Note 1 - Summary of Significant Accounting Policies (Details Textual)	12 Months Ended
	Dec. 31, 2018 USD ($)
Loan Payments Delinquency Period Beyond Which Loan is Considered Past Due	90 days
Nonaccrual Loans Performance Period	180 days
Collateral Dependent Loans, Value of Significant Properties	$ 200,000
Bank Overdrafts [Member]
Threshold Period Past Due for Write-off of Financing Receivable	45 days
Consumer Portfolio Segment [Member]
Threshold Period Past Due for Write-off of Financing Receivable	90 days
Maximum [Member]
Maturity of Time Deposits	90 days