Note 4 - Loans Receivable and Related Allowance for Loan Losses - Loan Portfolio by Internal Risk Rating (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Loans	$ 795,188	$ 809,918
Residential Portfolio Segment [Member]
Loans	298,491	308,031
Home Equity Loans and Lines of Credit [Member]
Loans	83,523	87,088
Commercial Real Estate Portfolio Segment [Member]
Loans	285,133	285,625
Commercial Portfolio Segment [Member]
Loans	84,953	89,139
Consumer Portfolio Segment [Member]
Loans	43,088	40,035
Not Rated [Member]
Loans	423,343	433,091
Not Rated [Member] | Residential Portfolio Segment [Member]
Loans	296,999	306,237
Not Rated [Member] | Home Equity Loans and Lines of Credit [Member]
Loans	83,298	86,867
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	43,046	39,987
Pass [Member]
Loans	329,020	332,416
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	250,095	249,357
Pass [Member] | Commercial Portfolio Segment [Member]
Loans	78,925	83,059
Pass [Member] | Consumer Portfolio Segment [Member]
Loans
Special Mention [Member]
Loans	16,376	21,723
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	14,801	19,669
Special Mention [Member] | Commercial Portfolio Segment [Member]
Loans	1,575	2,054
Special Mention [Member] | Consumer Portfolio Segment [Member]
Loans
Substandard [Member]
Loans	26,449	22,688
Substandard [Member] | Residential Portfolio Segment [Member]
Loans	1,492	1,794
Substandard [Member] | Home Equity Loans and Lines of Credit [Member]
Loans	225	221
Substandard [Member] | Commercial Real Estate Portfolio Segment [Member]
Loans	20,237	16,599
Substandard [Member] | Commercial Portfolio Segment [Member]
Loans	4,453	4,026
Substandard [Member] | Consumer Portfolio Segment [Member]
Loans	42	48
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