Income Taxes (Details) - USD ($)	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 47,000,000.0	$ 77,900,000
Components of earnings before income taxes and the consolidated income tax provision:
Domestic	13,200,000	(3,400,000)	$ 50,700,000
Foreign	(15,600,000)	(136,000,000.0)	166,200,000
Income (Loss) from Subsidiaries, before Tax	(2,400,000)	(139,400,000)	216,900,000
Current provision:
Federal	(16,200,000)	49,400,000	24,000,000.0
State	4,000,000.0	(2,200,000)	2,900,000
Foreign	88,800,000	57,200,000	81,500,000
Total current provision	76,600,000	104,400,000	108,400,000
Deferred (benefit) provision:
Federal	(73,000,000.0)	(22,800,000)	3,800,000
State	(3,700,000)	(100,000)	1,600,000
Foreign	(54,400,000)	(16,700,000)	(11,000,000.0)
Total deferred (benefit) provision	(131,100,000)	(39,600,000)	(5,600,000)
Income tax expense	$ (54,500,000)	$ 64,800,000	$ 102,800,000
Reconciliation of the effective income tax rate with the U.S. federal statutory income tax rate
Federal statutory rates (as a percent)	21.00%	21.00%	21.00%
Adjustments resulting from the tax effect of:
State income taxes, net of federal benefit	(4.20%)	(0.80%)	1.40%
Foreign income tax rate differential (as a percent)	(1133.30%)	(4.30%)	6.40%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Payment Arrangement, Percent	(75.00%)	(1.20%)	1.30%
Effective Income Tax Rate Reconciliation, Deduction, Percent	(387.50%)	(11.30%)	3.60%
Valuation allowance (as a percent)	454.20%	(4.20%)	3.30%
Effective Income Tax Rate Reconciliation, Tax Contingency, Percent	804.20%	(24.80%)	(1.40%)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Percent	(595.80%)	(30.20%)	0.00%
effective income tax rate, deferred tax impact of rate change	2287.50%	0.00%	0.00%
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Percent	612.50%	7.10%	3.90%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	187.50%	0.00%	(2.90%)
Effective Income Tax Rate Reconciliation, Transaction Costs, Percent	0.00%	(0.50%)	7.20%
Effective Income Tax Rate Reconciliation, Tax Settlement,	0.00%	0.00%	2.00%
Other, net (as a percent)	99.70%	2.70%	1.60%
Effective income tax rate (as a percent)	2270.80%	(46.50%)	47.40%
Deferred tax assets:
Employee benefit accruals	$ 16,000,000.0	$ 21,200,000
Loss and tax credit carryforwards	27,200,000	35,600,000
Interest Limitation Carryforwards	47,800,000	48,700,000
Operating lease liabilities	22,600,000	40,700,000
Warranty reserves	4,800,000	6,400,000
Deferred Tax Asset, In-Process Research and Development	18,700,000	20,100,000
Self-insurance reserves	2,500,000	2,500,000
Capital loss	56,900,000	0
Allowance for doubtful accounts	4,000,000.0	3,300,000
Inventory, net	5,100,000	12,400,000
Other, net	7,700,000	10,500,000
Total deferred tax assets before valuation allowance	213,300,000	201,400,000
Less valuation allowance	(9,000,000.0)	(21,200,000)
Total deferred tax assets, net	204,300,000	180,200,000
Deferred tax liabilities:
Depreciation	(19,800,000)	(26,100,000)
Amortization	259,900,000	302,700,000
Deferred Tax Liabilities, Leasing Arrangements	(24,500,000)	(42,200,000)
Assets and liabilities from long-term manufacturing contracts and advances	(53,700,000)	(93,200,000)
Deferred Tax Liabilities, Undistributed Foreign Earnings	11,900,000	11,500,000
Other, net	(5,000,000.0)	(1,800,000)
Total deferred tax liabilities	(374,800,000)	(477,500,000)
Deferred tax liabilities, net	(170,500,000)	(297,300,000)
Amounts recorded in the Consolidated Balance Sheets:
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	19,500,000	17,000,000.0
Deferred tax liabilities, non-current	(190,000,000.0)	(314,300,000)
Deferred tax liabilities, net	(170,500,000)	(297,300,000)
Deferred income tax assets related to U.S. federal and state tax credit carryforwards	12,300,000	8,300,000
Deferred income tax assets related to foreign net operating loss carryforwards	24,900,000	44,000,000.0
Current income tax payable	57,700,000	16,500,000
Deferred Tax Liability, Unremitted Earnings of Foreign Subsidiaries	11,900,000	$ 11,500,000
Accrued Income Taxes, Noncurrent	$ 6,200,000