Note 7 - Fair Value (Details Textual)	3 Months Ended	12 Months Ended
Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	$ 141,000	$ 83,000	$ 80,000
Impaired Financing Receivable, Related Allowance	70,000	6,000	12,000
Provision for Loan and Lease Losses, Total	180,000	380,000
Fair Value, Nonrecurring [Member]
Other Real Estate, Ending Balance	6,000		160,000
Other Real Estate, Gross Amount	27,000		415,000
Other Real Estate, Disposals	21,000	0	255,000
Impaired Loans [Member]
Provision for Loan and Lease Losses, Total	63,000	$ 0
Real Estate Loan [Member]
Impaired Financing Receivable, Unpaid Principal Balance, Total	66,000		61,000
Home Equity Loan [Member]
Impaired Financing Receivable, Unpaid Principal Balance, Total	$ 5,000		6,000
Market and Income Approach Valuation Technique [Member]
Impaired Financing Receivable, Recorded Investment, Total			$ 0
Measurement Input, Discount Rate [Member]
Impaired Financing Receivable, Measurement Input	100
Other Real Estate Owned, Measurement Input	10
Collateral Pledged [Member]
Impaired Financing Receivable, with Related Allowance, Fair Value	$ 0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	63,000
Impaired Financing Receivable, Related Allowance	$ 63,000

Value of input used to measure impaired financing receivable.

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The gross amount of other real estate.

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Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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Amount of allowance for credit losses related to recorded investment.

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Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

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Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

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Carrying amount of other real estate not separately disclosed, including, but not limited to, real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. This does not include real estate assets taken in settlement of troubled loans through surrender or foreclosure.

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Disposals of other real estate not separately disclosed, including, but not limited to, real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. This excludes real estate assets taken in settlement of troubled loans through surrender or foreclosure.

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Value of input used to measure real estate owned by financial institution by financial institution which is not directly related to its business.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
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-Paragraph 2
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Amount of expense related to estimated loss from loan and lease transactions.

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