Note 7 - Earnings per Share - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Earnings per Share
Net income	$ 25,797	$ 26,726
Basic EPS	$ 1.53	$ 1.59
Diluted EPS	$ 1.52	$ 1.58
Weighted average common shares outstanding	16,900,785	16,783,348
Weighted average common shares issuable upon exercise of stock options and under the employee stock purchase plan (in shares)	113,207	127,327
Weighted average common and common equivalent shares outstanding	17,013,992	16,910,675