Note 3 - Loans and Allowance for Loan Losses - Recorded Investment in Loans by Risk Category (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Loans	$ 424,649	$ 414,617
Pass [Member]
Loans	415,791	405,806
Special Mention [Member]
Loans	3,637	3,623
Substandard [Member]
Loans	2,889	2,640
Doubtful [Member]
Loans	2,332	2,548
Unlikely to be Collected Financing Receivable [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member]
Loans	136,176	136,960
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member] \| Pass [Member]
Loans	133,138	133,618
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member] \| Special Mention [Member]
Loans	379	348
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member] \| Substandard [Member]
Loans	798	684
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member] \| Doubtful [Member]
Loans	1,861	2,310
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member] \| Unlikely to be Collected Financing Receivable [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] \| Land Loan [Member]
Loans	21,443	18,309
Real Estate Mortgage Portfolio Segment [Member] \| Land Loan [Member] \| Pass [Member]
Loans	21,061	18,003
Real Estate Mortgage Portfolio Segment [Member] \| Land Loan [Member] \| Special Mention [Member]
Loans		157
Real Estate Mortgage Portfolio Segment [Member] \| Land Loan [Member] \| Substandard [Member]
Loans	49	149
Real Estate Mortgage Portfolio Segment [Member] \| Land Loan [Member] \| Doubtful [Member]
Loans	333
Real Estate Mortgage Portfolio Segment [Member] \| Land Loan [Member] \| Unlikely to be Collected Financing Receivable [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] \| Construction Loans [Member]
Loans	21,917	21,034
Real Estate Mortgage Portfolio Segment [Member] \| Construction Loans [Member] \| Pass [Member]
Loans	21,644	20,173
Real Estate Mortgage Portfolio Segment [Member] \| Construction Loans [Member] \| Special Mention [Member]
Loans	273	861
Real Estate Mortgage Portfolio Segment [Member] \| Construction Loans [Member] \| Substandard [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] \| Construction Loans [Member] \| Doubtful [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] \| Construction Loans [Member] \| Unlikely to be Collected Financing Receivable [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member]
Loans	104,976	100,340
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member] \| Pass [Member]
Loans	101,232	97,219
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member] \| Special Mention [Member]
Loans	1,944	1,362
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member] \| Substandard [Member]
Loans	1,800	1,620
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member] \| Doubtful [Member]
Loans		139
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member] \| Unlikely to be Collected Financing Receivable [Member]
Loans
Commercial Portfolio Segment [Member]
Loans	33,861	34,203
Commercial Portfolio Segment [Member] \| Pass [Member]
Loans	32,647	33,245
Commercial Portfolio Segment [Member] \| Special Mention [Member]
Loans	899	734
Commercial Portfolio Segment [Member] \| Substandard [Member]
Loans	239	182
Commercial Portfolio Segment [Member] \| Doubtful [Member]
Loans	76	42
Commercial Portfolio Segment [Member] \| Unlikely to be Collected Financing Receivable [Member]
Loans
Consumer Portfolio Segment [Member] \| Home Equity and Second Mortgage [Member]
Loans	52,494	50,978
Consumer Portfolio Segment [Member] \| Home Equity and Second Mortgage [Member] \| Pass [Member]
Loans	52,431	50,919
Consumer Portfolio Segment [Member] \| Home Equity and Second Mortgage [Member] \| Special Mention [Member]
Loans
Consumer Portfolio Segment [Member] \| Home Equity and Second Mortgage [Member] \| Substandard [Member]
Loans	1	2
Consumer Portfolio Segment [Member] \| Home Equity and Second Mortgage [Member] \| Doubtful [Member]
Loans	62	57
Consumer Portfolio Segment [Member] \| Home Equity and Second Mortgage [Member] \| Unlikely to be Collected Financing Receivable [Member]
Loans
Consumer Portfolio Segment [Member] \| All Other Consumer Excluding Home Equity and Second Mortgage [Member]
Loans	53,782	52,793
Consumer Portfolio Segment [Member] \| All Other Consumer Excluding Home Equity and Second Mortgage [Member] \| Pass [Member]
Loans	53,638	52,629
Consumer Portfolio Segment [Member] \| All Other Consumer Excluding Home Equity and Second Mortgage [Member] \| Special Mention [Member]
Loans	142	161
Consumer Portfolio Segment [Member] \| All Other Consumer Excluding Home Equity and Second Mortgage [Member] \| Substandard [Member]
Loans	2	3
Consumer Portfolio Segment [Member] \| All Other Consumer Excluding Home Equity and Second Mortgage [Member] \| Doubtful [Member]
Loans
Consumer Portfolio Segment [Member] \| All Other Consumer Excluding Home Equity and Second Mortgage [Member] \| Unlikely to be Collected Financing Receivable [Member]
Loans

Note 3 - Loans and Allowance for Loan Losses - Recorded Investment in Loans by Risk Category (Details) - USD ($)
$ in Thousands

Jun. 30, 2018

Dec. 31, 2017

Loans

$ 424,649

$ 414,617

Pass [Member]

Loans

415,791

405,806

Special Mention [Member]

Loans