Commitments and Contingencies - Additional Information (Detail) $ in Millions		1 Months Ended	12 Months Ended
	Sep. 30, 2021 USD ($)	Jan. 31, 2018 USD ($)	Apr. 30, 2024 USD ($) Claim Plaintiff	Apr. 30, 2024 CAD ($) Claim Plaintiff	Apr. 30, 2023 USD ($)	Apr. 30, 2022 USD ($)	Feb. 02, 2023 USD ($)
Schedule Of Commitments And Contingencies [Line Items]
Compensatory damages sought		$ 18,600,000
Number of Product liability cases | Claim			1	1
Number of Other product liability claims | Claim			5	5
Year of other product liability claim			December 2019	December 2019
Defense and administrative costs			$ 320,000		$ 988,000	$ 729,000
Settlement fees related to product liability cases						0
Expense related to changes in product liability and municipal litigation liability			35,000		176,000	$ 1,200,000
Accrued settlement fees					1,600,000
Aggregate estimated capital expenditure			120,000,000
Environmental reserve in non-current liabilities			0		0
Construction Contract Cost							$ 114,000,000
Cost Of Machinery And Equipment Due Remainder			170,000,000
Cost Of Machinery And Equipment			160,000,000
Capital expenditures incurred			$ 157,000,000
IDB [Member]
Schedule Of Commitments And Contingencies [Line Items]
Terms of commitment			Blount County and the cities of Alcoa and Maryville, Tennessee, a public, nonprofit corporation organized and existing under the laws of the state of Tennessee, or the IDB. Pursuant to the Project Agreement, we represented to the IDB that we intend to incur, or cause to be incurred, no less than $120.0 million in aggregate capital expenditures on or before December 31, 2025, create no less than 620 new jobs, and sustain an average hourly wage of at least $25.97 at the facility. Further, pursuant to the Project Agreement, we are required to, among other things, (A) execute a facility lease and an equipment lease with the IDB; (B) cause the construction of the new facility at our sole cost and expense to commence on or before May 31, 2022; (C) incur, or cause to be incurred, aggregate capital expenditures in connection with the construction and equipping of the new facility in an aggregate amount of not less than $120.0 million on or before December 31, 2025; (D) cause the construction of the new facility to be substantially completed and for a certificate of occupancy to be issued therefore on or before December 31, 2023; (E) provide the IDB with a written report certified by one of our authorized officers, not later than January 31 of each year during the period between January 31, 2024 and January 31, 2031; and (F) make certain payments to IDB in the event that our actual capital expenditures, number of employees, or average hourly wage of such employees are less than our projections.	Blount County and the cities of Alcoa and Maryville, Tennessee, a public, nonprofit corporation organized and existing under the laws of the state of Tennessee, or the IDB. Pursuant to the Project Agreement, we represented to the IDB that we intend to incur, or cause to be incurred, no less than $120.0 million in aggregate capital expenditures on or before December 31, 2025, create no less than 620 new jobs, and sustain an average hourly wage of at least $25.97 at the facility. Further, pursuant to the Project Agreement, we are required to, among other things, (A) execute a facility lease and an equipment lease with the IDB; (B) cause the construction of the new facility at our sole cost and expense to commence on or before May 31, 2022; (C) incur, or cause to be incurred, aggregate capital expenditures in connection with the construction and equipping of the new facility in an aggregate amount of not less than $120.0 million on or before December 31, 2025; (D) cause the construction of the new facility to be substantially completed and for a certificate of occupancy to be issued therefore on or before December 31, 2023; (E) provide the IDB with a written report certified by one of our authorized officers, not later than January 31 of each year during the period between January 31, 2024 and January 31, 2031; and (F) make certain payments to IDB in the event that our actual capital expenditures, number of employees, or average hourly wage of such employees are less than our projections.
Average hourly wage	$ 25.97
Minimum
Schedule Of Commitments And Contingencies [Line Items]
Compensatory damages sought			$ 75,000
Maximum
Schedule Of Commitments And Contingencies [Line Items]
Compensatory damages sought			50,000,000
Settlement fees related to product liability cases			$ 1,600,000		$ 1,500,000
Putative Class
Schedule Of Commitments And Contingencies [Line Items]
Number of plaintiffs | Plaintiff			2	2
Putative Class | General Damages
Schedule Of Commitments And Contingencies [Line Items]
Aggregate damages claims				$ 50
Putative Class | Compensatory or Punitive Damages
Schedule Of Commitments And Contingencies [Line Items]
Aggregate damages claims				$ 100
Equipment [Member]
Schedule Of Commitments And Contingencies [Line Items]
Asset impairment charges			$ 1,900,000
Remaining net book value			$ 2,900,000