Income Taxes (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Taxes [Line Items]
Income tax expense	$ (5.9)	$ 17.9	$ 63.9	$ 59.4
Number of years federal income tax returns are subject to examination			3 years
Period in which significant changes in unrecognized tax benefits are not expected			next twelve months
U.S. Federal [Member]
Income Taxes [Line Items]
Income tax examination, start year			2011
Income tax examination, end year			2013
State and Local [Member]
Income Taxes [Line Items]
Income tax examination, start year			2009
Income tax examination, end year			2013
Foreign [Member]
Income Taxes [Line Items]
Income tax examination, start year			2007
Income tax examination, end year			2013