Note 4 - Loans and Allowance for Loan Losses - Risk Category of Non Consumer Loans by Class (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Loans, net of unearned income	$ 1,035,263	$ 970,975
Real Estate Portfolio Segment [Member]
Loans, net of unearned income	916,806	870,892
Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Loans, net of unearned income	129,181	120,230
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Loans, net of unearned income	355,304	350,295
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Loans, net of unearned income	432,321	400,367
Commercial Portfolio Segment [Member]
Loans, net of unearned income	110,542	90,848
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans, net of unearned income	63,417	48,607
Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member]
Loans, net of unearned income	27,209	18,933
Commercial Portfolio Segment [Member] | Commercial Other [Member]
Loans, net of unearned income	19,916	23,308
Pass [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Loans, net of unearned income	124,926	112,435
Pass [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Loans, net of unearned income	330,401	323,300
Pass [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Loans, net of unearned income	414,663	363,448
Pass [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans, net of unearned income	62,490	47,254
Pass [Member] | Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member]
Loans, net of unearned income	27,209	18,933
Pass [Member] | Commercial Portfolio Segment [Member] | Commercial Other [Member]
Loans, net of unearned income	19,898	23,308
Special Mention [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Loans, net of unearned income	396	1,413
Special Mention [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Loans, net of unearned income	9,196	12,147
Special Mention [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Loans, net of unearned income	7,556	21,088
Special Mention [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans, net of unearned income	474	764
Special Mention [Member] | Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member]
Loans, net of unearned income	0	0
Special Mention [Member] | Commercial Portfolio Segment [Member] | Commercial Other [Member]
Loans, net of unearned income	18	0
Substandard [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Loans, net of unearned income	3,859	6,382
Substandard [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Loans, net of unearned income	15,707	14,806
Substandard [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Loans, net of unearned income	10,102	15,831
Substandard [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans, net of unearned income	453	589
Substandard [Member] | Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member]
Loans, net of unearned income	0	0
Substandard [Member] | Commercial Portfolio Segment [Member] | Commercial Other [Member]
Loans, net of unearned income	0	0
Doubtful [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Loans, net of unearned income	0	0
Doubtful [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Loans, net of unearned income	0	42
Doubtful [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Loans, net of unearned income	0	0
Doubtful [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans, net of unearned income	0	0
Doubtful [Member] | Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member]
Loans, net of unearned income	0	0
Doubtful [Member] | Commercial Portfolio Segment [Member] | Commercial Other [Member]
Loans, net of unearned income	$ 0	$ 0