NOTE 6 - EARNINGS PER SHARE - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings per Share
Net income	$ 31,565	$ 22,349	$ 17,982	$ 17,344	$ 13,739	$ 11,228	$ 71,896	$ 42,311
Basic EPS	$ 2.02			$ 1.10			$ 4.54	$ 2.68
Diluted EPS	$ 1.99			$ 1.09			$ 4.48	$ 2.65
Weighted average common shares outstanding	15,635,123			15,767,152			15,829,124	15,770,335
Weighted average common shares issuable upon exercise of stock options and under the employee stock purchase plan (in shares)	234,675			156,426			229,296	175,497
Weighted average common and common equivalent shares outstanding (in shares)	15,869,798			15,923,578			16,058,420	15,945,832