Foreign Currency Gain (Loss), Net - Additional Information (Detail) In Millions, unless otherwise specified	Dec. 31, 2014 USD ($)	Dec. 31, 2014 KRW	Dec. 31, 2013 KRW	Dec. 31, 2012 KRW
Foreign Currency Transaction [Abstract]
Exchange rates using first base rate		1,099.2	1,055.3	1,071.1
Intercompany loan balance	$ 766