Note 4 - Loans and Related Allowance for Loan Loss - Activity in the Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Balance	$ 8,083	$ 7,191	$ 7,803	$ 6,490
Charge-offs	(284)	(208)	(924)	(765)
Recoveries	57	33	257	141
Provision	300	450	1,020	1,600
Balance	8,156	7,466	8,156	7,466
Individually Evaluated for Impairment	1,038	1,247	1,038	1,247	$ 1,160
Collectively Evaluated for Potential Impairment	7,118	6,219	7,118	6,219	6,643
Residential Portfolio Segment [Member] | Real Estate Sector [Member]
Balance	940	1,110	1,106	1,623
Charge-offs	(67)	(12)	(131)	(48)
Recoveries	17	6	60	15
Provision	(13)	(32)	(158)	(518)
Balance	877	1,072	877	1,072
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment	877	1,072	877	1,072	1,106
Commercial Portfolio Segment [Member] | Real Estate Sector [Member]
Balance	2,630	1,967	2,307	2,045
Charge-offs		(11)	(132)	(191)
Recoveries	1		2	2
Provision	59	66	513	166
Balance	2,690	2,022	2,690	2,022
Individually Evaluated for Impairment	392	507	392	507	474
Collectively Evaluated for Potential Impairment	2,298	1,515	2,298	1,515	1,833
Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Balance	1,869	1,583	1,699	784
Charge-offs
Recoveries	1		37
Provision	(162)	70	(28)	869
Balance	1,708	1,653	1,708	1,653
Individually Evaluated for Impairment	646	740	646	740	686
Collectively Evaluated for Potential Impairment	1,062	913	1,062	913	1,013
Construction Portfolio Segment [Member] | Real Estate Sector [Member]
Balance	142	82	65	137
Charge-offs
Recoveries
Provision	85	(20)	162	(75)
Balance	227	62	227	62
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment	227	62	227	62	65
Consumer Portfolio Segment [Member]
Balance	2,223	2,143	2,463	1,887
Charge-offs	(217)	(166)	(661)	(483)
Recoveries	38	22	158	108
Provision	317	359	401	846
Balance	2,361	2,358	2,361	2,358
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment	2,361	2,358	2,361	2,358	2,463
Other Portfolio Segment [Member]
Balance		1
Charge-offs		(19)		(43)
Recoveries		5		16
Provision		14		28
Balance		1		1
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment		1		1
Unallocated Financing Receivables [Member]
Balance	279	305	163	14
Charge-offs
Recoveries
Provision	14	(7)	130	284
Balance	293	298	293	298
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment	293	298	293	298	163
Originated Loans [Member]
Balance	7,467	7,055	7,283	6,490
Charge-offs	(239)	(198)	(683)	(554)
Recoveries	45	30	203	126
Provision	300	441	770	1,266
Balance	7,573	7,328	7,573	7,328
Individually Evaluated for Impairment	1,028	1,086	1,028	1,086	1,015
Collectively Evaluated for Potential Impairment	6,545	6,242	6,545	6,242	6,268
Originated Loans [Member] | Residential Portfolio Segment [Member] | Real Estate Sector [Member]
Balance	940	1,110	1,106	1,623
Charge-offs	(22)	(4)	(22)	(24)
Recoveries	6	4	11	8
Provision	(47)	(38)	(218)	(535)
Balance	877	1,072	877	1,072
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment	877	1,072	877	1,072	1,106
Originated Loans [Member] | Commercial Portfolio Segment [Member] | Real Estate Sector [Member]
Balance	2,017	1,956	1,942	2,045
Charge-offs		(11)		(11)
Recoveries
Provision	64	77	139	(12)
Balance	2,081	2,022	2,081	2,022
Individually Evaluated for Impairment	392	385	392	385	360
Collectively Evaluated for Potential Impairment	1,689	1,637	1,689	1,637	1,582
Originated Loans [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Balance	1,760	1,468	1,579	784
Charge-offs
Recoveries	1		37
Provision	(155)	50	(10)	734
Balance	1,606	1,518	1,606	1,518
Individually Evaluated for Impairment	636	701	636	701	655
Collectively Evaluated for Potential Impairment	970	817	970	817	924
Originated Loans [Member] | Construction Portfolio Segment [Member] | Real Estate Sector [Member]
Balance	142	82	65	137
Charge-offs
Recoveries
Provision	85	(20)	162	(75)
Balance	227	62	227	62
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment	227	62	227	62	65
Originated Loans [Member] | Consumer Portfolio Segment [Member]
Balance	2,223	2,143	2,463	1,887
Charge-offs	(217)	(166)	(661)	(476)
Recoveries	38	21	155	102
Provision	317	360	404	845
Balance	2,361	2,358	2,361	2,358
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment	2,361	2,358	2,361	2,358	2,463
Originated Loans [Member] | Other Portfolio Segment [Member]
Balance		1
Charge-offs		(17)		(43)
Recoveries		5		16
Provision		12		28
Balance		1		1
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment		1		1
Originated Loans [Member] | Unallocated Financing Receivables [Member]
Balance	385	295	128	14
Charge-offs
Recoveries
Provision	36		293	281
Balance	421	295	421	295
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment	421	295	421	295	128
Acquired Loans [Member]
Balance	616	136	520
Charge-offs	(45)	(10)	(241)	(211)
Recoveries	12	3	54	15
Provision		9	250	334
Balance	583	138	583	138
Individually Evaluated for Impairment	10	161	10	161	145
Collectively Evaluated for Potential Impairment	573		573		375
Collectively Evaluated for Potential Impairment		(23)		(23)
Acquired Loans [Member] | Residential Portfolio Segment [Member] | Real Estate Sector [Member]
Balance
Charge-offs	(45)	(8)	(109)	(24)
Recoveries	11	2	49	7
Provision	34	6	60	17
Balance
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment
Collectively Evaluated for Potential Impairment
Acquired Loans [Member] | Commercial Portfolio Segment [Member] | Real Estate Sector [Member]
Balance	613	11	365
Charge-offs			(132)	(180)
Recoveries	1		2	2
Provision	(5)	(11)	374	178
Balance	609		609
Individually Evaluated for Impairment		122		122	114
Collectively Evaluated for Potential Impairment	609		609		251
Collectively Evaluated for Potential Impairment		(122)		(122)
Acquired Loans [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial Sector [Member]
Balance	109	115	120
Charge-offs
Recoveries
Provision	(7)	20	(18)	135
Balance	102	135	102	135
Individually Evaluated for Impairment	10	39	10	39	31
Collectively Evaluated for Potential Impairment	92		92		89
Collectively Evaluated for Potential Impairment		96		96
Acquired Loans [Member] | Construction Portfolio Segment [Member] | Real Estate Sector [Member]
Balance
Charge-offs
Recoveries
Provision
Balance
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment
Collectively Evaluated for Potential Impairment
Acquired Loans [Member] | Consumer Portfolio Segment [Member]
Balance
Charge-offs				(7)
Recoveries		1	3	6
Provision		(1)	(3)	1
Balance
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment
Collectively Evaluated for Potential Impairment
Acquired Loans [Member] | Other Portfolio Segment [Member]
Balance
Charge-offs		(2)
Recoveries
Provision		2
Balance
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment
Collectively Evaluated for Potential Impairment
Acquired Loans [Member] | Unallocated Financing Receivables [Member]
Balance	(106)	10	35
Charge-offs
Recoveries
Provision	(22)	(7)	(163)	3
Balance	(128)	3	(128)	3
Individually Evaluated for Impairment
Collectively Evaluated for Potential Impairment	$ (128)		$ (128)		$ 35
Collectively Evaluated for Potential Impairment		$ 3		$ 3