Note 5 - Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Provision at statutory tax rates	$ 612	$ 471	$ 1,925	$ 1,597
Provision at statutory tax rates, percentage	21.00%	21.00%	21.00%	21.00%
Tax effects of tax free interest income	$ (75)	$ (101)	$ (259)	$ (271)
Tax effects of tax free interest income, percentage	(2.57%)	(4.52%)	(2.82%)	(3.57%)
Non-deductible interest expense	$ 4	$ 4	$ 11	$ 10
Non-deductible interest expense, percentage	0.13%	0.20%	0.12%	0.14%
Bank-owned life insurance	$ (28)	$ (30)	$ (83)	$ (87)
Bank-owned life insurance, percentage	(0.96%)	(1.33%)	(0.91%)	(1.14%)
Other items, net		$ 44	$ (12)	$ 73
Other items, net, percentage	0.00%	1.99%	(0.13%)	0.96%
Income tax provision	$ 513	$ 388	$ 1,582	$ 1,322
Income tax provision, percentage	17.60%	17.34%	17.26%	17.39%

Amount of the related income tax effect of nontaxable income related to income from bank owned life insurance.

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Percentage of the related income tax effect of nontaxable income related to income from bank owned life insurance.

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Represents the portion of the difference between total income tax expense or benefit as reported in the income statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to nondeductible interest expense under enacted tax laws.

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Represents the percentage of the difference between total income tax expense or benefit as reported in the income statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to nondeductible interest expense under enacted tax laws.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments.

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Percentage of the difference, between reported income tax expense (benefit) and the expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, that is attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority interest income (expense), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, change in enacted tax rate, prior year income taxes, change in deferred tax asset valuation allowance, and other adjustments.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments.

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