Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2013 segment	May 31, 2012
Segment Information [Abstract]
Reportable business segments			2
Company Drive-Ins	$ 108,445	$ 110,070	$ 285,607	$ 294,037
Franchise Operations	36,922	37,857	95,273	95,436
Unallocated revenues	1,267	1,500	2,903	3,317
Total revenues	146,634	149,427	383,783	392,790
Company Drive-Ins	18,389	18,670	39,673	38,764
Franchise Operations	36,922	37,857	95,273	95,436
Unallocated income	1,409	1,651	3,256	3,930
Selling, general and administrative	(16,943)	(16,951)	(48,540)	(48,452)
Depreciation and amortization	(9,783)	(10,288)	(30,447)	(31,264)
Provision for impairment of long-lived assets		(203)		(376)
Income from operations	29,994	30,736	59,215	58,038
Net interest expense	(7,017)	(7,662)	(22,323)	(23,330)
Income before income taxes	$ 22,977	$ 23,074	$ 36,892	$ 34,708