Convertible Senior Notes - Additional information (Detail) (USD $)	1 Months Ended	3 Months Ended	9 Months Ended
	Apr. 30, 2012	Aug. 31, 2012	Aug. 31, 2012	Aug. 31, 2011
Debt Disclosure [Line Items]
Principle amount of senior Note	$ 600,000,000	$ 600,000,000	$ 600,000,000
Convertible senior notes maturity date	May 01, 2032
Debt instrument, fixed annual interest rate	2.25%
Principal amount of note	1,000
Convertible senior notes conversion ratio	19.7750
Convertible senior notes initial conversion price	$ 50.57
Note description			(1) if the Notes are called for redemption, at any time prior to the redemption date; (2) during any fiscal quarter commencing after the fiscal quarter ending on September 2, 2012, if our last reported sale price of a share of common stock for at least 20 trading days during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding fiscal quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (3) during any five consecutive trading day period when the trading price per $1,000 principal amount of Notes is less than 98% of the product of the last reported sale price of a share of common stock and the conversion rate; and (4) upon the occurrence of certain distributions or corporate events as specified in the indenture governing the Notes.
Convertible senior notes minimum number of days out of thirty consecutive trading days that common stock price exceeded conversion price			20 days
Convertible senior notes number of consecutive trading days			30 days
Convertible senior notes minimum percentage of conversion price		130.00%	130.00%
Convertible senior notes maximum percentage of trading price		98.00%	98.00%
Observation period of convertible senior notes			35 days
Payments classification for shares repurchased			220,265,000	145,216,000
Shares repurchased			7,600,000
Debt instrument put date			May 05, 2017
Debt effective interest rate			5.50%
Debt discount, before tax	84,600,000	79,300,000	79,300,000
Debt discount, after tax		52,600,000	52,600,000
Convertible senior notes, net		520,715,000	520,715,000
Deferred issuance costs		15,600,000	15,600,000
Deferred issuance costs, liability component		13,400,000	13,400,000
Deferred issuance costs, equity component		2,200,000	2,200,000
Deferred issuance costs, equity component net of tax		1,400,000	1,400,000
Interest expense, notes		7,800,000
Convertible note contractual coupon interest		3,400,000
Amortization of debt discount		3,700,000
Amortization of debt issuance costs		700,000
Notes Issued
Debt Disclosure [Line Items]
Payments classification for shares repurchased			$ 121,000,000
Shares repurchased			3,600,000