Consolidated Statements Of Changes In Stockholders' Equity (USD $) In Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Beginning Balance at Aug. 31, 2010	$ 601	$ 344,144	$ (607,798)	$ 786,844	$ (21,385)	$ 502,406
Foreign currency translation adjustments					14,897	14,897
Net unrealized (loss) gain on cash flow hedges, net of tax					828	828
Net income				171,046		171,046
Dividends				(45,812)		(45,812)
Repurchase of common stock, including stock swaps			(216,584)			(216,584)
Common stock issued for employee stock plans	13	44,290				44,303
Stock-based compensation expense		25,773				25,773
Tax benefits from share-based payment arrangements		18,331				18,331
Ending Balance at Aug. 31, 2011	614	432,538	(824,382)	912,078	(5,660)	515,188
Foreign currency translation adjustments					(14,925)	(14,925)
Net unrealized (loss) gain on cash flow hedges, net of tax					(2,141)	(2,141)
Net income				188,809		188,809
Dividends				(51,887)		(51,887)
Repurchase of common stock, including stock swaps			(152,933)			(152,933)
Common stock issued for employee stock plans	9	33,383				33,392
Stock-based compensation expense		21,982				21,982
Tax benefits from share-based payment arrangements		11,159				11,159
Stock issued for acquisition of business		(11)	3,985			3,974
Purchase of common stock upon restricted stock vesting			(354)			(354)
Retirement of treasury stock	(167)	(361,482)	850,935	(489,286)
Ending Balance at Aug. 31, 2012	456	137,569	(122,749)	559,714	(22,726)	552,264
Foreign currency translation adjustments					(5,151)	(5,151)
Net unrealized (loss) gain on cash flow hedges, net of tax					(3,296)	(3,296)
Net income				198,637		198,637
Dividends				(57,832)		(57,832)
Repurchase of common stock, including stock swaps			(327,454)			(327,454)
Common stock issued for employee stock plans	25	124,124				124,149
Stock-based compensation expense		39,951				39,951
Tax benefits from share-based payment arrangements		25,225				25,225
Purchase of common stock upon restricted stock vesting			(4,714)			(4,714)
Ending Balance at Aug. 31, 2013	$ 481	$ 326,869	$ (454,917)	$ 700,519	$ (31,173)	$ 541,779