Income Taxes - Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Current:
Federal tax (benefit) expense	$ (34)	$ 220	$ 668
State tax expense	446	189	351
Deferred:
Federal tax benefit	(3,018)	(487)	(685)
State tax (benefit) expense	(189)	(99)	3
Income tax (benefit) expense	$ (2,795)	$ (177)	$ 337