Income Taxes - Components of Comprehensive Provision for Income Taxes Allocation (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Schedule Of Income Tax [Line Items]
Expected tax expense, at U.S. federal statutory income tax rate of 21%	$ 6.8	$ 10.3
Incremental net tax benefit on earnings and losses of non-U.S., U.S. and non-tax group companies	(1.1)	(1.8)
Non-U.S. tax rates	0.8	0.9
Valuation allowance	1.2	(0.2)
Adjustment to the reserve for uncertain tax positions, net	(0.4)	0.6
Global intangible low-tax income, net	0.5	1.2
U.S. state income taxes and other, net	0.2	0.4
Income tax expense	8.0	11.4
Comprehensive provision for income taxes allocable to:
Net income	8.0	11.4
Other comprehensive income (loss):
Currency translation	0.2	(4.7)
Total	10.2	8.3
OPEB
Other comprehensive income (loss):
Defined benefit plans	(0.1)	(0.2)
Pension Plans
Other comprehensive income (loss):
Defined benefit plans	$ 2.1	$ 1.8