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, 2015		May. 31, 2015		Feb. 28, 2015		Nov. 30, 2014		Aug. 31, 2014		May. 31, 2014		Feb. 28, 2014		Nov. 30, 2013		Aug. 31, 2015	Aug. 31, 2014	Aug. 31, 2013
Selected Quarterly Financial Data [Line Items]
Total revenues	$ 175,266		$ 164,748		$ 126,219		$ 139,856		$ 163,769		$ 152,187		$ 109,741		$ 126,652		$ 606,089	$ 552,349	$ 542,585
Income from operations	40,529		36,370		16,991		22,538		36,288		31,681		12,349		18,359		116,428	98,677	89,248
Net income	$ 26,296	[1]	$ 20,442	[1]	$ 7,662	[1]	$ 10,085	[1]	$ 18,825	[1]	$ 16,776	[1]	$ 4,107	[1]	$ 8,208	[1]	$ 64,485	$ 47,916	$ 36,701
Basic income per share	$ 0.51	[2]	$ 0.39	[2]	$ 0.14	[2]	$ 0.19	[2]	$ 0.35	[2]	$ 0.31	[2]	$ 0.07	[2]	$ 0.15	[2]	$ 1.23	$ 0.87	$ 0.65
Diluted income per share	$ 0.50	[2]	$ 0.38	[2]	$ 0.14	[2]	$ 0.18	[2]	$ 0.34	[2]	$ 0.30	[2]	$ 0.07	[2]	$ 0.14	[2]	$ 1.20	$ 0.85	$ 0.64
Retroactive benefit of Work Opportunity Tax Credit and resolution of tax matters [member]
Selected Quarterly Financial Data [Line Items]
Tax expense (benefit)					$ (700)
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)
IRS's acceptance of a federal tax method change [Member}
Selected Quarterly Financial Data [Line Items]
Tax expense (benefit)															$ (500)

[1] 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 of fiscal year 2015; 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 of fiscal year 2015; 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 of fiscal year 2015. Also includes a $0.5 million tax benefit resulting from the IRS's acceptance of a federal tax method change during the first quarter of fiscal year 2014.

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