Property, Equipment And Capital Leases (Schedule Of Property, Equipment And Capital Leases) (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2017	Aug. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 570,686	$ 722,530
Accumulated depreciation	(272,233)	(345,284)
Property and equipment, net	298,453	377,246
Capital leases	45,315	43,991
Accumulated amortization	(31,388)	(28,857)
Capital leases, net	13,927	15,134
Property, equipment and capital leases, net	312,380	392,380
Land [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	117,402	154,420
Buildings And Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	251,695	325,068
Drive-In Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	75,410	132,488
Brand Technology Development And Other Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, at cost	$ 126,179	$ 110,554
Minimum [Member] | Buildings And Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	8 years
Minimum [Member] | Drive-In Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Minimum [Member] | Brand Technology Development And Other Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	2 years
Maximum [Member] | Buildings And Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	25 years
Maximum [Member] | Drive-In Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Maximum [Member] | Brand Technology Development And Other Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years