Note 9 - Earnings Per Share - Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
EARNINGS PER SHARE
Net income	$ 5,550	$ 10,613	$ 6,883	$ 6,211	$ 10,204	$ 5,266	$ 23,046	$ 21,681
Weighted average shares used to compute basic EPS (in shares)	40,936			40,082			40,804	40,024
Dilutive effect of share-based awards (in shares)				247				247
Weighted average shares used to compute diluted EPS (in shares)	40,936			40,329			40,804	40,271
Basic (in dollars per share)	$ 0.14			$ 0.15			$ 0.56	$ 0.54
Diluted (in dollars per share)	$ 0.14			$ 0.15			$ 0.56	$ 0.54
Antidilutive shares							937,424