Derivative Instruments (Narrative) (Details) - Forward Contracts [Member] - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
May 31, 2016
May 31, 2015
May 31, 2016
May 31, 2015
Derivative [Line Items]        
Minimum maturity period, foreign currency derivative     30 days  
Maximum maturity period, foreign currency derivative     1 year  
Gains (losses) on foreign currency forward contracts $ 2.3 $ (1.2) $ 0.8 $ (2.5)