Note 10 - Fair Values (Details Textual) - USD ($)	9 Months Ended	12 Months Ended
Sep. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale, Total	$ 312,424,000	$ 334,655,000
Financing Receivable, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance, Ending Balance	$ 27,800,000	5,000,000.0
Real Estate Dependent Loans and Foreclosed Assets Estimated Selling Costs [Member]
Fair Value Inputs, Discount Factor	10.00%
Real Estate Dependent Loans and Foreclosed Assets [Member] \| Commercial Real Estate [Member] \| Minimum [Member]
Fair Value Inputs, Discount Factor	15.00%
Real Estate Dependent Loans and Foreclosed Assets [Member] \| Commercial Real Estate [Member] \| Maximum [Member]
Fair Value Inputs, Discount Factor	25.00%
Real Estate Dependent Loans and Foreclosed Assets [Member] \| Residential Real Estate [Member] \| Minimum [Member]
Fair Value Inputs, Discount Factor	25.00%
Real Estate Dependent Loans and Foreclosed Assets [Member] \| Residential Real Estate [Member] \| Maximum [Member]
Fair Value Inputs, Discount Factor	50.00%
Municipal General Obligation Bonds [Member]
Debt Securities, Available-for-sale, Total	$ 101,124,000	101,079,000
Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-sale, Total	0	0
Fair Value, Inputs, Level 3 [Member] \| Municipal General Obligation Bonds [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	1,200,000	1,700,000
Available-for-sale Securities [Member]
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount, Ending Balance	$ 0	$ 0

Discount factor used to further reduce the balance sheet carrying amount of property or other assets.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount, after valuation allowance, of financing receivable held for sale and not part of disposal group. Excludes loan covered under loss sharing agreement and loan classified as investment in debt security.

+ References

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Amount of valuation and qualifying accounts and reserves.

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