Note 2 - Earnings per Common Share - Basic and Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Numerator:
Net income	$ 25,646	$ 31,661	$ 27,533	$ 21,274	$ 21,418	$ 18,006	$ 84,840	$ 60,698
Denominator:
Basic earnings per common share - weighted-average shares (in shares)	81,061			82,907			81,889	82,835
Effect of dilutive stock options (in shares)	286			465			266	545
Diluted earnings per common share - weighted-average shares and assumed conversions (in shares)	81,347			83,372			82,155	83,380
Basic earnings per common share (in dollars per share)	$ 0.32			$ 0.26			$ 1.04	$ 0.73
Diluted earnings per common share (in dollars per share)	$ 0.32			$ 0.26			$ 1.03	$ 0.73