Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Apr. 02, 2021	Mar. 10, 2021	Sep. 30, 2020
Business Acquisition [Line Items]
Allowance for doubtful accounts	$ 0		$ 0				$ 0
Transaction costs	321,000	$ 15,000	3,374,000	$ 42,000
Unrecognized tax benefits	0		0				$ 0
Kansas Properties
Business Acquisition [Line Items]
Goodwill	$ 19,100,000		19,100,000			$ 19,100,000
Discontinued operation, carrying value						22,000,000.0
Discontinued operation, fair value						3,500,000
Goodwill, impairment loss			$ 18,500,000
Kansas Properties
Business Acquisition [Line Items]
Consideration					$ 3,500,000	$ 3,500,000