Contract Assets - Contract Assets Reflect Costs and Estimated Earnings in Excess of \Billings on Uncompleted Contracts (Detail) - USD ($)	Sep. 30, 2024	Sep. 30, 2023
Contract with Customer, Asset, after Allowance for Credit Loss [Abstract]
Costs incurred on uncompleted contracts	$ 14,508,000	$ 18,468,000
Estimated earnings	6,977,000	7,939,000
Costs and estimated earnings on uncompleted contracts	21,485,000	26,407,000
Billings to date	12,146,000	24,899,000
Contract assets	$ 9,339,000	$ 1,508,000

Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479837/606-10-45-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479837/606-10-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479806/606-10-50-8

Name:	us-gaap_ContractWithCustomerAssetNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant