Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Income Tax Expense (Benefit)	$ 24.6	$ 8.7	$ 53.8	$ 34.2
Increase Decrease In Provision For Income Taxes	$ 15.9		$ 19.6
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%		35.00%