Income Taxes - Schedule of Reconciliation of Actual Income Taxes to Income Taxes at Expected United States Federal Corporate Income Tax Rate (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Federal statutory rate	35.00%	21.00%	21.00%	24.30%
Tax (benefit) expense at the federal statutory rate		$ (3,146)	$ (784)	$ 1,342
Effect of permanent book-tax differences		145	272	75
State tax provision		34	31	76
Valuation allowance for net deferred tax assets		3,775	1,682	617
Uncertain tax items		(47)	74	(3,013)
Tax rate differential		222	150	1,107
Other items		(239)	5	16
Total provision		$ 744	$ 1,430	$ 220