Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Income Tax [Line Items]
Effective income tax rate	18.70%	24.30%
Unrecognized tax benefits related to federal, state and foreign taxes	$ 23.3		$ 22.3
Unrecognized tax benefits that would impact effective tax rate	19.7
Accrued interest	3.1		$ 2.8
Decrease in unrecognized tax benefits within the next 12 months	$ 8.3
Number of months unrecognized tax benefits may decrease	12 months