Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Tax Contingency [Line Items]
Effective tax rate	33.10%	32.20%	31.50%	30.50%
Overall increase (decrease) in unrecognized tax benefits (UTPs)			$ (5.8)	$ (34.5)
Gross [Member]
Income Tax Contingency [Line Items]
Overall increase (decrease) in unrecognized tax benefits (UTPs)	(13.7)		(8.9)
Net [Member]
Income Tax Contingency [Line Items]
Overall increase (decrease) in unrecognized tax benefits (UTPs)	$ (12.1)		$ (4.3)