Note 12 - Fair Value Measurements - Assets Measured At Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Impaired Loans [Member]
Fair Value	$ 417	$ 6,397
Impaired Loans [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value	0	0
Impaired Loans [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value	0	0
Impaired Loans [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value	417	6,397
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Fair Value	353	3,137
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value	0	0
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value	0	0
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value	353	3,137
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Fair Value		2,909
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value		0
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value		0
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value		2,909
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Fair Value		351
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value		0
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value		0
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value		351
Impaired Loans [Member] | Commercial, Financial, and Agriculture [Member]
Fair Value	64
Impaired Loans [Member] | Commercial, Financial, and Agriculture [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value	0
Impaired Loans [Member] | Commercial, Financial, and Agriculture [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value	0
Impaired Loans [Member] | Commercial, Financial, and Agriculture [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value	64
OREO [Member]
Fair Value	1,390	6,187
OREO [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value	0	0
OREO [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value	0	0
OREO [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value	1,390	6,187
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Fair Value	27	234
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value	0	0
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value	0	0
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value	27	234
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Fair Value	1,231	4,883
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value	0	0
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value	0	0
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value	1,231	4,883
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Fair Value	132	1,070
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value	0	0
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value	0	0
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value	$ 132	$ 1,070