Note 8 - EARNINGS PER SHARE - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Earnings per Share
Net income	$ 29,294	$ 15,242	$ 23,624	$ 31,565	$ 22,349	$ 17,982	$ 68,160	$ 71,896
Basic EPS	$ 1.73			$ 2.02			$ 4.25	$ 4.54
Diluted EPS	$ 1.71			$ 1.99			$ 4.20	$ 4.48
Weighted average common shares outstanding	16,900,968			15,635,123			16,030,371	15,829,124
Weighted average common shares issuable upon exercise of stock options and under the employee stock purchase plan (in shares)	209,723			234,675			213,550	229,296
Weighted average common and common equivalent shares outstanding (in shares)	17,110,691			15,869,798			16,243,921	16,058,420