Derivatives - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended		3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Jun. 30, 2013 Fair Value Hedging	Jun. 30, 2012 Fair Value Hedging	Jun. 30, 2013 Fair Value Hedging	Jun. 30, 2012 Fair Value Hedging	Mar. 31, 2012 Senior Notes Eight Point Twenty Five Percent Due March Fifteen Two Thousand Nineteen	Mar. 31, 2012 Senior Notes Four Point Nine Five Percent Due April One Two Thousand Fourteen	Apr. 09, 2010 Senior Notes Four Point Nine Five Percent Due April One Two Thousand Fourteen
Derivative [Line Items]
Aggregate notional value of foreign exchange forward contracts	$ 504.6		$ 504.6		$ 654.2
Derivative, inception date										Mar. 13, 2012	Apr. 09, 2010
Notional amount of interest rate fair value hedge derivatives										400.0		600.0
Debt instrument, face amount										450.0
Interest rate										8.25%	4.95%	4.95%
Maturity date										Mar. 15, 2019	Apr. 01, 2014
Repayment of Debt											341.8
Terminated portion of interest rate swap agreement, notional amount											342.0
Proceeds from termination of interest rate swaps				11.0
Reduction to interest expense	$ (65.5)	$ (63.6)	$ (128.3)	$ (124.3)		$ 2.2	$ 2.0	$ 4.5	$ 4.0