Note 5 - Loans - Performing and Nonperforming Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gross loans	$ 879,835	$ 804,211	$ 716,639
Commercial Portfolio Segment [Member]
Gross loans	149,088	153,844	132,805
Commercial Real Estate Portfolio Segment [Member]
Gross loans	578,910	496,742	427,992
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Gross loans	15,902	36,792
Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Gross loans	377,668	292,615
Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Gross loans	185,340	167,335
Residential Portfolio Segment [Member]
Gross loans	101,912	101,944	105,969
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Gross loans	41,188	45,566
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Gross loans	30,377	20,425
Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Gross loans	30,347	35,953
Consumer Portfolio Segment [Member]
Gross loans	49,925	51,681	$ 49,873
Performing Financial Instruments [Member]
Gross loans	874,036	792,825
Performing Financial Instruments [Member] | Commercial Portfolio Segment [Member]
Gross loans	147,485	151,095
Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Gross loans	15,902	36,792
Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Gross loans	377,668	291,419
Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Gross loans	184,740	166,551
Performing Financial Instruments [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Gross loans	38,279	41,990
Performing Financial Instruments [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Gross loans	29,771	18,511
Performing Financial Instruments [Member] | Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Gross loans	30,302	35,036
Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member]
Gross loans	49,889	51,431
Nonperforming Financial Instruments [Member]
Gross loans	5,799	11,386
Nonperforming Financial Instruments [Member] | Commercial Portfolio Segment [Member]
Gross loans	1,603	2,749
Nonperforming Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Gross loans
Nonperforming Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Gross loans		1,196
Nonperforming Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Gross loans	600	784
Nonperforming Financial Instruments [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Gross loans	2,909	3,576
Nonperforming Financial Instruments [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Gross loans	606	1,914
Nonperforming Financial Instruments [Member] | Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Gross loans	45	917
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member]
Gross loans	$ 36	$ 250