Financial Instruments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended		12 Months Ended							3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Terminated Interest Rate Swap Hedge	Dec. 31, 2011 Terminated Interest Rate Swap Hedge	Dec. 31, 2012 Forward Rate Contracts	Dec. 31, 2011 Forward Rate Contracts	Dec. 31, 2012 Spain Italy Portugal And Greece	Dec. 31, 2011 Spain Italy Portugal And Greece	Dec. 31, 2010 Spain Italy Portugal And Greece	Jul. 01, 2012 Spanish Government	Sep. 30, 2012 Italian Government
Derivatives, Fair Value [Line Items]
Amount in accumulated other comprehensive income, reclassified as expense to the statement of income	$ 0.4
Pre-tax loss on forward exchange contract	7.6
Interest rate swap, notional amount designated as a hedge		350
After-tax loss (gain) reclassified from AOCI into income with respect to interest rate contracts			7.0	10.0	(0.7)	(0.4)
Net revenues to customers							132.5	138.4	128.1
Amount collected from past due receivables										$ 17.5	$ 6.5