Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Allowance for doubtful accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	$ 249	$ 592
Additions (Reductions) Charged to Expense	(91)	(80)
Additions (Reductions) Charged to Other Accounts	0	0
Deductions	9	(263)
Valuation allowances and reserves, ending balance	167	249
Inventory obsolescence reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	3,676	3,335
Additions (Reductions) Charged to Expense	(50)	518
Additions (Reductions) Charged to Other Accounts	(180)	(151)
Deductions	(2)	(26)
Valuation allowances and reserves, ending balance	3,444	3,676
Inventory LIFO reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	8,286	8,296
Additions (Reductions) Charged to Expense	924	(10)
Additions (Reductions) Charged to Other Accounts		0
Deductions		0
Valuation allowances and reserves, ending balance	9,210	8,286
Deferred tax valuation allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	5,329	7,557
Additions (Reductions) Charged to Expense	345	(2,362)
Additions (Reductions) Charged to Other Accounts	(1,033)	134
Deductions	0	0
Valuation allowances and reserves, ending balance	4,641	5,329
Workers’ compensation reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	546	181
Additions (Reductions) Charged to Expense	1,241	703
Additions (Reductions) Charged to Other Accounts	(53)	0
Deductions	(846)	(338)
Valuation allowances and reserves, ending balance	$ 888	$ 546