NOTE 5 - EARNINGS PER SHARE - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
EARNINGS PER SHARE
Net income	$ 13,739	$ 11,228	$ 13,504	$ 12,918	$ 24,967	$ 26,422
Basic EPS	$ 0.87		$ 0.86		$ 1.58	$ 1.68
Diluted EPS	$ 0.86		$ 0.85		$ 1.56	$ 1.66
Weighted average common shares outstanding (in shares)	15,747,056		15,714,588		15,771,926	15,703,967
Weighted average common shares issuable upon exercise of stock options and under the employee stock purchase plan (in shares)	148,280		223,789		185,032	226,692
Weighted average common and common equivalent shares outstanding (in shares)	15,895,336		15,938,377		15,956,958	15,930,659