Note 11 - Stockholders' Equity and Earnings Per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net income	$ 298,304	$ 228,860	$ 279,135
Basic EPS, income	$ 298,304	$ 228,860	$ 279,135
Basic EPS, income (in shares)	78,268,369	79,584,560	79,999,703
Basic EPS, income (in dollars per share)	$ 3.81	$ 2.88	$ 3.49
Effect of dilutive stock options and RSU (in shares)	302,269	193,287	248,190
Diluted EPS, income	$ 298,304	$ 228,860	$ 279,135
Diluted EPS, income (in shares)	78,570,638	79,777,847	80,247,893
Diluted EPS, income (in dollars per share)	$ 3.80	$ 2.87	$ 3.48