Long-term Debt - Summary of Loss Incurred on Repurchase of Debt Instruments (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Aug. 31, 2014	Aug. 31, 2013	Aug. 31, 2014	Aug. 31, 2013
Debt Instrument [Line Items]
Loss on 4 1/16% Debentures repurchased	$ (9.8)	$ 0	$ (60.6)	$ 0
4.0625% Convertible Subordinated Debentures [Member]
Debt Instrument [Line Items]
Principal amount repurchased			59.6
Cash repurchase price			(119.9)
Write-off of deferred financing costs			(0.3)
Loss on 4 1/16% Debentures repurchased			$ (60.6)