Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Loans and Allowance for Loan Losses by Evaluation Method (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Allowance for loan losses, individually evaluated for impairment	$ 169	$ 177
Allowance for loan losses, collectively evaluated for impairment	7,222	7,748
Allowance for loan losses	7,391	7,925	$ 8,261	$ 8,300
Loans, individually evaluated for impairment	11,681	11,924
Loans, collectively evaluated for impairment	647,571	656,758
Loans	659,252	668,682
Real Estate Construction Portfolio Segment[Member]
Allowance for loan losses, individually evaluated for impairment	0	0
Allowance for loan losses, collectively evaluated for impairment	295	337
Allowance for loan losses	295	337	377	438
Loans, individually evaluated for impairment	2,817	2,882
Loans, collectively evaluated for impairment	29,264	31,812
Loans	32,081	34,694
Consumer Real Estate Portfolio Segment [Member]
Allowance for loan losses, individually evaluated for impairment	15	16
Allowance for loan losses, collectively evaluated for impairment	1,914	2,011
Allowance for loan losses	1,929	2,027	1,746	1,830
Loans, individually evaluated for impairment	1,155	1,267
Loans, collectively evaluated for impairment	166,273	165,698
Loans	167,428	166,965
Commercial Real Estate Portfolio Segment [Member]
Allowance for loan losses, individually evaluated for impairment	0	0
Allowance for loan losses, collectively evaluated for impairment	2,790	3,044
Allowance for loan losses	2,790	3,044	3,617	3,738
Loans, individually evaluated for impairment	6,479	6,516
Loans, collectively evaluated for impairment	326,886	333,898
Loans	333,365	340,414
Commercial Non Real Estate Segment [Member]
Allowance for loan losses, individually evaluated for impairment	153	160
Allowance for loan losses, collectively evaluated for impairment	763	912
Allowance for loan losses	916	1,072	1,142	1,063
Loans, individually evaluated for impairment	1,203	1,229
Loans, collectively evaluated for impairment	40,873	39,289
Loans	42,076	40,518
Public Sector and IDA Portfolio Segment[Member]
Allowance for loan losses, individually evaluated for impairment	0	0
Allowance for loan losses, collectively evaluated for impairment	432	419
Allowance for loan losses	432	419	417	330
Loans, individually evaluated for impairment	0	0
Loans, collectively evaluated for impairment	51,091	51,443
Loans	51,091	51,443
Consumer Non Real Estate Portfolio Segment [Member]
Allowance for loan losses, individually evaluated for impairment	1	1
Allowance for loan losses, collectively evaluated for impairment	679	706
Allowance for loan losses	680	707	616	644
Loans, individually evaluated for impairment	27	30
Loans, collectively evaluated for impairment	33,184	34,618
Loans	33,211	34,648
Unallocated Financing Receivables [Member]
Allowance for loan losses, individually evaluated for impairment	0	0
Allowance for loan losses, collectively evaluated for impairment	349	319
Allowance for loan losses	349	319	$ 346	$ 257
Loans, individually evaluated for impairment	0	0
Loans, collectively evaluated for impairment	0	0
Loans	$ 0	$ 0

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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The balance of financing receivables that were collectively evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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