Geographic and Segment Information - Net Sales by Region, Based on Location of Customer (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales	$ 175,510	$ 170,812	$ 193,533	$ 194,322	$ 209,417	$ 220,881	$ 200,989	$ 176,049	$ 734,177	$ 807,336	$ 743,130
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales									313,634	365,682	372,736
Asia Pacific (other than Korea) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales									284,429	271,908	271,521
U.S.A. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales									100,790	124,481	75,378
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales									32,136	39,304	14,022
Others [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total segment net sales									$ 3,188	$ 5,961	$ 9,473