Revolving Credit Facility - Components of Interest Expense (Details) - Line of Credit - Revolving Credit Facility - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Line of Credit Facility [Line Items]
Interest expense	$ 512	$ 1,041
Amortization of debt financing costs	282	155
Unused commitment fees	102	39
Total interest expense	896	$ 1,235
Write-off of unamortized deferred financing costs	$ 100