Derivative Instruments (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2012	Aug. 31, 2011
Options Held [Member]
Derivative [Line Items]
Maximum maturity period, foreign currency derivative	one year		one year
Gains (losses) on foreign currency option contracts		$ (0.1)		$ (0.5)
Foreign currency option contracts expiration term (in years)	one		one
Forward Contracts [Member]
Derivative [Line Items]
Maximum maturity period, foreign currency derivative	90 days		90 days
Gains (losses) on foreign currency option contracts	$ (0.3)	$ (0.6)	$ 0	$ (2.6)