Note 11 - Business Segments and Significant Customers - Sales by Geographic Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Sales by geographical area	$ 660,193	$ 437,372	$ 499,308
UNITED STATES
Sales by geographical area	22,499	17,862	22,200
CANADA
Sales by geographical area	437,621	275,771	295,027
JAPAN
Sales by geographical area	44,158	38,835	58,466
KOREA, REPUBLIC OF
Sales by geographical area	116,687	66,293	70,548
CHINA
Sales by geographical area	35,220	38,611	53,067
Other Geographic Areas [Member]
Sales by geographical area	$ 4,008