Note 2 - Common Stock Outstanding and Earnings Per Share - Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020
Net income		$ 4,920	$ 5,072	$ 4,329	$ 3,847	$ 916
Weighted average shares - basic (in shares)	[1]	16,706				17,695
Effect of potentially dilutive common shares (in shares)	[2]	72				52
Weighted average number of common shares outstanding - diluted (in shares)		16,778				17,747
Earnings per share - basic (in dollars per share)		$ 0.29				$ 0.05
Earnings per share - diluted (in dollars per share)		$ 0.29				$ 0.05

[1] Excludes unvested restricted shares because they do not have dividend or voting rights.

[2] Represents the effects of the assumed exercise of stock options and vesting of non-participating restricted shares.