Geographic and Segment Information - Net Sales by Region, Based on Location of Customer (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales	$ 221,872	$ 200,405	$ 601,508	$ 592,005
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales	92,914	106,698	285,250	293,509
Asia Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales	68,296	52,922	187,012	169,802
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales	8,250	17,123	21,984	48,913
North America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales	39,993	19,367	79,581	66,004
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales	11,546	3,353	25,496	11,349
Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales	$ 873	$ 942	$ 2,185	$ 2,428