Note 18 - Sales to geographic area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Europe [Member]
Total Gross sales	$ 280,593	$ 232,894	$ 210,463
North America [Member]
Total Gross sales	127,024	117,477	86,974
Asia [Member]
Total Gross sales	14,024	12,865	13,800
Other [Member]
Total Gross sales	12,215	10,914	5,975
Total Gross sales	$ 433,856	$ 374,150	$ 317,212