Note 11. Business Segments and Significant Customers (Detail) - Sales Information By Geographic Area (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Sales by geographic area	$ 470,495	$ 421,846	$ 312,548
United States [Member]
Sales by geographic area	24,409	24,708	19,127
Canada [Member]
Sales by geographic area	240,569	124,862	136,248
Mexico [Member]
Sales by geographic area		16,258	20,413
Japan [Member]
Sales by geographic area	60,963	62,740	43,356
Korea [Member]
Sales by geographic area	92,919	94,114	77,492
China [Member]
Sales by geographic area	51,635	73,257	15,912
Belgium [Member]
Sales by geographic area		$ 25,907