v3.26.3
Significant Accounting Policies - Components of Other Comprehensive Income Loss (Details) - USD ($)
$ in Millions
12 Months Ended
Aug. 31, 2026
Aug. 31, 2025
Aug. 31, 2024
Defined benefit pension plans - Net of Tax Amount      
Other comprehensive income (loss) - before tax $ 4.1 $ 47.2 $ (1.1)
Other comprehensive income (loss) - tax (expense) or benefit (0.4) (8.8) (1.2)
Other comprehensive income (loss) items, net of tax 3.7 38.4 (2.3)
Foreign Currency Items      
Foreign currency translation adjustments - Before Tax Amount      
Foreign currency translation adjustments 2.4 10.8 (5.9)
Foreign currency translation adjustments - Tax (Expense) or Benefit      
Foreign currency translation adjustments 0.0 0.0 0.0
Foreign currency translation adjustments - Net of Tax Amount      
Foreign currency translation adjustments 2.4 10.8 (5.9)
Defined benefit pension plans - Net of Tax Amount      
Other comprehensive income (loss) items, net of tax 2.4 10.8  
Actuarial amounts      
Defined benefit pension plans - Before Tax Amounts      
Actuarial gains, before tax 0.2 2.8 1.4
Defined benefit pension plans - Tax (Expense) or Benefit      
Actuarial amounts 0.0 (0.7) (0.4)
Defined benefit pension plans - Net of Tax Amount      
Actuarial gains, net of tax 0.2 2.1 1.0
Prior service cost      
Defined benefit pension plans - Before Tax Amounts      
Amortization of defined benefit pension items- Prior service cost 0.0 0.1 0.1
Defined benefit pension plans - Tax (Expense) or Benefit      
Amortization of defined benefit pension items- Prior service cost 0.0 0.0 0.0
Defined benefit pension plans - Net of Tax Amount      
Amortization of defined benefit pension items- Prior service cost 0.0 0.1 0.1
Actuarial losses      
Defined benefit pension plans - Before Tax Amounts      
Amortization of defined benefit pension items - Actuarial losses 1.5 2.6 3.3
Defined benefit pension plans - Tax (Expense) or Benefit      
Amortization of defined benefit pension items- Actuarial losses (0.4) (0.7) (0.8)
Defined benefit pension plans - Net of Tax Amount      
Amortization of defined benefit pension items- Actuarial losses 1.1 1.9 2.5
Settlement losses      
Defined benefit pension plans - Before Tax Amounts      
Amortization of defined benefit pension items- Settlement losses 0.0 30.9 0.0
Defined benefit pension plans - Tax (Expense) or Benefit      
Amortization of defined benefit pension items - Settlement losses 0.0 (7.4) 0.0
Defined benefit pension plans - Net of Tax Amount      
Amortization of defined benefit pension items- Settlement losses 0.0 23.5 0.0
Defined Benefit Pension Plans      
Defined benefit pension plans - Before Tax Amounts      
Total defined benefit plans, net - before tax 1.7 36.4 4.8
Defined benefit pension plans - Tax (Expense) or Benefit      
Total defined benefit plans, net - tax (expense) or benefit (0.4) (8.8) (1.2)
Defined benefit pension plans - Net of Tax Amount      
Total defined benefit plans, net - net of tax 1.3 27.6 $ 3.6
Other comprehensive income (loss) items, net of tax $ 1.3 $ 27.6