CONVERTIBLE SENIOR NOTES (Details) (USD $)			1 Months Ended	3 Months Ended	9 Months Ended
	Aug. 31, 2014	Nov. 30, 2013	Apr. 30, 2012 Convertible Debt	Aug. 31, 2014 Convertible Debt	Aug. 31, 2014 Convertible Debt	Aug. 31, 2013 Convertible Debt	Apr. 23, 2012 Convertible Debt	Aug. 31, 2014 Significant other Observable Inputs (Level 2)
Debt Instrument [Line Items]
Principal amount of senior note			$ 600,000,000.0	$ 600,000,000	$ 600,000,000
Debt instrument, fixed annual interest rate			2.25%				2.25%
Principal amount of note			1,000	1,000	1,000
Convertible senior notes conversion ratio (shares)			19.7750
Convertible senior notes initial conversion price (in dollars per share)			$ 50.57
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%
Consecutive trading day period					5 days
Convertible senior notes maximum percentage of trading price				98.00%	98.00%
Stock observation period					35 days
Debt effective interest rate						5.50%
Debt discount, before tax			84,600,000	47,700,000	47,700,000
Debt discount, after tax			52,600,000
Convertible senior notes, net	552,266,000	540,022,000		552,300,000	552,300,000
Deferred issuance costs			15,600,000
Deferred issuance costs, liability component			13,400,000
Deferred issuance costs, equity component			2,200,000
Deferred issuance costs, equity component net of tax			1,400,000
Interest expense				8,200,000
Loan origination fees and issuance costs				3,400,000	3,400,000
Amortization of debt discount				4,100,000
Amortization of debt issuance costs				700,000
Convertible senior notes, fair value disclosures								$ 605,400,000