Note 12 - Fair Value Measurements - Assets Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
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	239,000	3,720,000
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Fair Value	239,000	3,720,000
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		2,908,000
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Fair Value		2,908,000
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	5,000
Impaired Loans [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Fair Value	5,000
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	244,000	6,628,000
Impaired Loans [Member]
Fair Value	244,000	6,628,000
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	436,000	406,000
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Fair Value	436,000	406,000
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	3,900,000	2,252,000
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Fair Value	3,900,000	2,252,000
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	2,303,000	2,868,000
OREO [Member] | Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Fair Value	2,303,000	2,868,000
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	6,639,000	5,526,000
OREO [Member]
Fair Value	$ 6,639,000	$ 5,526,000