Supporting Financial Information - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest expense	$ (696)	$ (635)	$ (2,367)	$ (2,229)
Amortization of deferred financing costs	(197)	(178)	(610)	(551)
Other income (expense), net	0	0	0	121
Interest expense, net	$ (893)	$ (813)	$ (2,977)	$ (2,659)