Summary of Significant Accounting Policies - Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 07, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Intangible Assets
Goodwill impairment charges		$ 0	$ 0
Goodwill		4,789	4,789
Change to goodwill		0
Amortization of customer relationships, patents, non-competes and other intangibles		503	511	$ 416
Total intangible assets, Gross Amount		10,221	10,260
Finite-lived intangible assets, Accumulated Amortization		(3,659)	(3,486)
Carrying Amount		$ 6,562	6,774
Leveltek Processing, LLC
Intangible Assets
Acquisition price	$ 14,600
Goodwill	$ 4,789
Minimum
Intangible Assets
Useful life		2 years
Maximum
Intangible Assets
Useful life		16 years
Patents
Intangible Assets
Finite-lived intangible assets Gross Amount		$ 4,030	4,030
Finite-lived intangible assets, Accumulated Amortization		(3,370)	(3,091)
Finite-lived intangible assets, Carrying Amount		660	939
Customer relationships
Intangible Assets
Finite-lived intangible assets Gross Amount		2,100	2,100
Finite-lived intangible assets, Accumulated Amortization		(275)	(119)
Finite-lived intangible assets, Carrying Amount		1,825	1,981
Customer relationships | Leveltek Processing, LLC
Intangible Assets
Useful life	16 years
Customer relationships	$ 2,100
Other Intangible Assets
Intangible Assets
Finite-lived intangible assets Gross Amount		291	330
Finite-lived intangible assets, Accumulated Amortization		(14)	(276)
Finite-lived intangible assets, Carrying Amount		277	54
Trademarks
Intangible Assets
Indefinite-lived intangible assets		$ 3,800	$ 3,800