Note 3 - Loans and Allowance for Loan Losses - Recorded Investment in Loans by Risk Category (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Loans	$ 434,100	$ 414,617
Pass [Member]
Loans	426,290	405,806
Special Mention [Member]
Loans	3,106	3,623
Substandard [Member]
Loans	2,223	2,640
Doubtful [Member]
Loans	2,481	2,548
Unlikely to be Collected Financing Receivable [Member]
Loans
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member]
Loans	138,890	136,960
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member] \| Pass [Member]
Loans	135,821	133,618
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member] \| Special Mention [Member]
Loans	136	348
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member] \| Substandard [Member]
Loans	869	684
Real Estate Mortgage Portfolio Segment [Member] \| Residential Loan [Member] \| Doubtful [Member]
Loans	2,064	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	22,410	18,309
Real Estate Mortgage Portfolio Segment [Member] \| Land Loan [Member] \| Pass [Member]
Loans	22,199	18,003
Real Estate Mortgage Portfolio Segment [Member] \| Land Loan [Member] \| Special Mention [Member]
Loans	66	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	96
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	21,480	21,034
Real Estate Mortgage Portfolio Segment [Member] \| Construction Loans [Member] \| Pass [Member]
Loans	20,963	20,173
Real Estate Mortgage Portfolio Segment [Member] \| Construction Loans [Member] \| Special Mention [Member]
Loans	517	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	106,508	100,340
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member] \| Pass [Member]
Loans	103,714	97,219
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member] \| Special Mention [Member]
Loans	1,665	1,362
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member] \| Substandard [Member]
Loans	964	1,620
Real Estate Mortgage Portfolio Segment [Member] \| Commercial Real Estate Loan [Member] \| Doubtful [Member]
Loans	165	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	33,887	34,203
Commercial Portfolio Segment [Member] \| Pass [Member]
Loans	32,754	33,245
Commercial Portfolio Segment [Member] \| Special Mention [Member]
Loans	722	734
Commercial Portfolio Segment [Member] \| Substandard [Member]
Loans	290	182
Commercial Portfolio Segment [Member] \| Doubtful [Member]
Loans	121	42
Commercial Portfolio Segment [Member] \| Unlikely to be Collected Financing Receivable [Member]
Loans
Consumer Portfolio Segment [Member] \| Home Equity and Second Mortgage [Member]
Loans	53,381	50,978
Consumer Portfolio Segment [Member] \| Home Equity and Second Mortgage [Member] \| Pass [Member]
Loans	53,295	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	51	2
Consumer Portfolio Segment [Member] \| Home Equity and Second Mortgage [Member] \| Doubtful [Member]
Loans	35	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	57,544	52,793
Consumer Portfolio Segment [Member] \| All Other Consumer Excluding Home Equity and Second Mortgage [Member] \| Pass [Member]
Loans	57,544	52,629
Consumer Portfolio Segment [Member] \| All Other Consumer Excluding Home Equity and Second Mortgage [Member] \| Special Mention [Member]
Loans		161
Consumer Portfolio Segment [Member] \| All Other Consumer Excluding Home Equity and Second Mortgage [Member] \| Substandard [Member]
Loans		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

Sep. 30, 2018

Dec. 31, 2017

Loans

$ 434,100

$ 414,617

Pass [Member]

Loans

426,290

405,806

Special Mention [Member]

Loans