Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands		12 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance		$ 333	$ 481	$ 500
Additions (Reductions) Charged to Expense		487	9	81
Additions (Reductions) Charged to Other Accounts		307	1	47
Deductions	[1]	0	(158)	(147)
Valuation allowances and reserves, ending balance		1,127	333	481
Inventory obsolescence reserve
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance		1,407	1,394	1,192
Additions (Reductions) Charged to Expense		138	131	520
Additions (Reductions) Charged to Other Accounts		1,804	(118)	(318)
Deductions	[2]	(327)	0	0
Valuation allowances and reserves, ending balance		3,022	1,407	1,394
Inventory LIFO reserve
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance		7,879	7,977	9,537
Additions (Reductions) Charged to Expense		629	(98)	(1,560)
Additions (Reductions) Charged to Other Accounts		0	0	0
Deductions		0	0	0
Valuation allowances and reserves, ending balance		8,508	7,879	7,977
Asset impairment reserve
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance		0	72	757
Additions (Reductions) Charged to Expense			0	72
Additions (Reductions) Charged to Other Accounts			(72)	0
Deductions	[3]		0	(757)
Valuation allowances and reserves, ending balance			0	72
Deferred tax valuation allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance		822	718	579
Additions (Reductions) Charged to Expense		273	104	139
Additions (Reductions) Charged to Other Accounts		0	0	0
Deductions		0	0	0
Valuation allowances and reserves, ending balance		1,095	822	718
Workers’ compensation reserve
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, beginning balance		937	744	663
Additions (Reductions) Charged to Expense		626	515	82
Additions (Reductions) Charged to Other Accounts		(326)	0	0
Deductions	[4]	(549)	(322)	(1)
Valuation allowances and reserves, ending balance		$ 688	$ 937	$ 744

[1] Accounts determined to be uncollectible, net of recoveries

[2] Inventory sold or otherwise disposed

[3] Equipment sold or otherwise disposed

[4] Payment of workers’ compensation claims