Segment Information (Reconciliation Of Reported Revenue And Income From Operations From Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	May 31, 2012	May 31, 2011	May 31, 2012 segment	May 31, 2011
Segment Information [Abstract]
Reportable business segments			2
Company Drive-Ins	$ 110,070	$ 113,745	$ 294,037	$ 297,454
Franchise Operations	37,857	37,038	95,436	94,268
Unallocated revenues	1,500	1,315	3,317	3,045
Total revenues	149,427	152,098	392,790	394,767
Company Drive-Ins	18,670	17,734	38,764	38,389
Franchise Operations	37,857	37,038	95,436	94,268
Unallocated income	1,651	1,295	3,930	3,300
Selling, general and administrative	(16,951)	(17,212)	(48,452)	(48,778)
Depreciation and amortization	(10,288)	(10,139)	(31,264)	(30,806)
Provision for impairment of long-lived assets	(203)	(49)	(376)	(313)
Income from operations	$ 30,736	$ 28,667	$ 58,038	$ 56,060