Accrued Severance Benefits - Additional Information (Detail)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Compensation and Retirement Disclosure [Abstract]
Eligible employees for severance benefits	98.00%
Percentage of severance benefits fund	0.90%	1.02%	1.21%

Plan assets of a defined benefit plan, as a percentage of projected benefit obligation.

No definition available.

Name:	us-gaap_DefinedBenefitPlanFundedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant