Summary of Significant Accounting Policies - Narrative (Details) $ in Thousands	12 Months Ended
Sep. 30, 2021 USD ($) customer shares	Sep. 30, 2020 USD ($) customer shares
Accounting Policies [Line Items]
Allowance for doubtful accounts	$ 167	$ 249
Accounts receivable, allowance for credit loss, recovery	9
Accounts receivable, written off		263
Bad debt benefit	$ 91	$ 80
Percentage of inventory estimated using LIFO method	39.00%	47.00%
Reserve for obsolete and excess inventory	$ 3,444	$ 3,676
Depreciation expense	$ 6,651	$ 5,883
Anti-dilutive weighted-average common shares excluded from calculation of diluted earnings per share (in shares) \| shares	412,000	207,000
Restricted shares
Accounting Policies [Line Items]
Anti-dilutive weighted-average common shares excluded from calculation of diluted earnings per share (in shares) \| shares	0	0
Minimum
Accounting Policies [Line Items]
Finite-lived intangible asset, useful life (in years)	1 year
Maximum
Accounting Policies [Line Items]
Finite-lived intangible asset, useful life (in years)	10 years
Building and Building Improvements \| Minimum
Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)	5 years
Building and Building Improvements \| Maximum
Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)	40 years
Machinery and Equipment \| Minimum
Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)	3 years
Machinery and Equipment \| Maximum
Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)	20 years
Computer Software \| Minimum
Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)	3 years
Computer Software \| Maximum
Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)	7 years
Leasehold Improvements \| Minimum
Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)	6 years
Leasehold Improvements \| Maximum
Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)	15 years
Customer Concentration Risk \| Sales Revenue, Net
Accounting Policies [Line Items]
Number of major customers \| customer	2	1
Customer Concentration Risk \| Sales Revenue, Net \| Total Customers and Their Subcontractors
Accounting Policies [Line Items]
Percentage of concentration risk	38.00%	49.00%
Number of major customers \| customer	3	4
Customer Concentration Risk \| Sales Revenue, Net \| Major Customer One and Their Subcontractors
Accounting Policies [Line Items]
Percentage of concentration risk	17.00%	16.00%
Customer Concentration Risk \| Sales Revenue, Net \| Major Customer Two and Their Subcontractors
Accounting Policies [Line Items]
Percentage of concentration risk	11.00%	13.00%
Customer Concentration Risk \| Sales Revenue, Net \| Major Customer Three and Their Subcontractors
Accounting Policies [Line Items]
Percentage of concentration risk	10.00%	10.00%
Customer Concentration Risk \| Sales Revenue, Net \| Major Customer Four and Their Subcontractors
Accounting Policies [Line Items]
Percentage of concentration risk		10.00%
Customer Concentration Risk \| Sales Revenue, Net \| Customer One
Accounting Policies [Line Items]
Percentage of concentration risk		10.00%
Customer Concentration Risk \| Sales Revenue, Net \| Two Largest Customers
Accounting Policies [Line Items]
Percentage of concentration risk	20.00%
Customer Concentration Risk \| Accounts Receivable
Accounting Policies [Line Items]
Number of major customers \| customer		1
Customer Concentration Risk \| Accounts Receivable \| Total Customers and Their Subcontractors
Accounting Policies [Line Items]
Number of major customers \| customer	1	3
Customer Concentration Risk \| Accounts Receivable \| Major Customer One and Their Subcontractors
Accounting Policies [Line Items]
Percentage of concentration risk	17.00%	13.00%
Customer Concentration Risk \| Accounts Receivable \| Major Customer Two and Their Subcontractors
Accounting Policies [Line Items]
Percentage of concentration risk		13.00%
Customer Concentration Risk \| Accounts Receivable \| Major Customer Three and Their Subcontractors
Accounting Policies [Line Items]
Percentage of concentration risk		12.00%
Customer Concentration Risk \| Accounts Receivable \| Customer One
Accounting Policies [Line Items]
Percentage of concentration risk		11.00%

Number of major customer.

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Amount of allowance for credit loss on accounts receivable.

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Amount of increase in allowance for credit loss on accounts receivable, from recovery.

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Amount of direct write-downs of accounts receivable charged against the allowance.

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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