Note 11 - Earnings Per Share - Summary of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net income	$ (3,367)	$ 6,517	$ 3,024	$ 7,959
Basic (in shares)	83,231	83,921	83,222	83,708
Plus: net effect of dilutive stock options and restricted stock units (in shares)		1,905	1,615	1,826
Weighted average common shares outstanding-diluted (in shares)	83,231	85,826	84,837	85,534
Net (loss)/income per common share -- basic (in dollars per share)	$ (0.04)	$ 0.08	$ 0.04	$ 0.10
Net (loss)/income per common share -- diluted (in dollars per share)	$ (0.04)	$ 0.08	$ 0.04	$ 0.09