Employee Benefit Plans - Deferred Compensation Plans (Details) - USD ($)	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Deferred Compensation Arrangement with Individual, Excluding Share-Based Payments and Postretirement Benefits [Line Items]
Defined Contribution Plan, Cost	$ 1,600,000	$ 1,100,000	$ 1,000,000.0
Share-Based Compensation Arrangement by Share-Based Payment Award, Purchase Price of Common Stock, Percent	85.00%
Employee Stock Purchase Plan, Maximum Percent of Annual Compensation	15.00%
Fair Market Value Of Common Stock Available For Purchase To Eligible Employees Maximum	$ 25,000
Stock Issued During Period, Shares, Employee Stock Purchase Plans	14,822	6,941	0
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 300,000	$ 200,000
Salary and Wage, Officer, Excluding Cost of Good and Service Sold	$ 3,100,000
Employee Stock
Deferred Compensation Arrangement with Individual, Excluding Share-Based Payments and Postretirement Benefits [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	2,500,000
Share-Based Payment Arrangement
Deferred Compensation Arrangement with Individual, Excluding Share-Based Payments and Postretirement Benefits [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	2,100,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant	1,100,000
Supplemental Executive Retirement Plan
Deferred Compensation Arrangement with Individual, Excluding Share-Based Payments and Postretirement Benefits [Line Items]
Deferred Compensation Liability, Current and Noncurrent	$ 1,900,000
Deferred Compensation Arrangement with Individual, Compensation Expense	$ 600,000	$ 100,000