Property, Equipment And Capital Leases (Narrative) (Details) (USD $)	12 Months Ended
	Aug. 31, 2014	Aug. 31, 2013	Aug. 31, 2012
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 720,776,000	$ 681,826,000
Accumulated depreciation related to buildings and equipment	298,580,000	301,236,000
Interest costs capitalized	500,000	700,000	300,000
Property And Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	37,600,000	35,600,000	37,200,000
Leased To Franchisees And Other Parties [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	163,800,000
Accumulated depreciation related to buildings and equipment	$ 58,200,000
Drive-ins under construction
Property, Plant and Equipment [Line Items]
Drive-ins under construction	2