrying amount	0	0
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Doubtful [Member] | Commercial Real Estate Other [Member]
Loans and leases receivable, gross carrying amount	0	0
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member] | Real Estate Loan [Member]
Loans and leases receivable, gross carrying amount	0	0
Commercial Real Estate Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member] | Commercial Real Estate Other [Member]
Loans and leases receivable, gross carrying amount	0	0
Commercial Real Estate Portfolio Segment [Member] | Unclassified [Member] | Real Estate Loan [Member]
Loans and leases receivable, gross carrying amount	164,609	148,610
Commercial Real Estate Portfolio Segment [Member] | Unclassified [Member] | Commercial Real Estate Other [Member]
Loans and leases receivable, gross carrying amount	132,401	136,848
Consumer Portfolio Segment [Member]
Loans and leases receivable, gross carrying amount	74,560	73,283
Consumer Portfolio Segment [Member] | Classified [Member]
Loans and leases receivable, gross carrying amount	825	940
Consumer Portfolio Segment [Member] | Classified [Member] | Special Mention [Member]
Loans and leases receivable, gross carrying amount	0	0
Consumer Portfolio Segment [Member] | Classified [Member] | Substandard [Member]
Loans and leases receivable, gross carrying amount	645	531
Consumer Portfolio Segment [Member] | Classified [Member] | Doubtful [Member]
Loans and leases receivable, gross carrying amount	34	110
Consumer Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member]
Loans and leases receivable, gross carrying amount	146	299
Consumer Portfolio Segment [Member] | Unclassified [Member]
Loans and leases receivable, gross carrying amount	73,735	72,343
Commercial Portfolio Segment [Member]
Loans and leases receivable, gross carrying amount	92,350	85,176
Commercial Portfolio Segment [Member] | Transportation Industry Loans [Member]
Loans and leases receivable, gross carrying amount	9,872	10,509
Commercial Portfolio Segment [Member] | Commercial Business Other [Member]
Loans and leases receivable, gross carrying amount	82,478	74,667
Commercial Portfolio Segment [Member] | Classified [Member] | Transportation Industry Loans [Member]
Loans and leases receivable, gross carrying amount	1,053	4,065
Commercial Portfolio Segment [Member] | Classified [Member] | Commercial Business Other [Member]
Loans and leases receivable, gross carrying amount	12,012	6,889
Commercial Portfolio Segment [Member] | Classified [Member] | Special Mention [Member] | Transportation Industry Loans [Member]
Loans and leases receivable, gross carrying amount	0	0
Commercial Portfolio Segment [Member] | Classified [Member] | Special Mention [Member] | Commercial Business Other [Member]
Loans and leases receivable, gross carrying amount	8,225	3,973
Commercial Portfolio Segment [Member] | Classified [Member] | Substandard [Member] | Transportation Industry Loans [Member]
Loans and leases receivable, gross carrying amount	1,053	4,065
Commercial Portfolio Segment [Member] | Classified [Member] | Substandard [Member] | Commercial Business Other [Member]
Loans and leases receivable, gross carrying amount	3,787	2,916
Commercial Portfolio Segment [Member] | Classified [Member] | Doubtful [Member] | Transportation Industry Loans [Member]
Loans and leases receivable, gross carrying amount	0	0
Commercial Portfolio Segment [Member] | Classified [Member] | Doubtful [Member] | Commercial Business Other [Member]
Loans and leases receivable, gross carrying amount	0	0
Commercial Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member] | Transportation Industry Loans [Member]
Loans and leases receivable, gross carrying amount	0	0
Commercial Portfolio Segment [Member] | Classified [Member] | Unlikely to be Collected Financing Receivable [Member] | Commercial Business Other [Member]
Loans and leases receivable, gross carrying amount	0	0
Commercial Portfolio Segment [Member] | Unclassified [Member] | Transportation Industry Loans [Member]
Loans and leases receivable, gross carrying amount	8,819	6,444
Commercial Portfolio Segment [Member] | Unclassified [Member] | Commercial Business Other [Member]
Loans and leases receivable, gross carrying amount	$ 70,466	$ 67,778