Note 4 - Loans and Allowance for Loan Losses - Recorded Investment of Residential and Consumer Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Loans receivable	$ 780,053	$ 777,052
Consumer Portfolio Segment [Member]
Loans receivable	141,716	143,370
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans receivable	65,195	70,226
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans receivable	23,658	22,512
Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans receivable	52,863	50,632
Residential Portfolio Segment [Member]
Loans receivable	314,761	304,079
Consumer and Residential Portfolio Segment [Member]
Loans receivable	456,477	447,449
Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans receivable	64,895	69,897
Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans receivable	23,251	22,238
Performing Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans receivable	52,475	50,318
Performing Financial Instruments [Member] | Residential Portfolio Segment [Member]
Loans receivable	308,429	297,399
Performing Financial Instruments [Member] | Consumer and Residential Portfolio Segment [Member]
Loans receivable	449,050	439,852
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans receivable	300	329
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans receivable	407	274
Nonperforming Financial Instruments [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans receivable	388	314
Nonperforming Financial Instruments [Member] | Residential Portfolio Segment [Member]
Loans receivable	6,332	6,680
Nonperforming Financial Instruments [Member] | Consumer and Residential Portfolio Segment [Member]
Loans receivable	$ 7,427	$ 7,597