Concentration of Risk - Additional Information (Detail)	Sep. 30, 2012 Property	Sep. 30, 2011 Restaurants
Number of properties leased	6	6

The number of units (items of property) under operating lease arrangements.

No definition available.

Name:	us-gaap_PropertySubjectToOrAvailableForOperatingLeaseNumberOfUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant