Note 10 - Net Income Per Share - Net Income Per Share Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net income	$ 427,374	$ 437,672	$ 242,023
Weighted-average outstanding shares - basic (in shares)	47,610	46,727	45,851
Effect of dilutive securities (in shares)	1,161	1,631	2,038
Weighted-average outstanding shares - diluted (in shares)	48,771	48,358	47,889
Earnings per share, basic (in dollars per share)	$ 8.98	$ 9.37	$ 5.28
Earnings per share, diluted (in dollars per share)	$ 8.76	$ 9.05	$ 5.05