Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Provisional tax expense recognized			$ 35.9
Adjustment to estimate related to executive compensation, tax benefit	$ 1.7
Tax expense for current impact of GILTI provisions	$ 1.3
Effective tax rate, percentage	17.00%	72.00%
Earnings (losses) of foreign entities	$ (1.8)	$ 8.7
Unrecognized tax benefit for uncertain tax positions	27.5		27.2
Accrued interest and penalties related to income tax liabilities	1.2		$ 1.2
Decrease in unrecognized tax benefits due to expiration of statutes of limitations and settlement of various audits	$ 0.1