NOTE 6 - EARNINGS PER SHARE - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings per Share
Net income	$ 22,349	$ 17,982	$ 13,739	$ 11,228	$ 40,331	$ 24,967
Basic EPS	$ 1.41		$ 0.87		$ 2.55	$ 1.58
Diluted EPS	$ 1.39		$ 0.86		$ 2.52	$ 1.56
Weighted average common shares outstanding	15,813,932		15,747,056		15,808,788	15,771,926
Weighted average common shares issuable upon exercise of stock options and under the employee stock purchase plan (in shares)	231,307		148,280		226,606	185,032
Weighted average common and common equivalent shares outstanding (in shares)	16,045,239		15,895,336		16,035,394	15,956,958