Note 3 - Loans Receivable and Related Allowance for Loan Losses - Summary of Loans (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Total	$ 715,172,000	$ 583,361,000
Loans and Leases Receivable, Allowance, Ending Balance	6,508,000	6,127,000	$ 5,545,000
Total loans, net	708,664,000	577,234,000
Mortgage Receivable [Member]
Total	637,891,000	514,831,000
Other Loans [Member]
Total	77,281,000	68,530,000
Residential Portfolio Segment [Member]
Total	295,405,000	221,823,000
Loans and Leases Receivable, Allowance, Ending Balance	2,198,000	2,090,000	1,846,000
Residential Portfolio Segment [Member] \| Mortgage Receivable [Member]
Total	295,405,000	221,823,000
Home Equity Loans and Lines of Credit [Member]
Total	103,752,000	99,940,000
Loans and Leases Receivable, Allowance, Ending Balance	648,000	646,000	633,000
Home Equity Loans and Lines of Credit [Member] \| Mortgage Receivable [Member]
Total	103,752,000	99,940,000
Commercial Real Estate Portfolio Segment [Member]
Total	238,734,000	193,068,000
Loans and Leases Receivable, Allowance, Ending Balance	3,106,000	2,753,000	2,314,000
Commercial Real Estate Portfolio Segment [Member] \| Mortgage Receivable [Member]
Total	238,734,000	193,068,000
Commercial Portfolio Segment [Member]
Total	66,009,000	58,941,000
Loans and Leases Receivable, Allowance, Ending Balance	500,000	585,000	700,000
Commercial Portfolio Segment [Member] \| Other Loans [Member]
Total	66,009,000	58,941,000
Consumer Portfolio Segment [Member]
Total	11,272,000	9,589,000
Loans and Leases Receivable, Allowance, Ending Balance	56,000	53,000	$ 52,000
Consumer Portfolio Segment [Member] \| Other Loans [Member]
Total	$ 11,272,000	$ 9,589,000

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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