v3.26.1
Derivatives, Hedging Programs and Other Financial Instruments - Schedule of Fair Value of Derivative Financial Assets and Liabilities (Details) - USD ($)
Mar. 31, 2026
Dec. 31, 2025
Designated as Hedging Instrument | Purchase    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Liabilities $ (1,600,000) $ (100,000)
Not Designated as Hedging Instrument    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Net Amount 0 0
Fair Value, Measurements, Recurring    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets 19,300,000 9,600,000
Liabilities (7,100,000) (3,800,000)
Fair Value, Measurements, Recurring | Cash Flow Hedges | Level 1    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets 19,300,000 9,600,000
Liabilities (7,100,000) (3,800,000)
Net Amount 12,200,000 5,800,000
Fair Value, Measurements, Recurring | Cash Flow Hedges | Level 1 | Designated as Hedging Instrument | Purchase | Natural Gas    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets 700,000 700,000
Liabilities (2,300,000) (1,300,000)
Net Amount (1,600,000) (600,000)
Fair Value, Measurements, Recurring | Cash Flow Hedges | Level 1 | Designated as Hedging Instrument | Purchase | Aluminum    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets 8,700,000 2,600,000
Liabilities (100,000)  
Net Amount 8,600,000 2,600,000
Fair Value, Measurements, Recurring | Cash Flow Hedges | Level 1 | Designated as Hedging Instrument | Purchase | Fixed Price Purchase Contracts for MWTP    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets 7,000,000 3,800,000
Liabilities   (100,000)
Net Amount 7,000,000 3,700,000
Fair Value, Measurements, Recurring | Cash Flow Hedges | Level 1 | Designated as Hedging Instrument | Purchase | Fixed Price Sale Contracts for MWTP    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Liabilities (500,000) (1,600,000)
Net Amount (500,000) (1,600,000)
Fair Value, Measurements, Recurring | Cash Flow Hedges | Level 1 | Designated as Hedging Instrument | Purchase | Foreign Currency    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets   100,000
Net Amount   100,000
Fair Value, Measurements, Recurring | Cash Flow Hedges | Level 1 | Designated as Hedging Instrument | Purchase | Alloying Metals    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets 1,900,000 2,400,000
Net Amount 1,900,000 2,400,000
Fair Value, Measurements, Recurring | Cash Flow Hedges | Level 1 | Designated as Hedging Instrument | Purchase | Electricity    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Assets 1,000,000.0  
Liabilities (3,400,000)  
Net Amount (2,400,000)  
Fair Value, Measurements, Recurring | Cash Flow Hedges | Level 1 | Designated as Hedging Instrument | Sales | Fixed Price Sale Contracts for London Metal Exchange [Member]    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Liabilities (800,000) (800,000)
Net Amount $ (800,000) $ (800,000)