Note 4 - Loans Receivable and Related Allowance for Loan Losses - Summary of Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Loans, gross	$ 706,991	$ 715,172
Loans and Leases Receivable, Allowance, Ending Balance	6,639	6,508	$ 5,935	$ 6,127
Total loans, net	700,352	708,664
Mortgage Receivable [Member]
Loans, gross	628,771	637,891
Other Loans [Member]
Loans, gross	78,220	77,281
Residential Portfolio Segment [Member]
Loans, gross	293,903	295,405
Loans and Leases Receivable, Allowance, Ending Balance	2,256	2,198	1,919	2,090
Residential Portfolio Segment [Member] \| Mortgage Receivable [Member]
Loans, gross	293,903	295,405
Home Equity Loans and Lines of Credit [Member]
Loans, gross	102,553	103,752
Loans and Leases Receivable, Allowance, Ending Balance	650	648	651	646
Home Equity Loans and Lines of Credit [Member] \| Mortgage Receivable [Member]
Loans, gross	102,553	103,752
Commercial Real Estate Portfolio Segment [Member]
Loans, gross	232,315	238,734
Loans and Leases Receivable, Allowance, Ending Balance	3,043	3,106	2,751	2,753
Commercial Real Estate Portfolio Segment [Member] \| Mortgage Receivable [Member]
Loans, gross	232,315	238,734
Commercial Portfolio Segment [Member]
Loans, gross	67,317	66,009
Loans and Leases Receivable, Allowance, Ending Balance	635	500	560	585
Commercial Portfolio Segment [Member] \| Other Loans [Member]
Loans, gross	67,317	66,009
Consumer Portfolio Segment [Member]
Loans, gross	10,903	11,272
Loans and Leases Receivable, Allowance, Ending Balance	55	56	$ 54	$ 53
Consumer Portfolio Segment [Member] \| Other Loans [Member]
Loans, gross	$ 10,903	$ 11,272

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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