Selected Quarterly Financial Data (Schedule Of Selected Quarterly Financial Data) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Aug. 31, 2016		May 31, 2016		Feb. 29, 2016		Nov. 30, 2015		Aug. 31, 2015		May 31, 2015		Feb. 28, 2015		Nov. 30, 2014		Aug. 31, 2016	Aug. 31, 2015	Aug. 31, 2014
Selected Quarterly Financial Data [Line Items]
Total revenues	$ 162,118		$ 165,239		$ 133,160		$ 145,803		$ 175,266		$ 164,748		$ 126,219		$ 139,856		$ 606,320	$ 606,089	$ 552,349
Income from operations	40,315		38,880		22,212		26,045		40,529		36,370		16,991		22,538		127,452	116,428	98,677
Net income	$ 25,437	[1]	$ 15,353	[1]	$ 10,819	[1]	$ 12,458	[1]	$ 26,296	[1]	$ 20,442	[1]	$ 7,662	[1]	$ 10,085	[1]	$ 64,067	$ 64,485	$ 47,916
Basic income per share	$ 0.54	[2]	$ 0.32	[2]	$ 0.22	[2]	$ 0.25	[2]	$ 0.51	[2]	$ 0.39	[2]	$ 0.14	[2]	$ 0.19	[2]	$ 1.32	$ 1.23	$ 0.87
Diluted income per share	$ 0.53	[2]	$ 0.31	[2]	$ 0.22	[2]	$ 0.24	[2]	$ 0.50	[2]	$ 0.38	[2]	$ 0.14	[2]	$ 0.18	[2]	$ 1.29	$ 1.20	$ 0.85
After tax gain on sale of real estate [Member]
Selected Quarterly Financial Data [Line Items]
Quarterly charges and credits that affect comparability					$ (1,200)
Retroactive benefit of Work Opportunity Tax Credit and resolution of tax matters [member]
Selected Quarterly Financial Data [Line Items]
Tax expense (benefit)					$ (600)								$ (700)
After tax loss from early extinguishment of debt [Member]
Selected Quarterly Financial Data [Line Items]
Quarterly charges and credits that affect comparability			$ 5,700
After tax gain on sale of Company Drive-Ins [Member]
Selected Quarterly Financial Data [Line Items]
Quarterly charges and credits that affect comparability	$ (700)
FIN 48 release of income tax credits and deductions [Member]
Selected Quarterly Financial Data [Line Items]
Tax expense (benefit)	$ (3,000)
Federal tax benefit of prior-year statutory tax deduction [Member]
Selected Quarterly Financial Data [Line Items]
Tax expense (benefit)									$ (1,500)		$ (1,700)
Retroactive effect of federal tax law change [Member]
Selected Quarterly Financial Data [Line Items]
Tax expense (benefit)											$ 600
Change in deferred tax valuation allowance [Member]
Selected Quarterly Financial Data [Line Items]
Tax expense (benefit)									$ (1,700)

[1] For fiscal year 2016, includes the after tax gain on the sale of real estate of $1.2 million and a tax benefit of $0.6 million from the retroactive reinstatement of the Work Opportunity Tax Credit and resolution of income tax matters in the second quarter, the $5.7 million after tax loss from early extinguishment of debt in the third quarter and the after tax gain on the sale of Company Drive-Ins of $0.7 million and the FIN 48 release of income tax credits and deductions of $3.0 million in the fourth quarter. For fiscal year 2015, includes a tax benefit of $0.7 million from the retroactive reinstatement of the Work Opportunity Tax Credit and resolution of income tax matters in the second quarter, a federal tax benefit of $1.7 million from the recognition of a prior-year statutory tax deduction and a tax expense of $0.6 million from the retroactive effect of federal tax law change during the third quarter and a federal tax benefit of $1.5 million from the recognition of a prior-year statutory tax deduction and $1.7 million from a change in deferred tax valuation allowance during the fourth quarter.

[2] The sum of per share data may not agree to annual amounts due to rounding.