Leases - Balance Sheet Information (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Leases
Finance lease assets (included in Property, plant and equipment, net)	$ 5,643	$ 6,218
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization	Property, Plant, and Equipment and Finance Lease Right-of-Use Asset, after Accumulated Depreciation and Amortization
Operating right of use lease assets (included in Other assets)	$ 1,085	$ 1,494
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Prepaid Expenses and Deferred Costs, Noncurrent	Prepaid Expenses and Deferred Costs, Noncurrent
Finance lease liabilities
Accrued expenses	$ 265	$ 228
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued Liabilities, Current	Accrued Liabilities, Current
Long-term obligations (less current portion)	$ 7,119	$ 7,385
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Capital Leases Future Minimum Payments And Accrual For Environmental Loss Contingencies Noncurrent	Capital Leases Future Minimum Payments And Accrual For Environmental Loss Contingencies Noncurrent
Total Finance lease liabilities	$ 7,384	$ 7,613
Operating lease liabilities
Operating lease liabilities	$ 1,085	$ 1,494
Weighted average lease term Finance leases	13 years 1 month 6 days	14 years 1 month 6 days
Weighted average lease term Operating leases	3 years	2 years 6 months
Weighted average discount rate Finance leases (as a percent)	10.32%	10.32%
Weighted average discount rate Operating leases (as a percent)	5.25%	5.25%