Note 13 - Earnings Per Share - Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
EARNINGS PER SHARE
Net income (loss)	$ 1,888	$ 5,550	$ 10,613	$ 6,883	$ 3,394	$ 6,211	$ 10,203	$ 5,266	$ 24,934	$ 25,074	$ (15,417)
Weighted average shares used to compute basic EPS (in shares)									40,838,000	40,039,000	37,578,000
Dilutive effect of share-based awards (in shares)										224,000
Weighted average shares used to compute diluted EPS (in shares)									40,838,000	40,263,000	37,578,000
Basic (in dollars per share)	$ 0.05	$ 0.14	$ 0.26	$ 0.17	$ 0.08	$ 0.15	$ 0.25	$ 0.13	$ 0.61	$ 0.63	$ (0.41)
Diluted (in dollars per share)	$ 0.05	$ 0.14	$ 0.26	$ 0.17	$ 0.08	$ 0.15	$ 0.25	$ 0.13	$ 0.61	$ 0.62	$ (0.41)
Antidilutive shares									937,424		937,424