Pension and Other Post-Retirement Benefits - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plans, employer matching contribution, percentage	50.00%
Defined contribution plans, employer matching contribution of eligible salary, percentage	6.00%
Defined contribution plans, charges incurred	$ 0.5	$ 0.5	$ 0.5
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plans, pension expenses	0.3	0.5	0.5
Defined benefit plans, benefit obligation	12.2	11.8	10.4
Defined benefit plans, Net liability	6.2	$ 5.5	$ 4.9
Defined Benefit Plans, Settlement And Curtailment	$ 0.4

Amount of liability, recognized in statement of financial position, for defined benefit pension plan. Excludes other postretirement benefit plan.

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Amount of (increase) decrease in accumulated benefit obligation of defined benefit plan from effects of settlement and curtailment.

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- Definition

Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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Amount of cost for defined contribution plan.

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Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

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Percentage employer matches of the employee's percentage contribution matched.

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Amount of cost (reversal of cost) for pension benefits. Excludes other postretirement benefits.

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