Credit Facilities - Summary of Loan Facility (Details) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2021	Sep. 30, 2020
Line of Credit Facility [Line Items]
Total bank debt obligation	$ 53,800
Secured Debt | Term Loans
Line of Credit Facility [Line Items]
Total bank debt obligation	$ 53,800	$ 70,000
Secured Debt | Term Loans | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate percentage	0.035%
Interest rate spread	0.09%
Interest rate floor	0.50%
Secured Debt | Revolving Line of Credit | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate percentage	0.035%
Interest rate spread	0.09%
Interest rate floor	0.50%