Note 6 - Allowance for Loan Losses and Credit Quality Information (Details Textual) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loans and Leases Receivable, Nonperforming, Nonaccrual of Interest	$ 3,144	$ 3,273	$ 4,200
Impaired Financing Receivable, Related Allowance	1,073	988
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Provision for Loan Losses	0	0	0
Loan Receivable for Which Value of Collateral Sufficient to Repay	400	700	1,400
Impaired Financing Receivable, Interest Income, Accrual Method	194	459
Financing Receivable, Modifications, Recorded Investment	3,044	3,300	2,500
Loans and Leases Receivable, Impaired, Troubled Debt, Interest Income	400	600	400
Loans and Leases Receivable, Impaired, Commitment to Lend	$ 800	400
Loan to Value Ration	75.00%
Allowance for Credit Losses, Change in Method of Calculating Impairment	$ 900	$ 600
Percentage Reserves For Loan Losses On Troubled Debt Restructurings	9.80%	6.20%
Loans and Leases Receivable, Allowance	$ 9,311	$ 9,903	9,709	$ 8,332
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Carrying Amount, Net	400
Provision for Loan and Lease Losses	(523)	(645)	(164)
Impaired Loans with Sufficient Collateral to Repay Loan [Member]
Impaired Financing Receivable, Interest Income, Accrual Method	300	600	400
Impaired Financing Receivable, Interest Income, Cash Basis Method	100	400	200
Trouble Debt Restructurings [Member]
Impaired Financing Receivable, Interest Income, Cash Basis Method	200	400	200
Acquired Loans [Member]
Provision for Loan and Lease Losses	0
Nonperforming Financial Instruments [Member]
Impaired Financing Receivable, Related Allowance	900	$ 800	$ 700
Nonperforming Financial Instruments [Member] \| Classified [Member]
Financing Receivable, Modifications, Recorded Investment	400
Performing Financial Instruments [Member] \| Classified [Member]
Financing Receivable, Modifications, Recorded Investment	$ 700

Loan receivable for which value of collateral sufficient to repay.

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- Definition

Represents the loan to value ratio.

+ References

No definition available.

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- Definition

Percentage reserves for loan losses on troubled debt restructurings.

+ References

No definition available.

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- Definition

Amount of allowance for credit losses related to receivables which had been measured under a general allowance for credit losses methodology that are now identified as troubled debt restructurings.

+ References

No definition available.

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- Definition

The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and allowance for loan losses). This relates to loans not accounted for debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References

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-Publisher FASB
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- Definition

Amount of expense related to loan loss not accounted for as debt securities, with evidence of deterioration of credit quality.

+ References

No definition available.

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- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

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- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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- Definition

Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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- Definition

Amount of allowance for credit losses related to recorded investment.

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- Definition

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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- Definition

Reflects the unfunded portion of contractual agreements to lend funds to borrowers for loans whose terms have been modified by troubled debt restructuring.

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- Definition

Reflects the carrying amount of loans deemed to be questionable as to collection on which no interest is continuing to be recognized.

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- Definition

The gross interest income that would have been recorded in the period on troubled debt restructurings, if the loans had been current in accordance with their original terms and had been outstanding throughout the period or since origination, if held for part of the period.

+ References

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- Definition

Amount of expense related to estimated loss from loan and lease transactions.

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