Note 7 - Earnings Per Share - Reconciliation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net earnings used in the computation of basic and diluted earnings per share (in thousands)	$ 2,450	$ 3,835
Weighted average shares outstanding - basic (in shares)	14,821,659	14,350,721
Common stock equivalents (in shares)	635,970	578,974
(Diluted) (in shares)	15,457,629	14,929,695
Weighted average number of shares outstanding during the period
Net earnings (in dollars per share)	$ 0.17	$ 0.27
Net earnings (in dollars per share)	$ 0.16	$ 0.26