Note 4 - Loans - Loans by Credit Quality Indicator (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Loans	$ 835,367	$ 835,207
Commercial Loans [Member]
Loans	531,675	520,847
Accruing Loans [Member]
Loans	302,513	313,278
Nonaccrual Loans [Member]
Loans	1,179	1,082
Subtotal, Other Loans [Member]
Loans	303,692	314,360
Pass [Member] | Commercial Loans [Member]
Loans	513,574	499,208
Special Mention [Member] | Commercial Loans [Member]
Loans	4,136	8,007
Substandard [Member] | Commercial Loans [Member]
Loans	13,965	13,632
Doubtful [Member] | Commercial Loans [Member]
Loans	0	0
Unlikely to be Collected Financing Receivable [Member] | Commercial Loans [Member]
Loans	0	0
Residential Portfolio Segment [Member]
Loans	161,938	164,833
Residential Portfolio Segment [Member] | Commercial Loans [Member]
Loans	32,023	34,018
Residential Portfolio Segment [Member] | Accruing Loans [Member]
Loans	129,194	130,132
Residential Portfolio Segment [Member] | Nonaccrual Loans [Member]
Loans	721	683
Residential Portfolio Segment [Member] | Subtotal, Other Loans [Member]
Loans	129,915	130,815
Residential Portfolio Segment [Member] | Pass [Member] | Commercial Loans [Member]
Loans	31,536	33,573
Residential Portfolio Segment [Member] | Special Mention [Member] | Commercial Loans [Member]
Loans	252	291
Residential Portfolio Segment [Member] | Substandard [Member] | Commercial Loans [Member]
Loans	235	154
Residential Portfolio Segment [Member] | Doubtful [Member] | Commercial Loans [Member]
Loans	0	0
Residential Portfolio Segment [Member] | Unlikely to be Collected Financing Receivable [Member] | Commercial Loans [Member]
Loans	0	0
Commercial Real Estate Portfolio Segment [Member]
Loans	266,617	262,778
Commercial Real Estate Portfolio Segment [Member] | Commercial Loans [Member]
Loans	266,617	262,778
Commercial Real Estate Portfolio Segment [Member] | Accruing Loans [Member]
Loans	0	0
Commercial Real Estate Portfolio Segment [Member] | Nonaccrual Loans [Member]
Loans	0	0
Commercial Real Estate Portfolio Segment [Member] | Subtotal, Other Loans [Member]
Loans	0	0
Commercial Real Estate Portfolio Segment [Member] | Pass [Member] | Commercial Loans [Member]
Loans	254,254	250,674
Commercial Real Estate Portfolio Segment [Member] | Special Mention [Member] | Commercial Loans [Member]
Loans	1,661	1,858
Commercial Real Estate Portfolio Segment [Member] | Substandard [Member] | Commercial Loans [Member]
Loans	10,702	10,246
Commercial Real Estate Portfolio Segment [Member] | Doubtful [Member] | Commercial Loans [Member]
Loans	0	0
Commercial Real Estate Portfolio Segment [Member] | Unlikely to be Collected Financing Receivable [Member] | Commercial Loans [Member]
Loans	0	0
Construction, Land Acquisition and Development [Member]
Loans	22,388	20,813
Construction, Land Acquisition and Development [Member] | Commercial Loans [Member]
Loans	20,343	18,461
Construction, Land Acquisition and Development [Member] | Accruing Loans [Member]
Loans	2,027	2,352
Construction, Land Acquisition and Development [Member] | Nonaccrual Loans [Member]
Loans	18	0
Construction, Land Acquisition and Development [Member] | Subtotal, Other Loans [Member]
Loans	2,045	2,352
Construction, Land Acquisition and Development [Member] | Pass [Member] | Commercial Loans [Member]
Loans	20,343	17,704
Construction, Land Acquisition and Development [Member] | Special Mention [Member] | Commercial Loans [Member]
Loans
Construction, Land Acquisition and Development [Member] | Substandard [Member] | Commercial Loans [Member]
Loans		757
Construction, Land Acquisition and Development [Member] | Doubtful [Member] | Commercial Loans [Member]
Loans	0	0
Construction, Land Acquisition and Development [Member] | Unlikely to be Collected Financing Receivable [Member] | Commercial Loans [Member]
Loans	0	0
Commercial and Industrial [Member]
Loans	156,521	150,962
Commercial and Industrial [Member] | Commercial Loans [Member]
Loans	150,550	144,529
Commercial and Industrial [Member] | Accruing Loans [Member]
Loans	5,971	6,421
Commercial and Industrial [Member] | Nonaccrual Loans [Member]
Loans		12
Commercial and Industrial [Member] | Subtotal, Other Loans [Member]
Loans	5,971	6,433
Commercial and Industrial [Member] | Pass [Member] | Commercial Loans [Member]
Loans	147,059	137,888
Commercial and Industrial [Member] | Special Mention [Member] | Commercial Loans [Member]
Loans	463	4,193
Commercial and Industrial [Member] | Substandard [Member] | Commercial Loans [Member]
Loans	3,028	2,448
Commercial and Industrial [Member] | Doubtful [Member] | Commercial Loans [Member]
Loans	0	0
Commercial and Industrial [Member] | Unlikely to be Collected Financing Receivable [Member] | Commercial Loans [Member]
Loans	0	0
Consumer Portfolio Segment [Member]
Loans	168,119	176,784
Consumer Portfolio Segment [Member] | Commercial Loans [Member]
Loans	2,389	2,024
Consumer Portfolio Segment [Member] | Accruing Loans [Member]
Loans	165,290	174,373
Consumer Portfolio Segment [Member] | Nonaccrual Loans [Member]
Loans	440	387
Consumer Portfolio Segment [Member] | Subtotal, Other Loans [Member]
Loans	165,730	174,760
Consumer Portfolio Segment [Member] | Pass [Member] | Commercial Loans [Member]
Loans	2,389	2,024
Consumer Portfolio Segment [Member] | Special Mention [Member] | Commercial Loans [Member]
Loans
Consumer Portfolio Segment [Member] | Substandard [Member] | Commercial Loans [Member]
Loans
Consumer Portfolio Segment [Member] | Doubtful [Member] | Commercial Loans [Member]
Loans	0	0
Consumer Portfolio Segment [Member] | Unlikely to be Collected Financing Receivable [Member] | Commercial Loans [Member]
Loans	0	0
State and Political Subdivisions [Member]
Loans	59,784	59,037
State and Political Subdivisions [Member] | Commercial Loans [Member]
Loans	59,753	59,037
State and Political Subdivisions [Member] | Accruing Loans [Member]
Loans	31
State and Political Subdivisions [Member] | Nonaccrual Loans [Member]
Loans	0	0
State and Political Subdivisions [Member] | Subtotal, Other Loans [Member]
Loans	31
State and Political Subdivisions [Member] | Pass [Member] | Commercial Loans [Member]
Loans	57,993	57,345
State and Political Subdivisions [Member] | Special Mention [Member] | Commercial Loans [Member]
Loans	1,760	1,665
State and Political Subdivisions [Member] | Substandard [Member] | Commercial Loans [Member]
Loans		27
State and Political Subdivisions [Member] | Doubtful [Member] | Commercial Loans [Member]
Loans	0	0
State and Political Subdivisions [Member] | Unlikely to be Collected Financing Receivable [Member] | Commercial Loans [Member]
Loans	$ 0	$ 0