Note 5 - Loans Receivable and Related Allowance for Loan Losses - Loan Portfolio by Internal Risk Rating (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Loans	$ 598,485	$ 583,361
Residential Portfolio Segment [Member]
Loans	237,106	221,823
Home Equity Loans and Lines of Credit [Member]
Loans	99,668	99,940
Commercial Real Estate Portfolio Segment [Member]
Loans	200,169	193,068
Commercial Portfolio Segment [Member]
Loans	52,594	58,941
Consumer Portfolio Segment [Member]
Loans	8,948	9,589
Not Rated [Member]
Loans	343,315	329,119
Not Rated [Member] | Residential Portfolio Segment [Member]
Loans	235,817	220,730
Not Rated [Member] | Home Equity Loans and Lines of Credit [Member]
Loans	98,647	98,946
Not Rated [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans
Not Rated [Member] | Commercial Portfolio Segment [Member]
Loans
Not Rated [Member] | Consumer Portfolio Segment [Member]
Loans	8,851	9,443
Pass [Member]
Loans	240,654	239,420
Pass [Member] | Residential Portfolio Segment [Member]
Loans
Pass [Member] | Home Equity Loans and Lines of Credit [Member]
Loans
Pass [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans	189,273	182,460
Pass [Member] | Commercial Portfolio Segment [Member]
Loans	51,381	56,960
Pass [Member] | Consumer Portfolio Segment [Member]
Loans
Special Mention [Member]
Loans	3,935	3,221
Special Mention [Member] | Residential Portfolio Segment [Member]
Loans
Special Mention [Member] | Home Equity Loans and Lines of Credit [Member]
Loans
Special Mention [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans	3,785	2,744
Special Mention [Member] | Commercial Portfolio Segment [Member]
Loans	150	477
Special Mention [Member] | Consumer Portfolio Segment [Member]
Loans
Substandard [Member]
Loans	10,581	11,601
Substandard [Member] | Residential Portfolio Segment [Member]
Loans	1,289	1,093
Substandard [Member] | Home Equity Loans and Lines of Credit [Member]
Loans	1,021	994
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans	7,111	7,864
Substandard [Member] | Commercial Portfolio Segment [Member]
Loans	1,063	1,504
Substandard [Member] | Consumer Portfolio Segment [Member]
Loans	97	146
Doubtful [Member]
Loans
Doubtful [Member] | Residential Portfolio Segment [Member]
Loans
Doubtful [Member] | Home Equity Loans and Lines of Credit [Member]
Loans
Doubtful [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans
Doubtful [Member] | Commercial Portfolio Segment [Member]
Loans
Doubtful [Member] | Consumer Portfolio Segment [Member]
Loans