Note 13 - Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Unrecognized tax benefits at beginning of period	$ 3,007	$ 2,389	$ 2,555
Gross increases – tax positions in current year	651	1,188	504
Reductions due to lapse of statute of limitations	(353)	(570)	(670)
Unrecognized tax benefits at end of period	$ 3,306	$ 3,007	$ 2,389