Derivative Instruments - Additional Information (Detail) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2026 USD ($) Derivative Customer	Sep. 30, 2025 USD ($)	Sep. 30, 2026 USD ($) Derivative Customer	Sep. 30, 2025 USD ($)
Derivative [Line Items]
Number of subsidiaries for purchases of natural gas under existing commitments \| Customer	1		1
Pre-tax termination gain			$ 559
Purchases of natural gas under existing commitments description			for one of its subsidiaries	for one of its subsidiaries
Number of subsidiaries for usage of electricity under existing commitments \| Customer	1		1
Usage of electricity under existing commitments description			for another one of its subsidiaries.	for another one of its subsidiaries
Number of derivative instruments holds for trading purposes \| Derivative	0		0
Life of underlying asset			15 years
Gains on foreign exchange transactions included in other income net	$ 819	$ 57	$ 823	$ 1,188
Natural Gas Usage [Member]
Derivative [Line Items]
Percentage of anticipated purchases hedged	24.00%	26.00%	24.00%	26.00%
Anticipated purchases, hedged	$ 1,072	$ 286	$ 1,072	$ 286
Time period for hedged usage description			natural gas usage through December 31, 2027	natural gas usage through December 31, 2025
Electricity Usage [Member]
Derivative [Line Items]
Percentage of anticipated purchases hedged	36.00%	31.00%	36.00%	31.00%
Anticipated purchases, hedged	$ 1,135	$ 198	$ 1,135	$ 198
Time period for hedged usage description			electricity usage through December 31, 2027	electricity usage through December 31, 2025
Natural Gas And Electricity Purchased [Member]
Derivative [Line Items]
Purchase of natural gas or electricity	$ 423	$ 756	$ 1,499	$ 2,841
Aluminum Purchases [Member]
Derivative [Line Items]
Percentage of anticipated purchases hedged	67.00%	75.00%	67.00%	75.00%
Time period for hedged purchases			7 months	6 months
Aluminum Purchases [Member] \| Cash Flow Hedges [Member]
Derivative [Line Items]
Anticipated purchases, hedged	$ 1,146	$ 571	$ 1,146	$ 571

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Number of subsidiaries for usage of electricity under existing commitments.

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Percentage of anticipated requirements which are covered by cash flow hedges.

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Pre-tax termination gain.

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Usage of electricity under existing commitments description.

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The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

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Nominal or face amount used to calculate payment on derivative.

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Amount, before tax, of realized and unrealized gain (loss) from foreign currency transaction.

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