Costs and Estimated Earnings in Excess of Billings - Costs and Estimated Earnings in Excess of Billings on Uncompleted Contracts (Detail) - USD ($)	Jun. 30, 2024	Sep. 30, 2023
Costs in Excess of Billings on Uncompleted Contracts or Programs [Abstract]
Costs incurred on uncompleted contracts	$ 11,950,000	$ 18,468,000
Estimated earnings	3,674,000	7,939,000
Costs and estimated earnings on uncompleted contracts	15,624,000	26,407,000
Billings to date	12,924,000	24,899,000
Costs and estimated earnings in excess of billings	$ 2,700,000	$ 1,508,000