Leases - Supplemental Balance Sheet Information Schedule (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
ASSETS
Property, plant and equipment, net	$ 34	$ 89
Operating lease right-of-use assets, net	15,943	17,021
Total lease assets	15,977	17,110
Current liabilities:
Current maturities of long-term debt	17	58
Short-term operating lease liabilities	788	991
Non-current liabilities:
Long-term debt, net of current maturities	5	22
Long-term operating lease liabilities, net of short-term	15,439	16,188
Total lease liabilities	$ 16,249	$ 17,259
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, plant and equipment, net	Property, plant and equipment, net
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Current maturities of long-term debt	Current maturities of long-term debt
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Total long-term debt	Total long-term debt