Costs and Estimated Earnings in Excess of Billings - Costs and Estimated Earnings in Excess of Billings on Uncompleted Contracts (Detail) - USD ($)	Sep. 30, 2022	Sep. 30, 2021
Costs in Excess of Billings on Uncompleted Contracts or Programs [Abstract]
Costs incurred on uncompleted contracts	$ 12,660,000	$ 11,483,000
Estimated earnings	4,780,000	4,395,000
Costs and estimated earnings on uncompleted contracts	17,440,000	15,878,000
Billings to date	15,322,000	13,975,000
Costs and estimated earnings in excess of billings	$ 2,118,000	$ 1,903,000