Property, Equipment And Capital Leases (Narrative) (Details) (USD $)	12 Months Ended
	Aug. 31, 2013 item	Aug. 31, 2012	Aug. 31, 2011
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 681,826,000	$ 714,997,000
Accumulated depreciation related to buildings and equipment	301,236,000	295,735,000
Drive-ins under construction	0
Interest costs capitalized	700,000	300,000	0
Property And Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	35,600,000	37,200,000	37,300,000
Leased To Franchisees And Other Parties [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	157,000,000
Accumulated depreciation related to buildings and equipment	$ 51,600,000