Income Taxes - Components of Comprehensive Provision for Income Taxes Allocation (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Schedule Of Income Tax [Line Items]
Expected tax expense, at U.S. federal statutory income tax rate of 21%	$ 10.3	$ 8.9
Incremental net tax benefit on earnings and losses of non-U.S., U.S. and non-tax group companies	(1.8)	(0.2)
Non-U.S. tax rates	0.9	2.3
Valuation allowance	(0.2)	1.0
Adjustment to the reserve for uncertain tax positions, net	0.6	0.5
Global intangible low-tax income, net	1.2	0.7
U.S. state income taxes and other, net	0.4	1.0
Income tax expense	11.4	14.2
Comprehensive provision for income taxes allocable to:
Net income	11.4	14.2
Other comprehensive income (loss):
Currency translation	(4.7)
Total	8.3	15.7
OPEB
Other comprehensive income (loss):
Defined benefit plans	(0.2)
Pension Plans
Other comprehensive income (loss):
Defined benefit plans	$ 1.8	$ 1.5