Costs and Estimated Earnings in Excess of Billings - Costs and Estimated Earnings in Excess of Billings (Detail) - USD ($)	Dec. 31, 2021	Sep. 30, 2021
Costs in Excess of Billings on Uncompleted Contracts or Programs [Abstract]
Costs incurred on uncompleted contracts	$ 17,429,000	$ 11,483,000
Estimated earnings	6,380,000	4,395,000
Costs and estimated earnings on uncompleted contracts	23,809,000	15,878,000
Billings to date	22,584,000	13,975,000
Costs and estimated earnings in excess of billings	$ 1,225,000	$ 1,903,000