Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Allowance for doubtful accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	$ 520	$ 330
Additions (Reductions) Charged to Expense	39	415
Additions (Reductions) Charged to Other Accounts	0	(39)
Deductions	33	(186)
Valuation allowances and reserves, ending balance	592	520
Inventory obsolescence reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	3,879	3,859
Additions (Reductions) Charged to Expense	517	177
Additions (Reductions) Charged to Other Accounts	(106)	(30)
Deductions	(632)	(127)
Valuation allowances and reserves, ending balance	3,335	3,879
Inventory LIFO reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	8,879	8,319
Additions (Reductions) Charged to Expense	(75)	560
Additions (Reductions) Charged to Other Accounts	0	0
Deductions	0	0
Valuation allowances and reserves, ending balance	8,296	8,879
Deferred tax valuation allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	8,400	9,597
Additions (Reductions) Charged to Expense	(1,817)	(968)
Additions (Reductions) Charged to Other Accounts	974	(229)
Deductions		0
Valuation allowances and reserves, ending balance	7,557	8,400
Workers’ compensation reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	136	237
Additions (Reductions) Charged to Expense	395	(132)
Additions (Reductions) Charged to Other Accounts	0	0
Deductions	(350)	31
Valuation allowances and reserves, ending balance	181	136
Accounting Standards Update 2014-09 | Inventory obsolescence reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	3,556
Valuation allowances and reserves, ending balance		3,556
Accounting Standards Update 2014-09 | Inventory LIFO reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	$ 8,371
Valuation allowances and reserves, ending balance		$ 8,371