Commitments and Contingencies - Insurance Proceeds Impact On Consolidated Condensed Statements Of Operation (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Loss Contingencies [Line Items]
Loss (gain) on insurance recoveries	$ (5,874)	$ (7,253)
Cost of goods sold	93,611	101,817
Income (loss) before income tax benefit	8,980	(8,207)
Balance without insurance proceeds
Loss Contingencies [Line Items]
Cost of goods sold, balance without insurance proceeds	96,711	105,448
Loss (gain) on insurance recoveries	0	1,102
Income (loss) before income tax (benefit) expense, balance without insurance proceeds	6	(20,193)
Insurance recoveries
Loss Contingencies [Line Items]
Loss (gain) on insurance recoveries	(5,874)	(8,355)
Insurance recoveries | Cost of goods sold
Loss Contingencies [Line Items]
Loss (gain) on insurance recoveries	(3,100)	(3,631)
Insurance recoveries | Loss before income tax benefit
Loss Contingencies [Line Items]
Loss (gain) on insurance recoveries	$ (8,974)	$ (11,986)