Note 5 - Earnings Per Share - Computation of Basic and Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net earnings, basic	$ 720	$ 764	$ 1,436	$ 1,631
Weighted-average Shares, basic (in shares)	3,116,307	3,144,068	3,150,082	3,142,244
Net earnings, per share amount, basic (in dollars per share)	$ 0.23	$ 0.24	$ 0.45	$ 0.52
Effect of dilutive securities-incremental shares from assumed conversion of options (in shares)	63	6,068	158	4,634
Net earnings, diluted	$ 720	$ 764	$ 1,436	$ 1,631
Weighted-average Shares, diluted (in shares)	3,116,370	3,150,136	3,150,240	3,146,878
Net earnings, per share amount, diluted (in dollars per share)	$ 0.23	$ 0.24	$ 0.45	$ 0.52