Note 9 - Earnings Per Share - Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net income	$ 6,883	$ 5,266
Weighted average shares used to compute basic EPS (in shares)	40,604	39,905
Dilutive effect of share-based awards (in shares)	48	237
Weighted average shares used to compute diluted EPS (in shares)	40,652	40,142
Basic (in dollars per share)	$ 0.17	$ 0.13
Diluted (in dollars per share)	$ 0.17	$ 0.13