Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Income Tax [Line Items]
Effective income tax rate	11.60%	18.70%
Income tax provision	$ (23.4)	$ (26.7)
Unrecognized tax benefits related to federal, state and foreign taxes	21.9		$ 21.5
Unrecognized tax benefits that would impact effective tax rate	18.8
Accrued interest	2.9		$ 2.6
Decrease in unrecognized tax benefits within the next 12 months	$ 4.9
Number of months unrecognized tax benefits may decrease	12 months
New Accounting Pronouncement, 2016-09
Income Tax [Line Items]
Income tax provision	$ 27.0