Goodwill and Other Intangible Assets, Net - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2017
Intangible Assets
Amortization of customer relationships, patents, non-competes and other intangibles	$ 131	$ 122	$ 264	$ 245
Total intangible assets, Gross Amount	10,221		10,221		$ 10,221
Finite-lived intangible assets, Accumulated Amortization	(4,419)		(4,419)		(4,155)
Carrying Amount	5,802		5,802		6,066
Patents
Intangible Assets
Finite-Lived Intangible Assets, Gross	4,030		4,030		4,030
Finite-lived intangible assets, Accumulated Amortization	(3,816)		(3,816)		(3,656)
Finite-lived intangible assets, Carrying Amount	214		214		374
Customer relationships
Intangible Assets
Finite-Lived Intangible Assets, Gross	2,100		2,100		2,100
Finite-lived intangible assets, Accumulated Amortization	(501)		(501)		(426)
Finite-lived intangible assets, Carrying Amount	1,599		1,599		1,674
Other Intangible Assets
Intangible Assets
Finite-Lived Intangible Assets, Gross	291		291		291
Finite-lived intangible assets, Accumulated Amortization	(102)		(102)		(73)
Finite-lived intangible assets, Carrying Amount	189		189		218
Trademarks
Intangible Assets
Indefinite-lived intangible assets	$ 3,800		$ 3,800		$ 3,800