Note 15 - Fair Values of Financial Instruments (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	$ 25,000
Other Real Estate, Ending Balance		0
Standby Letters of Credit	1,000,000	156,000
Real Estate Loan [Member]
Impaired Financing Receivable, Unpaid Principal Balance, Total	61,000	68,000
Home Equity Loan [Member]
Impaired Financing Receivable, Unpaid Principal Balance, Total	6,000	8,000
Fair Value, Measurements, Nonrecurring [Member]
Other Real Estate, Ending Balance	160,000	0
Other Real Estate, Gross Amount	415,000
Other Real Estate, Disposals	255,000
Market and Income Approach Valuation Technique [Member]
Impaired Financing Receivable, Recorded Investment, Total	0	0
Corporate Debt Securities [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3		$ 8,000,000
Fair Value, Inputs, Level 3 [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	25,000
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Other Real Estate, Ending Balance	$ 160,000