Note 4 - Loans and Allowance for Loan Losses - Recorded Investment of Residential and Consumer Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Loans receivable	$ 775,086	$ 772,774
Consumer Portfolio Segment [Member]
Loans receivable	137,089	140,362
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans receivable	61,729	63,770
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans receivable	21,894	22,882
Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans receivable	53,466	53,710
Residential Portfolio Segment [Member]
Loans receivable	307,879	310,253
Consumer and Residential Portfolio Segment [Member]
Loans receivable	444,968	450,615
Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans receivable	61,536	63,470
Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans receivable	21,535	22,490
Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans receivable	53,162	53,224
Performing Financial Instruments [Member] | Residential Portfolio Segment [Member]
Loans receivable	301,652	303,879
Performing Financial Instruments [Member] | Consumer and Residential Portfolio Segment [Member]
Loans receivable	437,885	443,063
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans receivable	193	300
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans receivable	359	392
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans receivable	304	486
Nonperforming Financial Instruments [Member] | Residential Portfolio Segment [Member]
Loans receivable	6,227	6,374
Nonperforming Financial Instruments [Member] | Consumer and Residential Portfolio Segment [Member]
Loans receivable	$ 7,083	$ 7,552