Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Effective Tax Rate Reconciliation
Statutory tax rate	21.00%	21.00%	21.00%
State and local income taxes	0.20%	1.50%	0.50%
Non-United States taxes	(4.20%)	(4.70%)	(5.40%)
Repatriation of foreign earnings	0.90%	0.90%	1.10%
Foreign-derived intangible income	(0.70%)	(0.60%)	(0.50%)
Settlements with taxing authorities and tax refund claims	(1.20%)	0.30%	0.00%
Change in valuation allowance	0.50%	4.10%	(0.50%)
Share-based compensation	(0.20%)	(0.60%)	(1.00%)
Research and development tax credit	(2.00%)	(1.30%)	(1.00%)
Other	(0.50%)	(0.10%)	0.20%
Effective income tax rate	13.80%	20.50%	14.40%