Segment Information (Reconciliation Of Reported Revenue And Income From Operations From Segments) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Feb. 29, 2012	Feb. 28, 2011	Feb. 29, 2012 segment	Feb. 28, 2011
Segment Information [Abstract]
Reportable business segments			2
Company Drive-Ins	$ 87,185	$ 86,435	$ 183,967	$ 183,709
Franchise Operations	27,215	26,482	57,579	57,230
Unallocated revenues	684	606	1,817	1,730
Total revenues	115,084	113,523	243,363	242,669
Company Drive-Ins	9,032	8,343	20,094	20,655
Franchise Operations	27,215	26,482	57,579	57,230
Unallocated income	1,068	604	2,279	2,005
Selling, general and administrative	(16,084)	(15,285)	(31,501)	(31,566)
Depreciation and amortization	(10,510)	(10,367)	(20,976)	(20,667)
Provision for impairment of long-lived assets	(173)	(176)	(173)	(264)
Income from operations	$ 10,548	$ 9,601	$ 27,302	$ 27,393