Supporting Financial Information - Other Income (Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest expense	$ (208)	$ (215)	$ (427)	$ (440)
Amortization of debt financing costs as interest expense	(67)	(67)	(132)	(127)
Change in fair value of derivative financial instruments	0	27	0	(52)
Other income (expense), net	14		20	0
Other income (expense) net	$ (261)	$ (255)	$ (539)	$ (619)