Derivatives and Fair Value Measurements - Assets and Liabilities Measured and Recorded at Fair Value (Detail) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Asset Derivatives, Fair Value	$ 20.4	$ 13.2
Liability Derivatives, Fair Value	26.9	36.5
Fair Value, Measurements, Recurring [Member] | Derivatives Not Designated as Hedging Instruments under ASC 815 [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Asset Derivatives, Fair Value	20.4	13.0
Liability Derivatives, Fair Value	26.9	36.5
Fair Value, Measurements, Recurring [Member] | Derivatives Not Designated as Hedging Instruments under ASC 815 [Member] | Level 2 [Member] | Metal Commodity Contracts [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Asset Derivatives, Fair Value	19.3	13.0
Liability Derivatives, Fair Value	26.9	35.1
Fair Value, Measurements, Recurring [Member] | Derivatives Not Designated as Hedging Instruments under ASC 815 [Member] | Level 2 [Member] | Diesel Fuel Commodity Contracts [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Asset Derivatives, Fair Value	0.8
Fair Value, Measurements, Recurring [Member] | Derivatives Not Designated as Hedging Instruments under ASC 815 [Member] | Level 2 [Member] | Interest Rate Swaps [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Asset Derivatives, Fair Value	$ 0.3
Liability Derivatives, Fair Value		1.4
Fair Value, Measurements, Recurring [Member] | Derivatives Not Designated as Hedging Instruments under ASC 815 [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Asset Derivatives, Fair Value		0.2
Fair Value, Measurements, Recurring [Member] | Derivatives Not Designated as Hedging Instruments under ASC 815 [Member] | Level 3 [Member] | 2028 Notes Embedded Derivative [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Asset Derivatives, Fair Value		$ 0.2