Pensions and Other Postretirement Benefits - Narrative (Details) $ in Millions	12 Months Ended
	Apr. 30, 2025 USD ($) plan	Apr. 30, 2024 USD ($)	Apr. 30, 2023 USD ($)	Dec. 31, 2023
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
Eligibility condition for covered employees to avail the benefits of unfunded, defined postretirement plans that provide health care and life insurance benefits	when they reach age 55 and have attained 10 years of credited service
Settlement loss (gain)	$ 0.0	$ 3.2	$ 7.4
Expected benefit payments for the defined benefit pension and other postretirement in Year One	150.5
Expected benefit payments for the defined benefit pension and other postretirement in Year Two	22.8
Expected benefit payments for the defined benefit pension and other postretirement in Year Three	22.6
Expected benefit payments for the defined benefit pension and other postretirement in Year Four	21.8
Expected benefit payments for the defined benefit pension and other postretirement in Year Five	21.7
Expected benefit payments for the defined benefit pension and other postretirement in Years Six through Ten	$ 108.5
Number of multiemployer pension plans | plan	1
Multiemployer Plan, Pension, Significant, Employer Contribution, Cost	$ 2.8	$ 2.9
Multiemployer plan actual funded status				45.20%
USPensionPlanActualRateOfReturnOnAssets	8.50%	(2.90%)
Following Fiscal Year
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
Multiemployer Plan, Pension, Significant, Future Employer Contribution, Amount	$ 2.8
Fixed income
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
Approximate percentage of assets to be invested in company's current investment policy	75.00%
Equity Securities
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
Approximate percentage of assets to be invested in company's current investment policy	15.00%
Cash and Cash Equivalents [Member]
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
Approximate percentage of assets to be invested in company's current investment policy	10.00%
Other Postretirement Benefits Plan
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate	2034
Settlement loss (gain)	$ 0.0	$ 0.0	0.0
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	0.0	0.0	0.0
Net periodic benefit cost (credit)	0.7	1.3	1.5
Defined Benefit Plan, Benefit Obligation	$ 50.6	$ 48.9	$ 54.7
Other Postretirement Benefits Plan | United States [Member]
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
Assumed health care trend rate for next fiscal year	7.00%
Assumed health care trend rate for participants under age 65	5.00%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	5.86%	5.15%	4.52%
Discount rate used to determine service cost	5.92%	5.23%	4.64%
Discount rate used to determine interest cost	5.77%	5.06%	4.11%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	0.00%	0.00%	0.00%
Other Postretirement Benefits Plan | CANADA
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
Assumed health care trend rate for next fiscal year	4.50%
Assumed health care trend rate for participants under age 65	4.50%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	5.12%	4.62%	4.50%
Discount rate used to determine service cost	5.21%	4.73%	4.69%
Discount rate used to determine interest cost	5.07%	4.65%	4.18%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	0.00%	0.00%	0.00%
Defined Benefit Pension Plans
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
Settlement loss (gain)	$ 0.0	$ 3.2	$ 7.4
Expected amount to be contributed by the Company to the defined benefit pension plans in Year One	1.0
Expected direct benefit payments to be made by the Company in Year One	9.0
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	12.3	16.1	15.4
Net periodic benefit cost (credit)	10.5	8.9	15.7
Defined Benefit Plan, Benefit Obligation	$ 332.6	$ 345.9	$ 379.7
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Used to Determine Interest Cost, Next Year	4.91%
Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate, Next Year	5.21%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Used to Determine Service Cost, Next Year	6.07%
Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Asset, Next Years	5.48%
Defined Benefit Plan, Net Periodic Benefit Cost Increase Due to 50 Basis-Point Decrease In Expected Return	$ 1.2
Defined Benefit Plan, Net Periodic Benefit Cost Increase Due to 50 Basis-Point Decrease In Discount Rate	0.2
Defined Benefit Plan, Benefit Obligation Increase Due to 50 Basis-Point Decrease In Discount Rate	$ 13.1
Defined Benefit Pension Plans | United States [Member]
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	5.43%	5.19%	4.59%
Discount rate used to determine service cost	6.06%	5.38%	4.77%
Discount rate used to determine interest cost	5.38%	5.08%	4.26%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	4.70%	5.35%	4.51%
Expected amount to be recognized during the next fiscal year of amortization of net actuarial losses in net periodic benefit cost	$ 43.6
Defined Benefit Pension Plans | CANADA
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
Defined Benefit Plan, Gain (Loss) Due to Settlement, 2021 Canada Buy-Out Contract	$ 0.0	$ 3.2
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	5.07%	4.59%	2.41%
Discount rate used to determine service cost	0.00%	0.00%	0.00%
Discount rate used to determine interest cost	5.04%	4.65%	2.33%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets	0.00%	3.30%	1.60%
Minimum
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
High Quality Corporate Bonds with Duration Range	10 years
Maximum
Pensions and Other Postretirement Benefits (Additional Textual) [Abstract]
High Quality Corporate Bonds with Duration Range	13 years