Note 8 - Loans and Allowance for Loan Losses - Aging Analysis of Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Loans, past due	$ 3,095	$ 3,806
Loans, current	1,061,120	1,031,457
Loans, net of unearned income	1,064,215	1,035,263
Financing Receivables 30 to 89 Days Past Due [Member]
Loans, past due	1,147	2,233
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	1,948	1,573
Real Estate Portfolio Segment [Member]
Loans, net of unearned income	935,975	916,806
Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member]
Loans, past due	102	102
Loans, current	128,081	129,079
Loans, net of unearned income	128,183	129,181
Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, past due	15	15
Real Estate Portfolio Segment [Member] | Real Estate Construction and Land Development [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	87	87
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member]
Loans, past due	870	1,698
Loans, current	349,908	353,606
Loans, net of unearned income	350,778	355,304
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, past due	630	1,160
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Residential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	240	538
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member]
Loans, past due	2,117	1,914
Loans, current	454,897	430,407
Loans, net of unearned income	457,014	432,321
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, past due	496	966
Real Estate Portfolio Segment [Member] | Real Estate Mortgage Farmland and Other Commercial Enterprises [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	1,621	948
Commercial Portfolio Segment [Member]
Loans, net of unearned income	120,978	110,542
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans, past due		62
Loans, current	87,224	63,355
Loans, net of unearned income	87,224	63,417
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, past due		62
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	0	0
Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member]
Loans, past due	0	0
Loans, current	17,686	27,209
Loans, net of unearned income	17,686	27,209
Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, past due	0	0
Commercial Portfolio Segment [Member] | States and Political Subdivisions [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	0	0
Commercial Portfolio Segment [Member] | Commercial Other [Member]
Loans, past due	0	21
Loans, current	16,068	19,895
Loans, net of unearned income	16,068	19,916
Commercial Portfolio Segment [Member] | Commercial Other [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, past due	0	21
Commercial Portfolio Segment [Member] | Commercial Other [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	0	0
Consumer Portfolio Segment [Member]
Loans, net of unearned income	7,262	7,915
Consumer Portfolio Segment [Member] | Consumer Secured [Member]
Loans, past due	0	0
Loans, current	4,215	4,853
Loans, net of unearned income	4,215	4,853
Consumer Portfolio Segment [Member] | Consumer Secured [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, past due	0	0
Consumer Portfolio Segment [Member] | Consumer Secured [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	0	0
Consumer Portfolio Segment [Member] | Consumer Unsecured [Member]
Loans, past due	6	9
Loans, current	3,041	3,053
Loans, net of unearned income	3,047	3,062
Consumer Portfolio Segment [Member] | Consumer Unsecured [Member] | Financing Receivables 30 to 89 Days Past Due [Member]
Loans, past due	6	9
Consumer Portfolio Segment [Member] | Consumer Unsecured [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	$ 0	$ 0