Supporting Financial Information - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interest expense	$ (870)	$ (852)
Amortization of deferred financing costs	(210)	(210)
Other income (expense), net	0	121
Interest expense, net	$ (1,080)	$ (941)