Note 19 - Foreign Operations and Sales - Sales to Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Gross sales	$ 178,682	$ 99,867	$ 119,054	$ 93,935	$ 156,943	$ 92,350	$ 106,379	$ 78,184	$ 491,538	$ 433,856	$ 374,150
Europe [Member]
Gross sales									321,525	280,593	232,894
North America [Member]
Gross sales									138,328	127,024	117,477
Asia [Member]
Gross sales									17,996	14,024	12,865
Other [Member]
Gross sales									$ 13,689	$ 12,215	$ 10,914