Note 11 - Business Segments and Significant Customers (Details) - Sales by Geographic Area - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Note 11 - Business Segments and Significant Customers (Details) - Sales by Geographic Area [Line Items]
Sales by geographical area	$ 437,372	$ 499,308	$ 379,546
UNITED STATES
Note 11 - Business Segments and Significant Customers (Details) - Sales by Geographic Area [Line Items]
Sales by geographical area	17,862	22,200	22,361
CANADA
Note 11 - Business Segments and Significant Customers (Details) - Sales by Geographic Area [Line Items]
Sales by geographical area	275,771	295,027	170,632
JAPAN
Note 11 - Business Segments and Significant Customers (Details) - Sales by Geographic Area [Line Items]
Sales by geographical area	38,835	58,466	50,039
KOREA, REPUBLIC OF
Note 11 - Business Segments and Significant Customers (Details) - Sales by Geographic Area [Line Items]
Sales by geographical area	66,293	70,548	86,035
CHINA
Note 11 - Business Segments and Significant Customers (Details) - Sales by Geographic Area [Line Items]
Sales by geographical area	$ 38,611	$ 53,067	$ 50,479