Goodwill And Other Intangibles (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 75,756	$ 76,734	$ 77,076
Gross carrying amount of franchise agreements, intellectual property franchise fees and other intangibles	9,300	9,200
Accumulated amortization of intangible assets	6,600	5,700
Amortization of intangible assets	$ 1,000	$ 900	$ 900
Weighted-average life of amortizable intangible assets	11 years 6 months 6 days
Estimated intangible assets amortization expense, 2018	$ 300
Estimated intangible assets amortization expense, 2019	300
Estimated intangible assets amortization expense, 2020	300
Estimated intangible assets amortization expense, 2021	300
Estimated intangible assets amortization expense, 2022	$ 300