v3.25.4
Financial Instruments and Risk Management - Narrative (Details)
3 Months Ended 6 Months Ended
Dec. 31, 2025
USD ($)
derivative_instrument
Contract
Mar. 31, 2025
USD ($)
Sep. 30, 2025
USD ($)
Dec. 22, 2024
USD ($)
Feb. 22, 2023
Jan. 22, 2021
USD ($)
Derivative [Line Items]            
Portion or pre-tax gain included in AOCI expected to be included in earnings $ (2,800,000)          
Unrecognized pre-tax loss 21,000,000.0 $ (25,300,000)        
Interest Rate Contracts            
Derivative [Line Items]            
Fixed interest rate         1.042%  
Notional value decrease each year       $ 100,000,000.0    
Notional value 500,000,000.0         $ 500,000,000.0
Line of Credit | Senior Secured Term Loan B Facility, net of discount, due 2022            
Derivative [Line Items]            
Face amount of debt 766,200,000          
Estimate of Fair Value            
Derivative [Line Items]            
Fair market value of fixed rate long-term debt 2,459,700,000   $ 2,473,500,000      
Reported Value Measurement            
Derivative [Line Items]            
Fair market value of fixed rate long-term debt 2,538,300,000   2,537,700,000      
Designated as Hedging Instrument | Cash Flow Hedging            
Derivative [Line Items]            
Derivatives - Foreign Currency contracts 20,700,000   22,900,000      
Designated as Hedging Instrument | Cash Flow Hedging | Zinc contracts            
Derivative [Line Items]            
Notional value 30,000,000          
Derivatives - Foreign Currency contracts $ 2,600,000   1,500,000      
Derivative, number of open contracts | Contract 16          
Designated as Hedging Instrument | Cash Flow Hedging | Foreign currency contracts            
Derivative [Line Items]            
Notional value $ 97,000,000          
Derivatives - Foreign Currency contracts $ (2,900,000)   (3,900,000)      
Number of open contracts | derivative_instrument 46          
Not Designated as Hedging Instrument | Foreign currency contracts            
Derivative [Line Items]            
Derivatives - Foreign Currency contracts $ 200,000   $ (500,000)      
Not Designated as Hedging Instrument | Foreign currency contracts            
Derivative [Line Items]            
Notional value $ 134,000,000          
Number of open contracts | derivative_instrument 8