Contingencies - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2026	Sep. 30, 2025
Loss Contingencies [Line Items]
Standard product warranty length, minimum	1 year
Standard product warranty length, maximum	2 years
Limited product warranty length (up to)	10 years
Accrued amounts for litigation and other contingent liabilities	$ 27,607	$ 9,930
Performance Bonds
Loss Contingencies [Line Items]
Letters of credit secured using cash collateral	45,300
Outstanding performance bonds	364,300
Surety-backed letters of credit	$ 4,600