Note 18 - Earnings per Share - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings per Share
Net income	$ 98,905	$ 60,582	$ 57,408
Basic EPS	$ 6.30	$ 3.84	$ 3.65
Diluted EPS	$ 6.20	$ 3.80	$ 3.60
Weighted average common shares outstanding	15,708,744	15,771,650	15,730,016
Weighted average common shares issuable upon exercise of stock options and under the employee stock purchase plan (in shares)	235,964	180,987	237,759
Weighted average common and common equivalent shares outstanding (in shares)	15,944,708	15,952,637	15,967,775