Goodwill And Other Intangibles (Narrative) (Details) (USD $)	12 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Goodwill And Other Intangibles [Line Items]
Goodwill	$ 76,997,000	$ 81,625,000	$ 82,089,000
Gross carrying amount of franchise agreements, intellectual property franchise fees and other intangibles	10,200,000	6,800,000
Accumulated amortization of intangible assets	3,400,000	2,600,000
Amortization of intangible assets	800,000	400,000	500,000
Weighted-average life of amortizable intangible assets	11 years
Estimated intangible assets amortization expense, 2013	900,000
Estimated intangible assets amortization expense, 2014	900,000
Estimated intangible assets amortization expense, 2015	900,000
Estimated intangible assets amortization expense, 2016	900,000
Estimated intangible assets amortization expense, 2017	800,000
Franchise Operations [Member]
Goodwill And Other Intangibles [Line Items]
Goodwill	6,000,000
Company Drive Ins [Member]
Goodwill And Other Intangibles [Line Items]
Goodwill	$ 71,000,000