Derivative Instruments - Additional Information (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026 USD ($) Derivative Customer	Jun. 30, 2025 USD ($) Customer	Jun. 30, 2026 USD ($) Derivative Customer	Jun. 30, 2025 USD ($) Customer
Derivative [Line Items]
Number of subsidiaries for purchases of natural gas under existing commitments | Customer	1	2	1	2
Pre-tax termination gain				$ 559
Purchases of natural gas under existing commitments description			for one of its subsidiaries	for two of its subsidiaries
Number of subsidiaries for usage of electricity under existing commitments | Customer	1	2	1	2
Usage of electricity under existing commitments description			for another one of its subsidiaries.	for two 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	$ 209	$ 1,352	$ 4	$ 1,131
Natural Gas Usage [Member]
Derivative [Line Items]
Percentage of anticipated purchases hedged	25.00%	25.00%	25.00%	25.00%
Anticipated purchases, hedged	$ 453	$ 737	$ 453	$ 737
Time period for hedged usage description			natural gas usage through December 31, 2026	natural gas usage through December 31, 2025
Electricity Usage [Member]
Derivative [Line Items]
Percentage of anticipated purchases hedged	36.00%	28.00%	36.00%	28.00%
Anticipated purchases, hedged	$ 1,358	$ 527	$ 1,358	$ 527
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	$ 527	$ 961	$ 1,076	$ 2,085
Aluminum Purchases [Member]
Derivative [Line Items]
Percentage of anticipated purchases hedged	58.00%	75.00%	58.00%	75.00%
Time period for hedged purchases			8 months	5 months
Aluminum Purchases [Member] | Cash Flow Hedges [Member]
Derivative [Line Items]
Anticipated purchases, hedged	$ 1,101	$ 556	$ 1,101	$ 556