Inventories - Narrative (Details) - USD ($)	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Inventory Disclosure [Abstract]
Additional amount that would have been reported in inventory if FIFO method had been used	$ 9,210,000	$ 8,286,000
LIFO expense (benefit)	924,000	(10,000)
Cost of goods sold	$ 156,000	$ 0