Note 4 - Loans and the Allowance for Loan Losses - Credit Risk Profile by Internally Assigned Grade (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Loans	$ 573,446	$ 566,199
Consumer Portfolio Segment [Member] | Performing Financial Instruments [Member]
Loans	86,289	80,805
Consumer Portfolio Segment [Member] | Nonperforming Financial Instruments [Member]
Loans	307	410
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans	82,737	77,135
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Performing Financial Instruments [Member]
Loans	82,430	76,734
Consumer Portfolio Segment [Member] | Automobile Loan [Member] | Nonperforming Financial Instruments [Member]
Loans	307	401
Consumer Portfolio Segment [Member] | Other Loans [Member]
Loans	3,859	4,080
Consumer Portfolio Segment [Member] | Other Loans [Member] | Performing Financial Instruments [Member]
Loans	3,859	4,071
Consumer Portfolio Segment [Member] | Other Loans [Member] | Nonperforming Financial Instruments [Member]
Loans		9
Consumer Portfolio Segment [Member] | Residential Portfolio Segment [Member]
Loans	$ 86,596
Consumer Portfolio Segment [Member] | Commercial Portfolio Segment [Member]
Loans		$ 81,215