Leases - Supplemental Balance Sheet Information Schedule (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Sep. 30, 2020
Assets:
Property, plant and equipment, net	$ 48	$ 89
Operating lease right-of-use assets, net	16,174	17,021
Total lease assets	16,222	17,110
Current liabilities:
Current maturities of long-term debt	29	58
Short-term operating lease liabilities	800	991
Non-current liabilities:
Long-term debt, net of current maturities	7	22
Long-term operating lease liabilities, net of short-term	15,624	16,188
Total lease liabilities	$ 16,460	$ 17,259
Finance lease, asset, statement of financial position [Extensible List]	Property, plant and equipment, net	Property, plant and equipment, net
Current finance lease, liability, statement of financial position [Extensible List]	Current maturities of long-term debt	Current maturities of long-term debt
Noncurrent finance lease, liability, statement of financial position [Extensible List]	Total long-term debt	Total long-term debt