Costs and Estimated Earnings in Excess of Billings - Costs and Estimated Earnings in Excess of Billings (Detail) - USD ($)	Mar. 31, 2022	Sep. 30, 2021
Costs in Excess of Billings on Uncompleted Contracts or Programs [Abstract]
Costs incurred on uncompleted contracts	$ 19,501,000	$ 11,483,000
Estimated earnings	5,875,000	4,395,000
Costs and estimated earnings on uncompleted contracts	25,376,000	15,878,000
Billings to date	23,747,000	13,975,000
Costs and estimated earnings in excess of billings	$ 1,629,000	$ 1,903,000