Note 4 - Loans and Allowance for Loan Losses (Details) - Risk Category of Loans by Class - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Credit risk profile by internally assigned rating grades:
Loans by risk rating	$ 959,275	$ 931,943
Real Estate Portfolio Segment [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	857,036	833,344
Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	115,516	97,045
Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member] | Pass [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	104,383	81,438
Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member] | Special Mention [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	1,651	2,674
Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member] | Substandard [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	9,482	12,933
Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member] | Doubtful [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	0	0
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	355,134	361,022
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member] | Pass [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	324,333	326,124
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member] | Special Mention [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	16,225	16,429
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member] | Substandard [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	14,576	18,469
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member] | Doubtful [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	0	0
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	386,386	375,277
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member] | Pass [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	343,894	327,019
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member] | Special Mention [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	22,859	27,855
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member] | Substandard [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	19,633	19,941
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member] | Doubtful [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	0	462
Commercial Portfolio Segment [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	89,820	85,186
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	48,379	47,112
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Pass [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	46,934	45,665
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Special Mention [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	937	946
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Substandard [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	508	501
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Doubtful [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	0	0
Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	17,643	22,369
Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member] | Pass [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	17,643	22,369
Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member] | Special Mention [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	0	0
Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member] | Substandard [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	0	0
Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member] | Doubtful [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	0	0
Commercial Portfolio Segment [Member] | Commercial Other [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	23,798	15,547
Commercial Portfolio Segment [Member] | Commercial Other [Member] | Pass [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	23,777	15,526
Commercial Portfolio Segment [Member] | Commercial Other [Member] | Special Mention [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	0	14
Commercial Portfolio Segment [Member] | Commercial Other [Member] | Substandard [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	21	7
Commercial Portfolio Segment [Member] | Commercial Other [Member] | Doubtful [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating	$ 0	0
Commercial Portfolio Segment [Member] | Lease Financing [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating		158
Commercial Portfolio Segment [Member] | Lease Financing [Member] | Pass [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating		158
Commercial Portfolio Segment [Member] | Lease Financing [Member] | Special Mention [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating		0
Commercial Portfolio Segment [Member] | Lease Financing [Member] | Substandard [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating		0
Commercial Portfolio Segment [Member] | Lease Financing [Member] | Doubtful [Member]
Credit risk profile by internally assigned rating grades:
Loans by risk rating		$ 0