Contract Assets - Contract Assets Reflect Costs and Estimated Earnings in Excess of \Billings on Uncompleted Contracts (Detail) - USD ($)	Sep. 30, 2025	Sep. 30, 2024
Contract with Customer, Asset, after Allowance for Credit Loss [Abstract]
Costs incurred on uncompleted contracts	$ 17,360,000	$ 14,508,000
Estimated earnings	5,926,000	6,977,000
Costs and estimated earnings on uncompleted contracts	23,286,000	21,485,000
Billings to date	11,078,000	12,146,000
Contract assets	$ 12,208,000	$ 9,339,000