NOTE 6 - EARNINGS PER SHARE - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
EARNINGS PER SHARE
Net income	$ 17,344	$ 13,739	$ 11,228	$ 15,095	$ 13,504	$ 12,918	$ 42,311	$ 41,517
Basic EPS	$ 1.10			$ 0.96			$ 2.68	$ 2.64
Diluted EPS	$ 1.09			$ 0.94			$ 2.65	$ 2.60
Weighted average common shares outstanding (in shares)	15,767,152			15,739,430			15,770,335	15,715,788
Weighted average common shares issuable upon exercise of stock options and under the employee stock purchase plan (in shares)	156,426			237,312			175,497	230,232
Weighted average common and common equivalent shares outstanding (in shares)	15,923,578			15,976,742			15,945,832	15,946,020