Note 8 - Loans and Related Allowance for Loan and Lease Losses - Classes of the Loan Portfolio Summarized by Credit Quality (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Loans, total	$ 932,374	$ 923,213
Commercial And Industrial [Member]
Loans, total	99,809	101,346
Real Estate Construction Porfolio Segment [Member]
Loans, total	48,687	47,017
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Loans, total	316,856	318,157
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Loans, total	448,766	437,947
Consumer Portfolio Segment [Member]
Loans, total	18,256	18,746
Pass [Member]
Loans, total	900,140	897,759
Pass [Member] | Commercial And Industrial [Member]
Loans, total	87,415	95,621
Pass [Member] | Real Estate Construction Porfolio Segment [Member]
Loans, total	48,687	46,995
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Loans, total	310,965	312,176
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Loans, total	434,991	424,225
Pass [Member] | Consumer Portfolio Segment [Member]
Loans, total	18,082	18,742
Special Mention [Member]
Loans, total	17,876	11,829
Special Mention [Member] | Commercial And Industrial [Member]
Loans, total	8,955	1,942
Special Mention [Member] | Real Estate Construction Porfolio Segment [Member]
Loans, total
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Loans, total	715	723
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Loans, total	8,206	9,164
Substandard [Member]
Loans, total	14,358	13,625
Substandard [Member] | Commercial And Industrial [Member]
Loans, total	3,439	3,783
Substandard [Member] | Real Estate Construction Porfolio Segment [Member]
Loans, total		22
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Loans, total	5,176	5,258
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Loans, total	5,569	4,558
Substandard [Member] | Consumer Portfolio Segment [Member]
Loans, total	174	$ 4
Doubtful [Member]
Loans, total
Doubtful [Member] | Commercial And Industrial [Member]
Loans, total
Doubtful [Member] | Real Estate Construction Porfolio Segment [Member]
Loans, total
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Loans, total
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Loans, total