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 Disclosure [Abstract]
Effective income tax rate	30.70%	29.90%	32.90%	28.70%
U.S. federal income tax rate			35.00%	35.00%
Unrecognized tax benefits	$ 9.5		$ 9.5
Recognized tax benefits	5.1		5.1
Accrued interest and penalties related to uncertain tax positions	$ 0.8		$ 0.8