Income Tax Expense - Schedule Of Actual Income Tax Expense (Benefit) From Continuing Operations (Details)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Tax Expense
Federal corporate statutory rate	21.00%	21.00%	21.00%
State and local, net of Federal benefits	2.10%	2.90%	1.90%
Impact of foreign operations	0.30%	(0.30%)	(0.40%)
Federal research credit	(1.10%)	(0.30%)	(0.90%)
Executive compensation	0.90%	0.50%	0.90%
Valuation allowance	0.30%	(0.30%)	0.00%
U.S. tax on GILTI	1.20%	1.80%	1.00%
Foreign tax credits	(0.90%)	(1.50%)	(0.60%)
FDII deduction	(1.60%)	(0.90%)	(1.70%)
Other, net	0.00%	(0.20%)	0.10%
Effective income tax rate	22.20%	22.70%	21.30%