Subsequent Events - Additional Information (Detail) (Subsequent event)	1 Months Ended
Aug. 05, 2013
Subsequent event
Subsequent Event [Line Items]
Exchange offering period expiration date	Sep. 09, 2013
Document effective date	Aug. 05, 2013
Amendment date	Aug. 02, 2013

The date when a document, upon receipt and acceptance, becomes officially effective, in CCYY-MM-DD format. Usually it is a system-assigned date time value, but it may be declared by the submitter in some cases.

No definition available.

Name:	dei_DocumentEffectiveDate
Namespace Prefix:	dei_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration