Accrued Severance Benefits - Additional Information (Detail)	Sep. 30, 2012	Sep. 30, 2011
Eligible employee for severance benefits	98.40%
Severance benefits fund	1.05%	1.20%

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