Note 15 - Fair Values of Financial Instruments (Details Textual)	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales		$ 25,000
Standby Letters of Credit	548,000	1,000,000
Real Estate Loan [Member]
Impaired Financing Receivable, Unpaid Principal Balance, Total	67,000	61,000
Home Equity Loan [Member]
Impaired Financing Receivable, Unpaid Principal Balance, Total	$ 4,000	6,000
Measurement Input, Discount Rate [Member]
Other Real Estate Owned, Measurement Input	0.1
Fair Value, Nonrecurring [Member]
Other Real Estate, Ending Balance	$ 88,000	160,000
Other Real Estate, Gross Amount	91,000	415,000
Other Real Estate, Disposals	3,000	255,000
Market and Income Approach Valuation Technique [Member]
Impaired Financing Receivable, Recorded Investment, Total	$ 0	$ 0