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				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Numerator:
Net income	$ 31,661	$ 27,533	$ 21,418	$ 18,006	$ 59,194	$ 39,424
Denominator:
Basic earnings per common share - weighted-average shares (in shares)	81,689		82,840		82,310	82,799
Effect of dilutive stock options (in shares)	326		557		307	585
Diluted earnings per common share - weighted-average shares and assumed conversions (in shares)	82,015		83,397		82,617	83,384
Basic earnings per common share (in dollars per share)	$ 0.39		$ 0.26		$ 0.72	$ 0.48
Diluted earnings per common share (in dollars per share)	$ 0.39		$ 0.26		$ 0.72	$ 0.47