Supporting Financial Information - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest expense	$ (801)	$ (742)	$ (1,671)	$ (1,593)
Amortization of deferred financing costs	(203)	(164)	(413)	(374)
Other income (expense), net	0	0	0	121
Interest expense, net	$ (1,004)	$ (906)	$ (2,084)	$ (1,846)