Note 1 - Summary of Significant Accounting Policies (Details Textual)	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Loan Payments Delinquency Period Beyond Which Loan is Considered Past Due	90 days
Nonaccrual Loans Performance Period	180 days
Financing Receivable, Allowance for Credit Losses, Write-downs	$ 918,000	$ 1,679,000
Financing Receivable, Recorded Investment, Current	379,852,000	354,513,000
Impaired Financing Receivable, Unpaid Principal Balance	4,400,000	$ 6,698,000
Loans and Leases Receivable, Commitments, Fixed Rates	624,000
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
Impaired Loans Partially Charged-off [Member]
Financing Receivable, Allowance for Credit Losses, Write-downs	10,000	$ 0
Impaired Loans Partially Charged-off [Member] | Eight Loans [Member]
Financing Receivable, Allowance for Credit Losses, Write-downs	$ 345,000
Number of Loans	8
Financing Receivable, Recorded Investment, Current	$ 390,000
Impaired Financing Receivable, Unpaid Principal Balance	$ 869,000
Impaired Loans Partially Charged-off [Member] | Ten Loans [Member]
Financing Receivable, Allowance for Credit Losses, Write-downs		$ 410,000
Number of Loans		10
Financing Receivable, Recorded Investment, Current		$ 646,000
Impaired Financing Receivable, Unpaid Principal Balance		$ 1,200,000
Maximum [Member]
Maturity of Time Deposits	90 days