Note 7 - Loans and Allowance for Loan Losses - Risk Category of Non Consumer Loans by Class (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Pass [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Loans, net of unearned income	$ 106,172,000	$ 104,383,000
Pass [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Loans, net of unearned income	314,282,000	324,333,000
Pass [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Loans, net of unearned income	356,497,000	343,894,000
Pass [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans, net of unearned income	46,298,000	46,934,000
Pass [Member] | Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member]
Loans, net of unearned income	19,922,000	17,643,000
Pass [Member] | Commercial Portfolio Segment [Member] | Commercial Other [Member]
Loans, net of unearned income	23,660,000	23,777,000
Special Mention [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Loans, net of unearned income	1,349,000	1,651,000
Special Mention [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Loans, net of unearned income	12,985,000	16,225,000
Special Mention [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Loans, net of unearned income	19,634,000	22,859,000
Special Mention [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans, net of unearned income	816,000	937,000
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	0	0
Substandard [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Loans, net of unearned income	6,933,000	9,482,000
Substandard [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Loans, net of unearned income	13,893,000	14,576,000
Substandard [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Loans, net of unearned income	17,842,000	19,633,000
Substandard [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans, net of unearned income	592,000	508,000
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	6,000	21,000
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	0
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
Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Loans, net of unearned income	114,454,000	115,516,000
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Loans, net of unearned income	341,160,000	355,134,000
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Loans, net of unearned income	393,973,000	386,386,000
Real Estate Portfolio Segment [Member]
Loans, net of unearned income	849,587,000	857,036,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans, net of unearned income	47,706,000	48,379,000
Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member]
Loans, net of unearned income	19,922,000	17,643,000
Commercial Portfolio Segment [Member] | Commercial Other [Member]
Loans, net of unearned income	23,666,000	23,798,000
Commercial Portfolio Segment [Member]
Loans, net of unearned income	91,294,000	89,820,000
Loans, net of unearned income	$ 950,716,000	$ 959,275,000