Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Tax Disclosure [Abstract]
Income taxes (benefit) expense	$ (20.1)	$ 37.3	$ 27.5	$ 70.9
Effective income tax rate	46.70%	31.10%	27.40%	30.60%
Total amount of unrecognized tax benefits, including related interest and penalties	$ 57.9		$ 57.9
Unrecognized tax benefits excluding interest and penalties that if recognized would affect the effective tax rate	43.2		43.2
Total accrued interest for tax contingencies	7.4		7.4
Total accrued penalties for tax contingencies	1.5		1.5
Amount of unrecognized tax benefits that could decrease within the next 12 months	10.3		10.3
Decrease in unrecognized tax benefits due to the settlement of audits or resolution of administrative or judicial proceedings	5.4		5.4
Decrease in unrecognized tax benefits expiration of statute of limitations	$ 4.9		$ 4.9