Note 18 - Foreign Operations and Sales - Summary of Gross Sales and Long Lived Assets (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gross sales	$ 175,505	$ 112,233	$ 134,487	$ 103,711	$ 178,682	$ 99,867	$ 119,054	$ 93,935	$ 525,936	$ 491,538	$ 433,856
Long-lived assets	311,793				272,215				311,793	272,215	225,241
Domestic [Member]
Gross sales									312,895	270,773	237,146
Long-lived assets	143,540				136,692				143,540	136,692	93,142
Foreign [Member]
Gross sales									213,041	220,765	196,710
Long-lived assets	$ 168,253				$ 135,523				$ 168,253	$ 135,523	$ 132,099