Note 15 - Net Income Per Share - Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Net income	$ 22,710	$ 13,232
Weighted average shares outstanding - basic (in shares)	22,622	22,516
Dilutive securities (in shares)	243	220
Weighted average shares outstanding- diluted (in shares)	22,865	22,736
Net income per share, basic (in dollars per share)	$ 1.00	$ 0.59
Net income per share, diluted (in dollars per share)	$ 0.99	$ 0.58