Revenue - Contract Balances (Details) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Change In Contract With Customer, Assets [Roll Forward]
Contract assets - Beginning balance	$ 10,091,000	$ 10,172,000	$ 10,172,000
Additional revenue recognized over-time	9,184,000	12,042,000
Less amounts billed to the customers	(8,326,000)	(10,692,000)
Contract assets - Ending balance	10,949,000	11,522,000	10,091,000
Change In Contract With Customer, Liability [Roll Forward]
Contract liabilities (included within Accrued liabilities) - Beginning balance	(1,150,000)	(807,000)	(807,000)
Payments received in advance of performance obligations	(1,753,000)	(1,401,000)
Performance obligations satisfied	20,000	426,000
Contract liabilities (included within Accrued liabilities) - Ending balance	(2,883,000)	(1,782,000)	(1,150,000)
Accounts receivable		$ 15,308,000		$ 16,515,000
Impairment loss on contract assets	$ 0		$ 0