Property, Equipment And Capital Leases (Narrative) (Details) (USD $)	12 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 714,997,000	$ 712,113,000
Accumulated depreciation related to buildings and equipment	295,735,000	273,209,000
Drive-ins under construction	0
Property And Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	37,200,000	37,300,000	38,600,000
Leased To Franchisees And Other Parties [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	219,800,000
Accumulated depreciation related to buildings and equipment	$ 69,700,000