Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ 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
Earnings Per Share [Abstract]
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
Weighted average common shares outstanding - basic																		48,703	52,572	55,164
Effect of dilutive employee stock options and unvested restricted stock units																		966	1,381	1,455
Weighted average common shares outstanding - diluted																		49,669	53,953	56,619
Net income per common share - basic		$ 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
Net income per common share - diluted		$ 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
Anti-dilutive securities excluded	[3]																	615	342	988

[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.

[3] Anti-dilutive securities consist of stock options and unvested RSUs that were not included in the computation of diluted earnings per share because either the exercise price of the options was greater than the average market price of the common stock or the total assumed proceeds under the treasury stock method resulted in negative incremental shares and thus the inclusion would have been anti-dilutive.