Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
	Aug. 31, 2012 employee	Aug. 31, 2011	Aug. 31, 2010
Summary Of Significant Accounting Policies [Line Items]
Total restricted cash	$ 18,100,000
Restricted cash (current)	10,200,000	12,850,000
Restricted cash (noncurrent)	7,903,000	8,108,000
Number of managers per typical Company Drive-In	1
Number of hourly employees per typical Company Drive-In	25
Advertising and promotion costs	$ 22,600,000	$ 22,500,000	$ 22,500,000
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of assistant managers per typical Company Drive-In	4
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of assistant managers per typical Company Drive-In	2