Unusual Items - Summary of Loss Incurred on Repurchase of Debt Instruments (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	May 31, 2014	May 31, 2013	May 31, 2014	May 31, 2013
Unusual or Infrequent Item [Line Items]
Loss on 4 1/16% Debentures repurchased	$ (45.9)	$ 0	$ (50.8)	$ 0
Convertible Subordinated Debentures, Bearing Interest at 4.0625% Maturing in December 2034 [Member]
Unusual or Infrequent Item [Line Items]
Principal amount repurchased			50.2
Cash repurchase price			(100.8)
Write-off of deferred financing costs			(0.2)
Loss on 4 1/16% Debentures repurchased			$ (50.8)