Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Allowance for doubtful accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	$ 330	$ 706
Additions (Reductions) Charged to Expense	415	77
Additions (Reductions) Charged to Other Accounts	(39)	8
Deductions	(186)	(461)
Valuation allowances and reserves, ending balance	520	330
Inventory obsolescence reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	3,859	3,308
Additions (Reductions) Charged to Expense	177	657
Additions (Reductions) Charged to Other Accounts	(30)	91
Deductions	(127)	(197)
Valuation allowances and reserves, ending balance	3,879	3,859
Inventory LIFO reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	8,319	8,026
Additions (Reductions) Charged to Expense	560	293
Additions (Reductions) Charged to Other Accounts	0	0
Deductions	0	0
Valuation allowances and reserves, ending balance	8,879	8,319
Deferred tax valuation allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	9,597	4,399
Additions (Reductions) Charged to Expense	(968)	6,117
Additions (Reductions) Charged to Other Accounts	(229)	(919)
Deductions	0	0
Valuation allowances and reserves, ending balance	8,400	9,597
Workers’ compensation reserve
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance	237	324
Additions (Reductions) Charged to Expense	(132)	234
Additions (Reductions) Charged to Other Accounts	0	1
Deductions	31	(322)
Valuation allowances and reserves, ending balance	$ 136	$ 237