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Financial instruments and derivatives - Additional Information (Details)
MMBTU in Millions, BTU in Millions
 12 Months Ended
Dec. 31, 2023
USD ($)
BTU
MMBTU
t
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Jan. 21, 2022
Dec. 29, 2021
USD ($)
bank
Derivative [Line Items]          
Derivatives net of tax $ 63,391,000 $ (70,198,000) $ 396,833,000    
Derivative instrument, number of counter-parties | bank         2
Gain (loss) on settlement   5,201,000      
Anticipated usage percentage covered by a swap contract for the current fiscal year (percent) $ (6,790,000) (8,692,000)      
Unsecured Debt          
Derivative [Line Items]          
Debt         $ 150,000,000,000
2.85% notes due February 2032          
Derivative [Line Items]          
Stated interest rate (percent) 2.85%        
Debt $ 495,785,000 495,264,000      
2.85% notes due February 2032 | Unsecured Debt          
Derivative [Line Items]          
Stated interest rate (percent)       2.85%  
Debt Instrument, Face Amount         $ 500,000,000
Cash Flow Hedges | Hedge derivatives, net:          
Derivative [Line Items]          
Price risk cash flow hedge derivative, at fair value, net (41,000) (172,000)      
Commodity gain (loss) expected to be reclassified to the income statement during the next 12 months (41,000)        
Fair value of foreign currency cash flow hedges 1,502,000 (299,000)      
Foreign currency gain (loss) expected to be reclassified to the income statement during the next 12 months $ 1,502,000        
Natural gas swaps | Non-hedge derivatives, net:          
Derivative [Line Items]          
Approximate amount of commodity covered by swap contracts outstanding (btu) | MMBTU 5.4        
Anticipated usage percentage covered by a swap contract for the next fiscal year (percent) 0.75        
Natural gas swaps | Cash Flow Hedges | Hedge derivatives, net:          
Derivative [Line Items]          
Approximate amount of commodity covered by swap contracts outstanding (btu) | BTU 0.1        
Anticipated usage percentage covered by a swap contract for the next fiscal year (percent) 0.01        
Aluminum Swaps | Cash Flow Hedges | Hedge derivatives, net:          
Derivative [Line Items]          
Anticipated usage percentage covered by a swap contract for the next fiscal year (percent) 0.10        
Approximate amount of commodity covered by swap contracts outstanding (tonne) | t 488        
Forward Contracts | Cash Flow Hedges | Hedge derivatives, net:          
Derivative [Line Items]          
Fair value of foreign currency cash flow hedges $ 0 $ (564,000)      
Foreign currency gain (loss) expected to be reclassified to the income statement during the next 12 months 0        
Foreign currency gain (loss) reclassified to the income statement (401,000)        
Currency Swap | Net investment hedge          
Derivative [Line Items]          
Net purchase/(sell) position of derivatives 500,000,000        
Gain (loss) on derivative used in net investment hedge, after tax (5,073,000)        
Derivatives net of tax (3,779,000)        
Net investment hedges, tax $ 1,294,000