Note 5 - Loans (Details Textual) $ in Thousands			12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Unamortized Loan Commitment and Origination Fees and Unamortized Discounts or Premiums	$ 2,900	$ 2,300	$ 2,900	$ 2,300
Age of Appraisals That Will Considered as Stale			1 year
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans			$ 353	228	$ 649
Impaired Financing Receivable, Recorded Investment	18,794	21,390	$ 18,794	21,390
Percentage of Collateral Coverage to Loan Balance to Consider Restructured Loan to Performing and Accrual Status			100.00%
Financing Receivable, Modifications, Recorded Investment	$ 12,100	$ 15,900	$ 12,100	$ 15,900
Financing Receivable, Modifications, Number of Contracts	121	112	8	13	7
Troubled Debt Restructurings Percentage of Gross Portfolio Loans	1.50%	2.22%	1.50%	2.22%
Doubtful Grade Remaining Outstanding Period, Minimum				180 days
Loans and Leases Receivable, Allowance	$ 11,544	$ 11,180	$ 11,544	$ 11,180
Percentage of Allowance for Loan and Lease Losses out of Net Loans	1.44%	1.56%	1.44%	1.56%
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Asset	$ 229,400	$ 230,600	$ 229,400	$ 230,600
Reserve for Unfunded Commitments Included in Other Liabilities	$ 695	695	$ 695	$ 695
Percentage of Loan Portfolio Secured by Real Estate	75.00%		75.00%
Percentage of Unallocated Allowance Amount out of Allowance for Loan and Lease Losses			4.00%	5.00%
Maximum Loan to Value, Percentage			80.00%
Loans and Leases Receivable, Impaired, Commitment to Lend	$ 0	0	$ 0	$ 0
Performing Financial Instruments [Member]
Impaired Financing Receivable, Recorded Investment	$ 7,100	$ 6,900	$ 7,100	$ 6,900
Maximum [Member]
Frequency of External Appraisals Updating			1 year
Loans 30 Days Past Due [Member]
Number of Days for Loan Past Due			30 days
Loans 60 Days Past Due [Member]
Number of Days for Loan Past Due			60 days
Loans 90 Days Past Due [Member]
Number of Days for Loan Past Due			90 days