Description of Business, The Separation, Agreements with the Former Parent and Separation Costs, and Basis of Presentation - Additional Information (Detail) $ in Millions	12 Months Ended
	May 31, 2025 USD ($) Facility Segment Jointventure	May 31, 2024 USD ($)	May 31, 2023 USD ($)	Dec. 01, 2023 USD ($)
Significant Accounting Policies [Line Items]
Number of years of service	70 years
Cash distribution made as part of spinoff				$ 150.0
Cash and cash equivalents received as contribution of assets and liabilities				$ 3.8
Separation costs	$ 0.0	$ 19.5	$ 17.5
Number of operating joint ventures | Jointventure	4
Number of operating segments | Segment	1
Number of reportable segments | Segment	1
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration]	srt:ChiefExecutiveOfficerMember
Number of facilities operated | Facility	15
Allowance for doubtful accounts increase (decrease)	$ 0.6
Receivables, allowances	3.8	3.2
Depreciation Expenses	59.4	58.5	62.7
Advertising Expenses	$ 1.0	$ 0.8	$ 1.2
Workforce Subject to Collective Bargaining Arrangements | Labor Force Concentration Risk
Significant Accounting Policies [Line Items]
Concentration risk percentage	24.00%
Joint Venture Transactions
Significant Accounting Policies [Line Items]
Number of operating joint ventures | Jointventure	3
Number of facilities operated | Facility	16
Serviacero Worthington
Significant Accounting Policies [Line Items]
Percent of ownership own a noncontrolling interest held in unconsolidated joint venture	50.00%
Spartan | Joint Venture Transactions
Significant Accounting Policies [Line Items]
Percent of controlling interest by the Company	52.00%
TWB | Joint Venture Transactions
Significant Accounting Policies [Line Items]
Percent of controlling interest by the Company	55.00%
WSCP | Joint Venture Transactions
Significant Accounting Policies [Line Items]
Percent of controlling interest by the Company	63.00%
WSP | Joint Venture Transactions
Significant Accounting Policies [Line Items]
Percent of controlling interest by the Company	51.00%
Minimum
Significant Accounting Policies [Line Items]
Period allowed for payment of dues to customers	30 days
Maximum
Significant Accounting Policies [Line Items]
Period allowed for payment of dues to customers	60 days
Building and Building Improvements | Minimum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	10 years
Building and Building Improvements | Maximum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	40 years
Machinery and Equipment | Minimum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	3 years
Machinery and Equipment | Maximum
Significant Accounting Policies [Line Items]
Property, plant and equipment, estimated useful life	20 years