Note 7 - Earnings Per Share - Reconciliation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net earnings used in the computation of basic and diluted earnings per share (in thousands)	$ 6,122	$ 4,962	$ 12,389	$ 13,138
Weighted average shares outstanding - basic (in shares)	15,010,660	14,573,813	14,929,513	14,475,311
Common stock equivalents (in shares)	489,234	655,909	576,129	591,305
(Diluted) (in shares)	15,499,894	15,229,722	15,505,642	15,066,616
Net earnings (in dollars per share)	$ 0.41	$ 0.34	$ 0.83	$ 0.91
Net earnings (in dollars per share)	$ 0.39	$ 0.33	$ 0.80	$ 0.87