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	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Effective income tax rate	41.10%	38.30%	40.90%	39.90%
Liability for unrecognized tax benefit	$ 5.0		$ 5.0		$ 4.6
Unrecognized tax benefit highly certain	$ 3.7		$ 3.7