Property, Plant and Equipment - Additional Information (Detail) £ in Thousands, $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	Jun. 30, 2023 USD ($)	Aug. 31, 2022 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2021 USD ($)	Mar. 31, 2024 GBP (£)
Property Plant And Equipment [Line Items]
Finance lease assets gross value			$ 3,454		$ 4,223
Finance lease, lease related accumulated amortization			1,734		$ 1,959
Depreciation expense			$ 4,582	$ 4,281
Remaining lease term					20 years
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]			Long-Term Debt and Lease Obligation, Current		Long-Term Debt and Lease Obligation, Current		Long-Term Debt and Lease Obligation, Current
Estimated cost on upgrading existing equipment						$ 26,000
Interest capitalized on strategic capital projects			$ 235	261
Depreciation on assets under finance leases			82	$ 70
Capital Expenditures [Member]
Property Plant And Equipment [Line Items]
Proceeds from disbursement agreement	$ 2,500				$ 2,500
Estimated cost on upgrading existing equipment		$ 2,500
Union Electric Steel UK Limited [Member]
Property Plant And Equipment [Line Items]
Land and buildings held as collateral			2,678				£ 2,122
UES Domestic [Member] | Construction-in-Process, Machinery and Equipment or Buildings [Member]
Property Plant And Equipment [Line Items]
Machinery and equipment purchased			$ 23,653