Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands		ASR Agreement [Member] Additional Paid-in Capital [Member]	ASR Agreement [Member] Treasury Stock [Member]	ASR Agreement [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Aug. 31, 2016					51,150,978		11,112,753
Balance at Aug. 31, 2016					$ 512	$ 623,195	$ (1,321,700)	$ 1,283,927	$ (68,553)	$ 517,381
Net income								258,259		258,259
Other comprehensive income									33,833	33,833
Common stock issued for employee stock plans (in shares)					561,960
Common stock issued for employee stock plans					$ 6	50,039				50,045
Vesting of restricted stock (in shares)					132,194		49,771
Vesting of restricted stock							$ (7,847)			(7,847)
Repurchases of common stock (in shares)			102,916	103,000			1,556,660
Repurchases of common stock							$ (253,131)			(253,131)
Stock-based compensation expense						34,183				34,183
Tax benefits from share-based payment arrangements						10,331				10,331
Accelerated share repurchase		$ 24,000	$ (24,000)	$ 0
Dividends declared								(83,363)		(83,363)
Balance (in shares) at Aug. 31, 2017					51,845,132		12,822,100
Balance at Aug. 31, 2017					$ 518	741,748	$ (1,606,678)	1,458,823	(34,720)	559,691
Net income								267,085		267,085
Other comprehensive income									(16,719)	(16,719)
Common stock issued for employee stock plans (in shares)					685,807
Common stock issued for employee stock plans					$ 8	80,983				80,991
Vesting of restricted stock (in shares)					26,599		8,070
Vesting of restricted stock							$ (1,514)			$ (1,514)
Repurchases of common stock (in shares)				(0)			1,534,782			1,534,398
Repurchases of common stock							$ (302,441)			$ (302,441)
Stock-based compensation expense						31,517				31,517
Dividends declared								(92,710)		(92,710)
Retirement of treasury shares (in shares)					(13,292,689)		(13,292,689)
Retirement of treasury shares					$ (133)	(186,717)	$ 1,697,205	(1,510,355)		0
Balance (in shares) at Aug. 31, 2018					39,264,849		1,072,263
Balance at Aug. 31, 2018					$ 393	667,531	$ (213,428)	122,843	(51,439)	525,900
Net income								352,790		352,790
Other comprehensive income									(23,821)	(23,821)
Common stock issued for employee stock plans (in shares)					753,942
Common stock issued for employee stock plans					$ 7	107,043				107,050
Vesting of restricted stock (in shares)					85,401		31,644
Vesting of restricted stock					$ 1	(1)	$ (7,241)			$ (7,241)
Repurchases of common stock (in shares)				(0)			882,445			882,445
Repurchases of common stock							$ (213,130)			$ (213,130)
Stock-based compensation expense						32,400				32,400
Dividends declared								(103,710)		(103,710)
Cumulative effect of adoption of accounting standards*	[1]							1,302	716	2,018
Balance (in shares) at Aug. 31, 2019					40,104,192		1,986,352
Balance at Aug. 31, 2019					$ 401	$ 806,973	$ (433,799)	$ 373,225	$ (74,544)	$ 672,256

[1] Includes the cumulative effect of adoption of accounting standards primarily due to both the adoption of the new revenue recognition standard (ASC 606) resulting in a cumulative increase to retained earnings related to certain fulfillment costs and the accounting standard update related to the TCJA providing for the reclassification from accumulated other comprehensive loss to retained earnings for stranded tax effects. See Notes 3 and 4 for additional information.