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Note 8 - Loans and Related Allowance for Loan and Lease Losses (Details Textual)	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2018 USD ($)	Mar. 31, 2018	Jun. 30, 2017 USD ($)	Mar. 31, 2017	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Loans and Leases Receivable, Deferred Income, Total	$ 1,500,000				$ 1,500,000		$ 1,500,000	$ 1,500,000
Financing Receivable, Modifications, Recorded Investment	3,100,000				3,100,000		$ 3,100,000	$ 5,400,000
Number of Days Past Due								90 days
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans					654,000			$ 437,000
Provision for Loan, Lease, and Other Losses, Total	210,000		$ 170,000		420,000	$ 335,000
Real Estate Construction Porfolio Segment [Member]
Provision for Loan, Lease, and Other Losses, Total	(3,000)		10,000		(241,000)	8,000
Loans and Leases Receivable, Historical Loss Rate		(0.127%)		0.775%
Increase (Decrease) in Loans and Leases Receivable, Allowance, Percent							8.70%
Provision for Loan and Lease Losses, Total						(991,000)
Threshold For Loans Evaluated For Impairment [Member]
Loans and Leases Receivable, before Fees, Gross, Total	500,000				500,000		$ 500,000
Threshold For Loans Evaluated For Impairment [Member] | Outside Consultant [Member]
Loans and Leases Receivable, before Fees, Gross, Total	250,000				250,000		250,000
Threshold For Loans Evaluated For Impairment [Member] | Criticized Relationships [Member]
Financing Receivable, Gross	125,000				125,000		$ 125,000
Residential Loan [Member] | Real Estate Mortgage Portfolio Segment [Member]
Provision for Loan, Lease, and Other Losses, Total	$ 25,000		$ (756,000)		28,000	(991,000)
Financing Receivable, Modifications, Subsequent Default, Recorded Investment					$ 215,000	$ 33,000
Financing Receivable, Modifications, Subsequent Default, Number of Contracts					2	1

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- Definition

The amount of percentage increase (decrease) in the allowance for loans and leases receivable.

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Represents the historical loss rate for loans and leases held in portfolio, including but not limited to, commercial and consumer loans.

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The number of days past due.

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

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Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

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Amount, before allowance and fees, of loans and leases receivable. Excludes loans and leases covered under loss sharing agreements.

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Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements.

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Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period).

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Amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale.

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

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