Schedule II - Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016
Allowance For Doubtful Accounts And Notes Receivable [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 1,131	$ 1,041	$ 1,105
Additions Charged to Costs and Expenses	1,825	113	(53)
Amounts Written Off Against the Allowance	(374)	(23)	(13)
(Transfer) Recoveries	2	0	2
Balance at End of Year	2,584	1,131	1,041
Accrued Liability For Drive-In Closings And Disposals [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	532	611	807
Additions Charged to Costs and Expenses	222	178	208
Amounts Written Off Against the Allowance	(241)	(243)	(376)
(Transfer) Recoveries	(18)	(14)	(28)
Balance at End of Year	$ 495	$ 532	$ 611