Summary of Stock Option and Stock Appreciation Right Activity (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
	Feb. 28, 2013		Aug. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Available for Grant, Beginning Balance	4,883,919
Shares Available for Grant, Shares authorized	9,500,000
Shares Available for Grant, Options cancelled	231,878
Shares Available for Grant, Restricted stock awards granted, net of forfeitures	(3,308,885)	[1]
Shares Available for Grant, Ending Balance	11,306,912		4,883,919
Options Outstanding, beginning balance	8,677,941
Options Outstanding, options cancelled	(231,878)
Options Outstanding, options exercised	(256,382)
Options Outstanding, ending balance	8,189,681		8,677,941
Options Outstanding, exercisable ending balance	8,183,359
Aggregate Intrinsic Value, beginning balance	$ 4,719
Aggregate Intrinsic Value, ending balance	350		4,719
Aggregate Intrinsic Value, Exercisable ending balance	$ 332
Weighted-Average Exercise Price, beginning balance	$ 25.88
Weighted-Average Exercise Price, options cancelled	$ 25.13
Weighted-Average Exercise Price, options exercised	$ 13.20
Weighted-Average Exercise Price, ending balance	$ 26.29		$ 25.88
Weighted-Average Exercise Price, exercisable ending balance	$ 26.30
Weighted-Average Remaining Contractual Life	2 years 5 months 27 days		2 years 10 months 24 days
Weighted-Average Remaining Contractual Life, Exercisable ending balance	2 years 5 months 27 days

[1] Represents the maximum number of shares that can be issued based on the achievement of certain performance criteria.