Capital Stock - Additional Information (Detail) (USD $)	9 Months Ended		1 Months Ended
	Aug. 31, 2011	Aug. 31, 2011 Class A Common Stock $.01 Par Value	Oct. 06, 2011 Class A Common Stock $.01 Par Value Stock Repurchase Plan	Oct. 31, 2011 Class A Common Stock $.01 Par Value Stock Repurchase Plan
Schedule of Capitalization, Equity [Line Items]
Stock Purchase Plan, authorized purchase amount		$ 250,000,000
Stock Purchase Plan, increase in authorized purchase amount				80,000,000
Stock Purchase Plan, purchased shares to date		5,963,581
Stock Purchase Plan, purchased amount to date		241,800,000
Stock Purchase Plan, purchased shares during period		740,968
Stock Purchase Plan, average cost per share (including commissions) during period		$ 28.33
Stock Purchase Plan, purchased amount during period	21,253,000	21,253,000
Stock Purchase Plan, remaining repurchase authority			$ 84,800,000