Note 7 - Earnings Per Share - Reconciliation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net earnings used in the computation of basic and diluted earnings per share (in thousands)	$ 3,817	$ 4,341	$ 6,267	$ 8,176
Weighted average shares outstanding - basic (in shares)	14,956,221	14,501,399	14,888,940	14,426,060
Common stock equivalents (in shares)	603,183	539,032	619,577	559,003
(Diluted) (in shares)	15,559,404	15,040,431	15,508,517	14,985,063
Net earnings (in dollars per share)	$ 0.26	$ 0.30	$ 0.42	$ 0.57
Net earnings (in dollars per share)	$ 0.25	$ 0.29	$ 0.40	$ 0.55