Retirement and Deferred Compensation Plan - Deferred Compensation Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accrued compensations and benefits	$ 57,781	$ 54,606
Deferred Compensation Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred compensation plan assets	3,200	2,700
Accrued compensations and benefits	5,500	7,200
Employer contribution to deferred compensation plan	$ 200	$ 200	$ 200