Debt - Summary Of Interest Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instruments [Abstract]
Interest incurred	$ 138.6	$ 155.7	$ 173.8
Less: interest income	1.5	2.7	4.2
Less: interest capitalized as property, plant and equipment	2.0	2.4	1.3
Interest expense, net	$ 135.1	$ 150.6	$ 168.3