Capital Stock - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	May 31, 2013	May 31, 2012	Aug. 31, 2013	Aug. 31, 2012
Schedule of Capitalization, Equity [Line Items]
Dividends per share	$ 0.22	$ 0.20	$ 0.22	$ 0.20
Class A Common Stock $.01 Par Value | Stock Repurchase Plan
Schedule of Capitalization, Equity [Line Items]
Stock Purchase Plan, authorized purchase amount			$ 330,000,000.0
Stock Purchase Plan, purchased shares to date			7,063,962
Stock Purchase Plan, purchased amount to date			268,300,000
Stock Purchase Plan, remaining repurchase authority			$ 61,700,000