Leases (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Aug. 31, 2013 item
Leases [Line Items]
Lease expiration date	Sep. 30, 2030
Lease renewal option, minimum	1
Lease renewal option, maximum	4
Lease renewal options, initial term period	5 years
Minimum operating rentals receivable under noncancelable subleases	$ 14.4
Minimum capital rentals receivable under noncancelable subleases	$ 1.9
Company Drive Ins [Member]
Leases [Line Items]
Lease expiration date	Aug. 30, 2030
Refranchised Drive Ins [Member]
Leases [Line Items]
Lease renewal options, initial term period	5 years
Term of operating leases	15 years
Number of lease agreements executed	1
Lease renewal options	4
Signs [Member]
Leases [Line Items]
Lease expiration date	Mar. 31, 2021
Land And Buildings [Member]
Leases [Line Items]
Lease expiration date	Dec. 31, 2014
Capital Leases [Member]
Leases [Line Items]
Lease expiration date	Mar. 31, 2018