Leases - Supplemental Balance Sheet Information Schedule (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020
ASSETS
Property, plant and equipment, net	$ 75	$ 89
Operating lease right-of-use assets, net	16,709	17,021
Total lease assets	16,784	17,110
Current liabilities:
Current maturities of long-term debt	56	58
Short-term operating lease liabilities	900	991
Non-current liabilities:
Long-term debt, net of current maturities	14	22
Long-term operating lease liabilities, net of short-term	16,003	16,188
Total lease liabilities	$ 16,973	$ 17,259
Finance lease, asset, statement of financial position [Extensible List]	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization	us-gaap:PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization
Current finance lease, liability, statement of financial position [Extensible List]	us-gaap:LongTermDebtCurrent	us-gaap:LongTermDebtCurrent
Noncurrent finance lease, liability, statement of financial position [Extensible List]	us-gaap:LongTermDebtNoncurrent	us-gaap:LongTermDebtNoncurrent