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Leases - Summary of Other Information Concerning the Company's Operating Lease (Detail) - USD ($) | Sep. 30, 2021 | Oct. 09, 2020 | Sep. 30, 2020 | Aug. 28, 2020
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Lessee, Lease, Description [Line Items] |  |  |  |
Operating lease ROU asset included in other long-term assets |  |  |  | $ 970,000
Current operating lease liability | $ 393,000 |  | $ 328,000 |
Non-current operating lease liability | 392,000 |  | 614,000 |
New Lease Agreement [Member] |  |  |  |
Lessee, Lease, Description [Line Items] |  |  |  |
Operating lease ROU asset included in other long-term assets |  | $ 254,000 |  |
Blaw Knox Product Line From Volvo CE [Member] | New Lease Agreement [Member] |  |  |  |
Lessee, Lease, Description [Line Items] |  |  |  |
Operating lease ROU asset included in other long-term assets | 785,000 |  | 942,000 |
Current operating lease liability | 393,000 |  | 328,000 |
Non-current operating lease liability | $ 392,000 |  | $ 614,000 |
Weighted average remaining lease term (in years) | 2 years |  | 2 years 11 months 1 day |
Weighted average discount rate used in calculating ROU asset | 4.00% |  | 4.00% |

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as current. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977 + Details
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease, classified as noncurrent. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977 + Details
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- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123391704&loc=SL77918627-209977 + Details
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- Definition Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 55 -Paragraph 53 -URI http://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (g)(3) -URI http://asc.fasb.org/extlink&oid=123408670&loc=SL77918686-209980 + Details
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