Note 12 - Segment Reporting - Income From Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income from operations	$ 21,273	$ 25,031	$ 60,294	$ 68,743
Operating Segments [Member] | United States Segment [Member]
Income from operations	28,109	30,479	82,367	88,579
Operating Segments [Member] | Europe Segment [Member]
Income from operations	4,045	5,465	12,022	12,835
Operating Segments [Member] | Corporate Unallocated and Japan Segment[Member]
Income from operations	(10,881)	(10,913)	(34,095)	(32,671)
Corporate and Reconciling Items [Member]
Income from operations	$ 21,273	$ 25,031	$ 60,294	$ 68,743