Note 10 - 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, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
EARNINGS PER SHARE
Net income	$ 26,905	$ 33,280	$ 41,471	$ 7,035	$ 9,942	$ 4,143	$ 101,656	$ 21,120
Weighted average shares used to compute basic EPS (in shares)	44,085			44,109			44,179	43,915
Weighted average shares used to compute diluted EPS (in shares)	44,543			44,465			44,747	43,996
Basic (in dollars per share)	$ 0.61			$ 0.16			$ 2.30	$ 0.48
Diluted (in dollars per share)	$ 0.60			$ 0.16			$ 2.27	$ 0.48
Options
EARNINGS PER SHARE
Dilutive effect of stock-based awards (in shares)	458			356			560	81
Restricted Stock Units
EARNINGS PER SHARE
Dilutive effect of stock-based awards (in shares)							8
Antidilutive shares	249
Performance Stock Units
EARNINGS PER SHARE
Antidilutive shares	249