Note 9 - Accumulated Other Comprehensive Loss - Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Balance	$ 585,790	$ 541,497
Balance	587,740	542,795
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Balance	(7,018)	(8,492)
Other comprehensive income (loss) before reclassifications	(2,980)	476
Amounts reclassified from accumulated other comprehensive loss	0	0
Net current-period other comprehensive income (loss)	(2,980)	476
Balance	$ (9,998)	$ (8,016)