Inventories - Narrative (Details) - USD ($)	9 Months Ended		12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Inventory Disclosure [Abstract]
Proceeds from federal relief grants	$ 4,299,000	$ 15,597,000	$ 4,629,000	$ 4,629,000