Derivatives and Fair Value Measurements - Location and Amount of Gains and Losses on Derivatives Not Designated as Hedging Instruments Reported in Condensed Consolidated Statements of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Derivative Instruments Gain Loss [Line Items]
Amount of Gain/ (Loss) Recognized in Income on Derivatives			$ 15.4	$ (40.4)
Derivatives Not Designated as Hedging Instruments under ASC 815 [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of Gain/ (Loss) Recognized in Income on Derivatives	$ 4.7	$ (30.6)	3.2	(40.9)
Derivatives Not Designated as Hedging Instruments under ASC 815 [Member] | Metal Commodity Contracts [Member] | Cost of Materials Sold [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of Gain/ (Loss) Recognized in Income on Derivatives	4.0	(29.4)	1.4	(40.1)
Derivatives Not Designated as Hedging Instruments under ASC 815 [Member] | Diesel Fuel Commodity Contracts [Member] | Warehousing, Delivery, Selling, General, and Administrative [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of Gain/ (Loss) Recognized in Income on Derivatives	0.5		1.2
Derivatives Not Designated as Hedging Instruments under ASC 815 [Member] | 2028 Notes Embedded Derivative [Member] | Other Income and (Expense), Net [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of Gain/ (Loss) Recognized in Income on Derivatives		(1.3)	(0.2)	(1.0)
Derivatives Not Designated as Hedging Instruments under ASC 815 [Member] | Foreign Exchange Contracts [Member] | Other Income and (Expense), Net [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of Gain/ (Loss) Recognized in Income on Derivatives		0.1		0.2
Derivatives Not Designated as Hedging Instruments under ASC 815 [Member] | Interest Rate Swaps [Member] | Interest and Other Expense on Debt [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of Gain/ (Loss) Recognized in Income on Derivatives	0.2		0.8
Amount of Gain/(Loss) Reclassified from Accumulated Other Comprehensive Income into Income	$ (0.7)	$ (0.6)	$ (1.4)	$ (1.1)