Note 4 - Loans - Performing and Nonperforming Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Gross loans	$ 900,420	$ 879,835
Commercial Portfolio Segment [Member]
Gross loans	137,870	142,405
Commercial Real Estate Portfolio Segment [Member]
Gross loans	613,201	585,593
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Gross loans	14,723	15,902
Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Gross loans	405,192	377,668
Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Gross loans	193,286	192,023
Residential Portfolio Segment [Member]
Gross loans	101,192	101,912
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Gross loans	40,425	41,188
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Gross loans	30,247	30,377
Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Gross loans	30,520	30,347
Consumer Portfolio Segment [Member]
Gross loans	48,157	49,925
Performing Financial Instruments [Member]
Gross loans	896,204	874,036
Performing Financial Instruments [Member] | Commercial Portfolio Segment [Member]
Gross loans	136,761	140,802
Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Gross loans	14,723	15,902
Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Gross loans	405,192	377,668
Performing Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Gross loans	193,286	191,423
Performing Financial Instruments [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Gross loans	37,586	38,279
Performing Financial Instruments [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Gross loans	30,059	29,771
Performing Financial Instruments [Member] | Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Gross loans	30,475	30,302
Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member]
Gross loans	48,122	49,889
Nonperforming Financial Instruments [Member]
Gross loans	4,216	5,799
Nonperforming Financial Instruments [Member] | Commercial Portfolio Segment [Member]
Gross loans	1,109	1,603
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
Nonperforming Financial Instruments [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Gross loans		600
Nonperforming Financial Instruments [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Gross loans	2,839	2,909
Nonperforming Financial Instruments [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Gross loans	188	606
Nonperforming Financial Instruments [Member] | Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Gross loans	45	45
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member]
Gross loans	$ 35	$ 36