0000080420-23-000051 | 10-K | XBRL Viewer

Print Document View Excel Document

Commitments and Contingencies - Narrative (Details) - USD ($)	3 Months Ended			12 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2023
Guarantor Obligations [Line Items]
Additional bonding capacity	$ 556,600,000			$ 556,600,000
Cash collateral requirement for guarantees				2 years
Probable liquidated damages				$ 2,700,000
Loss contingency, estimate of actual or projected loss	3,900,000			3,900,000
Failure to meet contractual commitments, reduction to revenue	1,000,000.0	$ 1,700,000	$ 1,600,000	700,000
Facility Agreement \| Powell (UK) Limited
Guarantor Obligations [Line Items]
Guarantee liability, letters of credit	7,600,000			7,600,000
Revolving credit facility	9,800,000			9,800,000
Amount of credit facility remaining borrowing capacity	2,200,000			2,200,000
Surety Bond
Guarantor Obligations [Line Items]
Guarantee liability, letters of credit	$ 393,400,000			$ 393,400,000

Leases

12 Months Ended

Sep. 30, 2023

Leases [Abstract]

Leases

Our leases consist primarily of office space and construction equipment. All of our future lease obligations are related to non-cancelable operating leases. The decrease of our lease portfolio relates to the wind down of our Canadian facility leases. The following table provides a summary of lease cost components for the years ended September 30, 2023, 2022 and 2021 respectively (in thousands):


Lease Cost	2023		2022		2021
Operating lease cost	$	1,457	$	2,146	$	2,435
Less: sublease income	(515)		(685)		(706)
Variable lease cost(1)	369		457		443
Short-term lease cost(2)	1,864		1,643		1,281
Total lease cost	$	3,175	$	3,561	$	3,453

(1) Variable lease cost represents common area maintenance charges related to our Canadian office space lease.
(2) Short-term lease cost includes leases and rentals with initial terms of one year or less.

We recognize operating lease assets and operating lease liabilities representing the present value of the remaining lease payments for leases with initial terms greater than twelve months. Leases with initial terms of twelve months or less are not recorded in our Consolidated Balance Sheets. The following table provides a summary of the operating lease assets and operating lease liabilities included in our Consolidated Balance Sheets as of September 30, 2023 and 2022, respectively (in thousands):


	September 30,
Operating Leases	2023		2022
Assets:
Operating lease assets, net	$	1,436	$	2,179

Liabilities:
Current operating lease liabilities	773		1,777
Long-term operating lease liabilities	663		545
Total lease liabilities	$	1,436	$	2,322

The following table provides the maturities of our operating lease liabilities as of September 30, 2023 (in thousands):


	Operating Leases
2024	$	802
2025	359
2026	169
2027	142
2028	18
Thereafter	—
Total future minimum lease payments	$	1,490
Less: present value discount (imputed interest)	(54)
Present value of lease liabilities	$	1,436

The weighted average discount rate as of September 30, 2023 and 2022 was 3.32% and 3.73%, respectively. The weighted average remaining lease term was 2.67 years and 1.51 years, respectively, at September 30, 2023 and 2022.

Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Revenue	$ 699,308	$ 532,582	$ 470,559
Oil and gas (excludes petrochemical)
Disaggregation of Revenue [Line Items]
Revenue	273,117	215,235	187,660
Petrochemical
Disaggregation of Revenue [Line Items]
Revenue	94,188	66,538	58,986
Electric utility
Disaggregation of Revenue [Line Items]
Revenue	158,400	122,361	111,244
Traction power
Disaggregation of Revenue [Line Items]
Revenue	28,112	44,930	59,106
Commercial and other industrial
Disaggregation of Revenue [Line Items]
Revenue	103,966	56,448	27,065
All others
Disaggregation of Revenue [Line Items]
Revenue	41,525	27,070	26,498
United States
Disaggregation of Revenue [Line Items]
Revenue	557,934	404,973	351,422
Canada
Disaggregation of Revenue [Line Items]
Revenue	84,090	81,218	68,655
Middle East and Africa
Disaggregation of Revenue [Line Items]
Revenue	14,998	20,712	26,615
Asia/Pacific
Disaggregation of Revenue [Line Items]
Revenue	6,188	4,885	8,889
Europe
Disaggregation of Revenue [Line Items]
Revenue	26,699	17,699	13,027
Mexico, Central and South America
Disaggregation of Revenue [Line Items]
Revenue	$ 9,399	$ 3,095	$ 1,951

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended	12 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Tax Contingency [Line Items]
Effective tax rate				21.00%	(40.00%)	42.00%
Net deferred tax assets	$ 17,064			$ 17,064	$ 9,161
Valuation allowance related to deferred tax assets	1,967			1,967	3,787
Income tax benefit				(14,425)	3,894	$ (461)
Undistributed earnings of foreign subsidiaries	17,900			17,900
Increase in valuation allowance	1,900	$ (5,900)		1,800
Unrecognized tax benefits, if recognized, would impact the effective tax rate	1,600			1,600	$ 1,100	1,100
Decrease in unrecognized tax benefits is reasonably possible	600			600
International
Income Tax Contingency [Line Items]
Valuation allowance related to deferred tax assets						$ 100
Operating loss carryforwards	6,800			6,800
International \| United Kingdom
Income Tax Contingency [Line Items]
Net deferred tax assets	$ 1,900			1,900
Income tax benefit				$ (1,900)
International \| Canada
Income Tax Contingency [Line Items]
Net deferred tax assets			$ 5,900
Income tax benefit			$ 5,900

Revenue

12 Months Ended

Sep. 30, 2023

Revenue from Contract with Customer [Abstract]

Revenue

Revenue Recognition

Our revenues are primarily generated from the manufacturing of custom-engineered products and systems under long-term fixed-price contracts under which we agree to manufacture various products such as traditional and arc-resistant distribution switchgear and control gear, medium-voltage circuit breakers, monitoring and control communications systems, motor control centers, switches and bus duct systems. These products may be sold separately as an engineered solution but are typically integrated into custom-built enclosures which we also build. These enclosures are referred to as power control room substations (PCRs®), custom-engineered modules or electrical houses (E-Houses). Some contracts may also include the installation and the commissioning of these enclosures.

Revenue from these contracts is generally recognized over time utilizing the cost-to-cost method. Under the cost-to-cost method, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. We believe that this method is the most accurate representation of our performance because it directly measures the value of the services transferred to the customer over time as we incur costs on our contracts. Contract costs include all direct materials, labor and indirect costs related to contract performance, which may include indirect labor, supplies, tools, repairs and depreciation costs.

We also have contracts to provide field service inspection, installation, commissioning, modification, and repair services, as well as retrofit and retrofill components for existing systems. If the service contract terms give us the right to invoice the customer for an amount that corresponds directly with the value of our performance completed to date (i.e., a service contract in which we bill a fixed amount for each hour of service provided), then we recognize revenue over time in each reporting period corresponding to the amount that we have the right to invoice. Our performance obligations are satisfied as the work progresses. Revenues from our custom-engineered products and value-added services transferred to customers over time accounted for approximately 94% of revenues for each of the years ended September 30, 2023 and September 30, 2022.

We also have sales orders for spare parts and replacement circuit breakers for switchgear that are obsolete or that are no longer produced by the original manufacturer. Revenues from these sales orders are recognized at the time we fulfill our performance obligation to the customer, which is typically upon shipment and represented approximately 6% of revenues for each of the years ended September 30, 2023 and September 30, 2022.

Additionally, some contracts may contain a cancellation clause that could limit the amount of revenue we are able to recognize over time. In these instances, revenue and costs associated with these contracts are deferred and recognized at a point in time when the performance obligation is fulfilled.

Selling and administrative costs incurred in relation to obtaining a contract are typically expensed as incurred. We periodically utilize a third-party sales agent to obtain a contract and will pay a commission to that agent. We record the full commission liability to the third-party sales agents at the order date, with a corresponding deferred asset. As the project progresses, we record commission expense based on percentage of completion rates that correlate to the project and reduce the deferred asset. Once we have been paid by the customer, we pay the commission, and the deferred liability is reduced.

Performance Obligations

A performance obligation is a promise in a contract or with a customer to transfer a distinct good or service. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue as the performance obligations are satisfied. To determine the proper revenue recognition for contracts, we evaluate whether a contract should be accounted for as more than one performance obligation or, less commonly, whether two or more contracts should be combined and accounted for as one performance obligation. This evaluation of performance obligations requires significant judgment. The majority of our contracts have a single performance obligation where multiple engineered products and services are combined into a single custom-engineered solution. Our contracts include a standard one-year assurance warranty. Occasionally, we provide service-type warranties that will extend the warranty period. These extended warranties qualify as a separate performance obligation, and revenue is deferred and recognized over the warranty period. If we determine during the evaluation of the contract that there are multiple performance obligations, we allocate the transaction price to each performance obligation using our best estimate of the standalone selling price of each distinct good or service in the contract.

Remaining unsatisfied performance obligations, which we refer to as backlog, represent the estimated transaction price for goods and services for which we have a material right, but work has not been performed. As of September 30, 2023, we had backlog of $1.3 billion, of which approximately $648.0 million is expected to be recognized as revenue within the next twelve months. Backlog may not be indicative of future operating results as orders may be cancelled or modified by our customers. Our backlog does not include service and maintenance-type contracts for which we have the right to invoice as services are performed.

Contract Estimates

Actual revenues and project costs may vary from previous estimates due to changes in a variety of factors. The cost estimation process is based upon the professional knowledge and experience of our engineers, project managers and financial professionals. Factors that are considered in estimating the work to be completed and ultimate contract recovery include the availability and productivity of labor, the nature and complexity of the work to be performed, the availability of materials, and the effect of any delays on our project performance. We periodically review our job performance, job conditions, estimated profitability and final contract settlements, including our estimate of total costs and make revisions to costs and income in the period in which the revisions are probable and reasonably estimable. We bear the risk of cost overruns in most of our contracts, which may result in reduced profits. Whenever revisions of estimated contract costs and contract values indicate that the contract costs will exceed estimated revenues, thus creating a loss, a provision for the total estimated loss is recorded in that period.

For the years ended September 30, 2023 and 2022, our operating results were positively impacted by $13.6 million and $11.3 million, respectively, as a result of changes in contract estimates related to projects in progress at the beginning of the respective period. These changes in estimates resulted primarily from favorable project execution, reduced cost estimates and negotiations of variable consideration, discussed below, as well as revenue recognized from project cancellations and other changes in facts and circumstances during these periods. Project cancellations on four projects increased gross profit for the year ended September 30, 2023 by $4.3 million. Gross unfavorable changes in contract estimates were immaterial for the years ended September 30, 2023 and 2022.

Variable Consideration

It is common for our long-term contracts to contain variable consideration that can either increase or decrease the transaction price. Due to the nature of our contracts, estimating total cost and revenue can be complex and subject to variability due to change orders, back charges, spare parts, early completion bonuses, customer allowances and liquidated damages. We estimate the amount of variable consideration based on the expected value method, which is the sum of the probability-weighted amounts, or the most likely amount method which uses various factors including experience with similar transactions and assessment of our anticipated performance. Variable consideration is included in the transaction price if legally enforceable and to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur once the uncertainty associated with the variable consideration is resolved.

Contract Modifications

Contracts may be modified for changes in contract specifications and requirements. We consider contract modifications to exist when the modification either creates new or changes the enforceable rights and obligations under the contract. Most of our contract modifications are for goods and services that are not distinct from the existing performance obligation. Contract modifications result in a cumulative catch-up adjustment to revenue based on our measure of progress for the performance obligation.

Contract Balances

The timing of revenue recognition, billings and cash collections affects accounts receivable, contract assets and contract liabilities in our Consolidated Balance Sheets.

Contract assets are recorded when revenues are recognized in excess of amounts billed for fixed-price contracts as determined by the billing milestone schedule. Contract assets are transferred to accounts receivable when billing milestones have been met, or we have an unconditional right to payment.

Contract liabilities typically represent advance payments from contractual billing milestones and billings in excess of revenue recognized. It is unusual to have advanced milestone payments with a term greater than one year, which could represent a financing component on the contract.

Our contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period and are generally classified as current.

Contract assets and liabilities as of September 30, 2023 and September 30, 2022 are summarized below (in thousands):


	September 30,
	2023		2022
Contract assets	$	60,621	$	88,351
Contract liabilities	(279,796)		(79,857)
Net contract asset (liability)	$	(219,175)	$	8,494

Our net contract billing position improved to a net liability at September 30, 2023 from a net asset position at September 30, 2022 primarily due to favorable contract billing milestones. We typically allocate a significant percentage of the progress billing to the early stages of the contract. These favorable billing milestones along with our increase in project backlog are driving the increase in the net contract liability at September 30, 2023. To determine the amount of revenue recognized during the period from contract liabilities, we first allocate revenue to the individual contract liability balance outstanding at the beginning of the period until the revenue exceeds that balance. During the year ended September 30, 2023, we recognized revenue of approximately $70.5 million related to contract liabilities outstanding at September 30, 2022.

The timing of our invoice process is typically dependent on the completion of certain milestones and contract terms and subject to agreement by our customer. Payment is typically expected within 30 days of invoice. Any uncollected invoiced amounts for our performance obligations recognized over time, including contract retentions, are recorded as accounts receivable in the Consolidated Balance Sheets. Certain contracts allow customers to withhold a small percentage of billings pursuant to retainage provisions, and such amounts are generally due upon completion of the contract and acceptance of the project by the customer. Based on our experience in recent years, the majority of these retainage balances are expected to be collected within approximately twelve months. As of September 30, 2023 and September 30, 2022, we had retention amounts of $7.4 million and $6.9 million, respectively. Of the retained amount at September 30, 2023, $7.2 million is expected to be collected in the next twelve months and is recorded in accounts receivable. The remaining $0.2 million is recorded in other assets.

Disaggregation of Revenue

The following tables present our disaggregated revenue by geographic destination and market sector for the years ended September 30, 2023, 2022 and 2021 (in thousands):


	2023		2022		2021
United States	$	557,934	$	404,973	$	351,422
Canada	84,090		81,218		68,655
Middle East and Africa	14,998		20,712		26,615
Asia/Pacific	6,188		4,885		8,889
Europe	26,699		17,699		13,027
Mexico, Central and South America	9,399		3,095		1,951
Total revenues by geographic destination	$	699,308	$	532,582	$	470,559


	2023		2022		2021
Oil and gas (excludes petrochemical)	$	273,117	$	215,235	$	187,660
Petrochemical	94,188		66,538		58,986
Electric utility	158,400		122,361		111,244
Traction power	28,112		44,930		59,106
Commercial and other industrial	103,966		56,448		27,065
All others	41,525		27,070		26,498
Total revenues by market sector	$	699,308	$	532,582	$	470,559

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-9

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-10

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-15

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 12
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-12

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-13

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Topic 606
-Publisher FASB
-URI https://asc.fasb.org//606/tableOfContent

+ Details

Leases (Tables)

12 Months Ended

Sep. 30, 2023

Leases [Abstract]

Lease Cost

The following table provides a summary of lease cost components for the years ended September 30, 2023, 2022 and 2021 respectively (in thousands):


Lease Cost	2023		2022		2021
Operating lease cost	$	1,457	$	2,146	$	2,435
Less: sublease income	(515)		(685)		(706)
Variable lease cost(1)	369		457		443
Short-term lease cost(2)	1,864		1,643		1,281
Total lease cost	$	3,175	$	3,561	$	3,453

(1) Variable lease cost represents common area maintenance charges related to our Canadian office space lease.
(2) Short-term lease cost includes leases and rentals with initial terms of one year or less.

Summary of Operating Lease Assets And Liabilities

The following table provides a summary of the operating lease assets and operating lease liabilities included in our Consolidated Balance Sheets as of September 30, 2023 and 2022, respectively (in thousands):


	September 30,
Operating Leases	2023		2022
Assets:
Operating lease assets, net	$	1,436	$	2,179

Liabilities:
Current operating lease liabilities	773		1,777
Long-term operating lease liabilities	663		545
Total lease liabilities	$	1,436	$	2,322

Maturities of Operating Lease Liabilities

The following table provides the maturities of our operating lease liabilities as of September 30, 2023 (in thousands):


	Operating Leases
2024	$	802
2025	359
2026	169
2027	142
2028	18
Thereafter	—
Total future minimum lease payments	$	1,490
Less: present value discount (imputed interest)	(54)
Present value of lease liabilities	$	1,436

Income Taxes - Schedule of Income Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
U.S.	$ 56,923	$ 3,175	$ 3,076
Foreign	12,027	6,668	(1,984)
Income before income taxes	$ 68,950	$ 9,843	$ 1,092

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(11))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 235
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-05(b)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479557/942-235-S99-1

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 25
-Paragraph 1
-SubTopic 20
-Topic 940
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481913/940-20-25-1

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(10))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(15))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

Stock-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended			12 Months Ended
	Feb. 15, 2023	Feb. 28, 2023	Feb. 28, 2022	Feb. 28, 2014	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
2014 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized plan extension period	5 years
Number of additional shares authorized (in shares)	600,000
Number of shares authorized (in shares)	1,350,000
2014 Director Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized plan extension period			10 years
Number of additional shares authorized (in shares)			200,000
Number of shares authorized (in shares)			350,000
Common stock, capital shares reserved for future issuance (in shares)					190,600
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense					$ 0.6	$ 0.4	$ 0.5
Weighted average remaining contractual life					6 months
Restricted Stock \| 2014 Director Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted stock outstanding (in shares)					8,400	7,200
Maximum number of shares granted to any individual (in shares)				12,000
Number of shares issued to any individual (in shares)				4,000
Restricted stock issuable to eligible Board of Directors members annually (in shares)				2,400
Shares issued under the plan (in shares)		16,800	16,800
Shares issued, price per share (in dollars per share)		$ 43.22	$ 23.09
Restricted Stock \| 2014 Director Plan \| Vesting of First Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				50.00%
Restricted Stock \| 2014 Director Plan \| Vesting of Second Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				50.00%
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted stock outstanding (in shares)					292,497	239,862
Compensation expense					$ 4.0	$ 3.7	$ 2.0
Amounts not yet recognized related to non-vested stock totaled					$ 1.4	$ 1.2
Weighted average remaining contractual life					1 year 6 months
Restricted Stock Units (RSUs) \| 2014 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				3 years
Restricted Stock Units (RSUs) \| 2014 Equity Incentive Plan \| Time Based Restricted Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				3 years
Restricted Stock Units (RSUs) \| 2014 Equity Incentive Plan \| Performance Based Restricted Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				3 years
Minimum \| Restricted Stock Units (RSUs) \| 2014 Equity Incentive Plan \| Time Based Restricted Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Actual amount of RSUs earned based on cumulative earnings				50.00%
Maximum \| Restricted Stock Units (RSUs) \| 2014 Equity Incentive Plan \| Performance Based Restricted Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Target RSUs granted range				50.00%

Detail of Selected Balance Sheet Accounts

12 Months Ended

Sep. 30, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Detail of Selected Balance Sheet Accounts

Inventories

The components of inventories are summarized below (in thousands):


	September 30,
	2023		2022
Raw materials, parts and sub-assemblies	$	68,631	$	54,220
Work-in-progress	1,379		1,202
Provision for excess and obsolete inventories	(6,145)		(5,007)
Total inventories	$	63,865	$	50,415

Property, Plant and Equipment

Property, plant and equipment are summarized below (in thousands):


	September 30,				Range of
	2023		2022		Asset Lives
Land	$	21,526	$	21,299	—
Buildings and improvements	121,454		120,506		3 – 39 Years
Machinery and equipment	92,477		88,213		3 – 15 Years
Furniture and fixtures	3,726		3,581		3 – 10 Years
Construction in process	4,129		1,728		—
	$	243,312	$	235,327
Less: Accumulated depreciation	(145,687)		(136,699)
Total property, plant and equipment, net	$	97,625	$	98,628

There were no assets under finance lease as of September 30, 2023 or September 30, 2022. Depreciation expense was $8.6 million, $9.4 million and $10.2 million for fiscal years 2023, 2022, and 2021, respectively.

Accrued Product Warranty

Activity in our product warranty accrual consisted of the following (in thousands):


	September 30,
	2023		2022
Balance at beginning of period	$	2,345	$	2,531
Increase to warranty expense	3,752		1,425
Deduction for warranty charges	(2,800)		(1,564)
Change due to foreign currency translation	8		(47)
Balance at end of period	$	3,305	$	2,345

Income Taxes - Schedule of Components of Deferred Income Tax Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Gross assets	$ 20,522	$ 17,941
Gross liabilities and valuation allowance	(3,458)	(8,780)
Net deferred income tax asset	$ 17,064	$ 9,161

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income/(Loss)
Beginning balance (in shares) at Sep. 30, 2020		12,422,000
Beginning balance, Treasury stock (in shares) at Sep. 30, 2020					(806,000)
Beginning balance at Sep. 30, 2020	$ 306,626	$ 124	$ 61,998	$ 294,016	$ (24,999)	$ (24,513)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	631			631
Foreign currency translation adjustments	4,253					4,253
Stock-based compensation (in shares)		76,000
Stock-based compensation	2,583	$ 1	2,582
Shares withheld in lieu of employee tax withholding	(632)		(632)
Dividends	(12,142)			(12,142)
Gain (loss) on cash flow commodity hedge	0
Postretirement benefit adjustment, net of tax	(96)					(96)
Ending balance (in shares) at Sep. 30, 2021		12,498,000
Ending balance, Treasury stock (in shares) at Sep. 30, 2021					(806,000)
Ending balance at Sep. 30, 2021	301,223	$ 125	63,948	282,505	$ (24,999)	(20,356)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	13,737			13,737
Foreign currency translation adjustments	(8,689)					(8,689)
Stock-based compensation (in shares)		90,000
Stock-based compensation	4,090	$ 1	4,089
Shares withheld in lieu of employee tax withholding	(675)		(675)
Dividends	(12,527)		77	(12,604)
Gain (loss) on cash flow commodity hedge	(325)					(325)
Postretirement benefit adjustment, net of tax	$ 372					372
Ending balance (in shares) at Sep. 30, 2022	12,588,011	12,588,000
Ending balance, Treasury stock (in shares) at Sep. 30, 2022	(806,018)				(806,000)
Ending balance at Sep. 30, 2022	$ 297,206	$ 126	67,439	283,638	$ (24,999)	(28,998)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	54,525			54,525
Foreign currency translation adjustments	1,915					1,915
Stock-based compensation (in shares)		80,000
Stock-based compensation	4,599	$ 1	4,598
Shares withheld in lieu of employee tax withholding	(652)		(652)
Dividends	(12,741)		141	(12,882)
Gain (loss) on cash flow commodity hedge	325					325
Postretirement benefit adjustment, net of tax	$ (151)					(151)
Ending balance (in shares) at Sep. 30, 2023	12,668,001	12,668,000
Ending balance, Treasury stock (in shares) at Sep. 30, 2023	(806,018)				(806,000)
Ending balance at Sep. 30, 2023	$ 345,026	$ 127	$ 71,526	$ 325,281	$ (24,999)	$ (26,909)

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Letters of Credit, Bank Guarantees and Bonds Certain customers require us to post letters of credit, bank guarantees or surety bonds. These security instruments assure that we will perform under the terms of our contract. In the event of default, the counterparty may demand payment from the bank under a letter of credit or bank guarantee, or performance by the surety under a bond. To date, there have been no significant draws or claims related to security instruments for the periods reported. We were contingently liable for letters of credit of $89.1 million as of September 30, 2023. We also had outstanding surety bonds totaling $393.4 million, with additional bonding capacity of $556.6 million available, at September 30, 2023. We have strong surety relationships; however, a change in market conditions or the sureties' assessment of our financial position could cause the sureties to require cash collateralization for undischarged liabilities under the bonds. We have a $9.8 million facility agreement (Facility Agreement) between Powell (UK) Limited and a large international bank that provides Powell (UK) Limited the ability to enter into bank guarantees as well as forward exchange contracts and currency options. At September 30, 2023, we had outstanding guarantees totaling $7.6 million, with additional capacity of $2.2 million available under this Facility Agreement. The Facility Agreement provides for customary events of default and carries cross-default provisions with the U.S. Revolver. If an event of default (as defined in the Facility Agreement) occurs and is continuing, per the terms and subject to the conditions set forth therein, obligations outstanding under the Facility Agreement may be accelerated and declared immediately due and payable. Additionally, we are required to maintain cash collateral for guarantees greater than two years. As of September 30, 2023, we were in compliance with all of the financial covenants of the Facility Agreement. Litigation We are involved in various legal proceedings, claims and other disputes arising from our commercial operations, projects, employees and other matters which, in general, are subject to uncertainties and in which the outcomes are not predictable. Although we can give no assurances about the resolution of pending claims, litigation or other disputes, and the effect such outcomes may have on us, management believes that any ultimate liability resulting from the outcome of such proceedings, to the extent not otherwise provided or covered by insurance, will not have a material adverse effect on our consolidated financial position, results of operations or liquidity. Liquidated Damages Certain of our customer contracts have schedule and performance obligation clauses that, if we fail to meet them, could require us to pay liquidated damages. Each individual contract defines the conditions under which the customer may make a claim against us. As of September 30, 2023, certain contracts had a probable exposure to liquidated damages of $2.7 million, which could possibly increase to $3.9 million under certain circumstances. Based on our actual or projected failure to meet these various contractual commitments, $0.7 million has been recorded as a reduction to revenue. We will attempt to obtain change orders, contract extensions or accelerate project completion, which may resolve the potential for any unrecorded liquidated damage. Should we fail to achieve relief on some or all of these contractual obligations, we could be required to pay additional liquidated damages, which could negatively impact our future operating results.

Detail of Selected Balance Sheet Accounts (Tables)

12 Months Ended

Sep. 30, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Components of Inventories

The components of inventories are summarized below (in thousands):


	September 30,
	2023		2022
Raw materials, parts and sub-assemblies	$	68,631	$	54,220
Work-in-progress	1,379		1,202
Provision for excess and obsolete inventories	(6,145)		(5,007)
Total inventories	$	63,865	$	50,415

Schedule of Property, Plant and Equipment

Property, plant and equipment are summarized below (in thousands):


	September 30,				Range of
	2023		2022		Asset Lives
Land	$	21,526	$	21,299	—
Buildings and improvements	121,454		120,506		3 – 39 Years
Machinery and equipment	92,477		88,213		3 – 15 Years
Furniture and fixtures	3,726		3,581		3 – 10 Years
Construction in process	4,129		1,728		—
	$	243,312	$	235,327
Less: Accumulated depreciation	(145,687)		(136,699)
Total property, plant and equipment, net	$	97,625	$	98,628

Activity in Product Warranty Accrual

Activity in our product warranty accrual consisted of the following (in thousands):


	September 30,
	2023		2022
Balance at beginning of period	$	2,345	$	2,531
Increase to warranty expense	3,752		1,425
Deduction for warranty charges	(2,800)		(1,564)
Change due to foreign currency translation	8		(47)
Balance at end of period	$	3,305	$	2,345

Summary of Significant Accounting Policies

12 Months Ended

Sep. 30, 2023

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Principles of Consolidation

The consolidated financial statements include the accounts of Powell and our wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States (U.S. GAAP) requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying footnotes. The most significant estimates used in our consolidated financial statements affect revenue recognition and estimated cost recognition on our customer contracts, the allowance for credit losses, provision for excess and obsolete inventory, warranty accruals and income taxes. The amounts recorded for warranties, legal, income taxes, impairment of long-lived assets (when applicable), liquidated damages and other contingent liabilities require judgments regarding the amount of expenses that will ultimately be incurred. We base our estimates on historical experience, forecasts and various other assumptions, as well as the specific circumstances surrounding these contingent liabilities, in evaluating the amount of liability that should be recorded. Additionally, the recognition of deferred tax assets requires estimates related to future income and other assumptions regarding timing and future profitability because the ultimate realization of net deferred tax assets is dependent on the generation of future taxable income during periods in which temporary differences become deductible. Estimates routinely change as new events occur, additional information becomes available or operating environments change. Actual results may differ from our prior estimates.

Cash and Investments

Cash and cash equivalents – Cash and cash equivalents, primarily funds held in money market savings instruments, are reported at their current carrying value, which approximates fair value due to the short-term nature of these instruments, and are included in cash and cash equivalents in our Consolidated Balance Sheets.

Short-term Investments – Short-term investments include time deposits with original maturities of three months or more.

Supplemental Disclosures of Cash Flow Information (in thousands):


	Year Ended September 30,
	2023		2022		2021
Cash paid (received) during the period for:
Interest received, net of interest expense	$	(5,465)	$	(334)	$	(73)
Income taxes paid, net of refunds	17,232		533		1,886
Non-cash capital expenditures	183		1,133		226

Fair Value of Financial Instruments

Financial instruments include cash, cash equivalents, short-term investments, receivables, deferred compensation, payables and debt obligations. Except as described below, due to the short-term nature of account receivables and account payables, their book values are representative of their fair values.

Accounts Receivable

Accounts receivable are stated net of allowances for credit losses. We maintain and continually assess the adequacy of the allowance for credit losses representing our estimate for losses resulting from the inability of our customers to pay amounts due to us. This estimated allowance is based on historical experience of uncollected accounts, the level of past due accounts, the overall level of outstanding accounts receivable, information about specific customers with respect to their inability to make payments and expectations of future conditions that could impact the collectability of accounts receivable. Future changes in our customers’ operating performance and cash flows, or in general economic conditions, could have an impact on their ability to fully pay these amounts, which could have a material impact on our operating results. In most cases, receivables are not collateralized. However, we utilize letters of credit to secure payment on projects when possible. Retention amounts are in accordance with applicable provisions of contracts and become due upon completion of contractual requirements. As of September 30, 2023 and 2022, we had retention amounts of $7.4 million and $6.9 million, respectively. Of the retained amount at September 30, 2023, $7.2 million is expected to be collected in the next twelve months and is recorded in accounts receivable. The remaining $0.2 million is recorded in other assets and is expected to be collected in the fiscal year ending September 30, 2025.

Contract Balances

The timing of revenue recognition, billings and cash collections affects accounts receivable, contract assets and contract liabilities in our Consolidated Balance Sheets.

Our contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period and are generally classified as current.

Inventories

Inventories are stated at the lower of cost or net realizable value using weighted-average methods and include the cost of materials, labor and manufacturing overhead. We use estimates in determining the level of reserves required to state inventory at the lower of cost or net realizable value. Our estimates are based on market activity levels, production requirements, the physical condition of products and technological innovation. Changes in any of these factors may result in adjustments to the carrying value of inventory.

Property, Plant and Equipment

Property, plant and equipment are stated at cost and are depreciated using the straight-line method over the estimated useful lives of the assets. Expenditures for repairs and maintenance are charged to expense when incurred. Expenditures for major renewals and improvements, which extend the useful lives of existing equipment, are capitalized and depreciated. Upon retirement or disposition of property, plant and equipment, the cost and related accumulated depreciation are removed from the accounts, and any resulting gain or loss is recognized in the Consolidated Statements of Operations.

We review property, plant and equipment for impairment whenever events or changes in circumstances indicate that the carrying value may not be realizable. If an evaluation is required, the estimated future undiscounted cash flows associated with the asset are compared to the asset’s carrying amount to determine if recording an impairment of such asset is necessary. If an impairment is indicated, we record an impairment loss equal to the difference between the carrying value and the fair value of the long-lived asset. This requires us to make long-term forecasts of the future revenues and the costs related to the assets subject to review. Forecasts require assumptions about demand for our products and future market conditions. Estimating future cash flows requires significant judgment, and our projections may vary from cash flows eventually realized. Future events and unanticipated changes to assumptions could require a provision for impairment in a future period. The effect of any impairment would be reflected in operating income in the Consolidated Statements of Operations. In addition, we estimate the useful lives of our property, plant and equipment and periodically review these estimates to determine whether these lives are appropriate.

Income Taxes

We account for income taxes under the asset and liability method, based on the income tax laws and rates in the countries in which operations are conducted, and income is earned. This approach requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the carrying amounts and the tax basis of assets and liabilities. Developing our provision for income taxes requires significant judgment and expertise in federal, international and state income tax laws, regulations and strategies, including the determination of deferred tax assets and liabilities and, if necessary, any valuation allowances that may be required for deferred tax assets. In assessing the extent to which net deferred tax assets may be realized, we consider whether it is more likely than not that some portion or all of the net deferred tax assets may not be realized. The ultimate realization of net deferred tax assets is dependent on the generation of future taxable income during the periods in which those temporary differences become deductible. Estimates may change as new events occur, estimates of future taxable income during the carryforward period are reduced or increased, additional information becomes available or operating environments change, which may result in a full or partial reversal of the valuation allowance. We will continue to assess the adequacy of the valuation allowance on a quarterly basis. Our judgments and tax strategies are subject to audit by various taxing authorities.

The objectives of accounting for income taxes are to recognize the amount of taxes payable or refundable for the current year and deferred tax liabilities and assets for the future tax consequences of events that have been recognized in an entity’s financial statements or tax returns. We recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such a position should be measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. Accounting literature also provides guidance on derecognition of income tax assets and liabilities, classification of current and deferred income tax assets and liabilities, accounting for interest and penalties associated with tax positions, and income tax disclosures. Judgment is required in assessing the future tax consequences of events that have been recognized in our financial statements or tax returns. Variations in the actual outcome of these future tax consequences could materially impact our financial statements.

Revenue Recognition

Our revenues are primarily generated from the manufacturing of custom-engineered products and systems under long-term, fixed-price contracts that may last from one month to several years, depending on the contract. Revenue from these contracts is generally recognized over time utilizing the cost-to-cost method. Under the cost-to-cost method, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance

obligation. We believe that this method is the most accurate representation of our performance because it directly measures the value of the services transferred to the customer over time as we incur costs on our contracts. Contract costs include all direct materials, labor and indirect costs related to contract performance, which may include indirect labor, supplies, tools, repairs and depreciation costs.

Warranty Costs

Estimated costs of warranties are accrued based on historical warranty claim costs in relation to current revenues. In addition, specific provisions are made when product failures are projected outside historical experience. Our standard terms and conditions of sale include a warranty for parts and service for one year. Occasionally, we provide service-type warranties that will extend the warranty period. Actual results could differ from our estimate.

Projects may require, on occasion, warranty terms that are longer than our standard terms due to the nature of the project. Extended warranty terms may be negotiated and included in our contracts. The allocated revenue associated with the extended warranty is deferred and recorded as a contract liability and recognized as revenue over the extended warranty period.

Research and Development Expense

Research and development activities are directed toward the development of new products and processes as well as improvements in existing products and processes. These costs, which primarily include salaries, contract services and supplies, are expensed as incurred. Such amounts were $6.2 million, $7.0 million and $6.7 million in Fiscal 2023, 2022 and 2021, respectively.

Foreign Currency Translation

The functional currency for our foreign subsidiaries is the local currency in which the entity is located. The financial statements of all subsidiaries with a functional currency other than the U.S. Dollar have been translated into U.S. Dollars. All assets and liabilities of foreign operations are translated into U.S. Dollars using period-end exchange rates, and all revenues and expenses are translated at average rates during the respective period. The U.S. Dollar results that arise from such translation, as well as exchange gains and losses on intercompany balances of a long-term investment nature, are included in the cumulative currency translation adjustments in accumulated other comprehensive loss in stockholders’ equity.

Stock-Based Compensation

We measure stock-based compensation cost at the grant date based on the fair value of the award. Compensation expense is recognized over the period during which the recipient is required to provide service in exchange for the awards, typically the vesting period. Excess income tax benefits related to stock-based compensation expense are recognized as income tax expense or benefit in the Consolidated Statements of Operations. Cash paid when directly withholding shares on an employee's behalf for tax withholding purposes is classified as a financing activity. We account for forfeitures as they occur, rather than estimate expected forfeitures.

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 1,377	$ 1,409	$ 1,252
Increases related to tax positions taken during the current period	400	240	251
Increases related to tax positions taken during a prior period	112	92	75
Decreases related to expiration of statute of limitations	0	(327)	0
Decreases related to settlement with taxing authorities	0	(37)	(169)
Balance at end of period	$ 1,889	$ 1,377	$ 1,409

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 54,525	$ 13,737	$ 631
Foreign currency translation adjustments	1,915	(8,689)	4,253
Gain (loss) on cash flow commodity hedge	325	(325)	0
Postretirement benefit adjustment, net of tax	(151)	372	(96)
Comprehensive income	$ 56,614	$ 5,095	$ 4,788

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481687/323-10-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 28
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-28

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482765/220-10-50-6

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-8

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-9

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 13: http://www.xbrl.org/2003/role/exampleRef
-Topic 946
-SubTopic 830
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480167/946-830-55-10

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483581/946-220-45-7

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(18))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(9))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-1

Reference 18: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 3
-Subparagraph (SX 210.6-09(1)(d))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483575/946-220-S99-3

Reference 19: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 20: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(ii))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 21: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 22: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 23: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1A
-Subparagraph (SX 210.13-01(a)(5))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1A

Reference 24: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(i))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 25: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(A))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 26: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iii)(B))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 27: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(4)(iv))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 28: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1B
-Subparagraph (SX 210.13-02(a)(5))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480097/470-10-S99-1B

Reference 29: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 30: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 31: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 32: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 33: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 34: http://www.xbrl.org/2003/role/disclosureRef
-Topic 205
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483499/205-20-50-7

Reference 35: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482740/230-10-45-28

Reference 36: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1A

Reference 37: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-1B

Reference 38: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(20))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 39: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(22))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

Quarterly Information

12 Months Ended

Sep. 30, 2023

Quarterly Financial Information Disclosure [Abstract]

Quarterly Information

The table below sets forth the unaudited consolidated operating results by fiscal quarter for the years ended September 30, 2023 and 2022 (in thousands, except per share data):


	2023 Quarters
	First(1)		Second(2)		Third(3)		Fourth(4)		2023
Revenues	$	126,858	$	171,444	$	192,365	$	208,641	$	699,308
Gross profit	19,464		33,437		42,670		51,982		147,553
Net income (loss)	1,162		8,473		18,454		26,436		54,525
Earnings (loss) per share:
Basic	$	0.10	$	0.71	$	1.55	$	2.22	$	4.59
Diluted	$	0.10	$	0.70	$	1.52	$	2.17	$	4.50

(1) The results for the first quarter of Fiscal 2023 demonstrated normal seasonality and were negatively impacted by holidays and work schedules compared to other quarterly periods.
(2) The results for the second quarter of Fiscal 2023 were positively impacted by a project cancellation of $1.6 million.
(3) The results for the third quarter of Fiscal 2023 were positively impacted by a project cancellation of $1.7 million.
(4) The results for the fourth quarter of Fiscal 2023 were positively impacted by project cancellations of $1.0 million and the reversal of a $1.9 million valuation allowance against the U.K. net deferred tax assets.


	2022 Quarters
	First(1)		Second		Third(2)		Fourth(3)		2022
Revenues	$	106,569	$	127,854	$	135,483	$	162,676	$	532,582
Gross profit	13,436		19,083		19,059		33,440		85,018
Net income (loss)	(2,846)		(1,217)		9,061		8,739		13,737
Earnings (loss) per share:
Basic	$	(0.24)	$	(0.10)	$	0.77	$	0.74	$	1.16
Diluted	$	(0.24)	$	(0.10)	$	0.76	$	0.73	$	1.15

(1) The results for the first quarter of Fiscal 2022 demonstrated normal seasonality and were negatively impacted by holidays and work schedules compared to other quarterly periods.
(2) The results for the third quarter of Fiscal 2022 were positively impacted by the release of a $5.9 million Canadian valuation allowance and a $2.0 million pre-tax gain on the sale of a non-core business within our Canadian operations.
(3) The results for the fourth quarter of Fiscal 2022 were positively impacted by a $2.5 million settlement of a claim for cost overruns from prior years related to a U.S. based municipal transit project.

The sum of the individual earnings per share amounts may not agree with year-to-date earnings per share as each period’s computation is based on the weighted-average number of shares outstanding during the period.

Detail of Selected Balance Sheet Accounts - Activity in Warranty Accrual (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]
Balance at beginning of period	$ 2,345	$ 2,531
Increase to warranty expense	3,752	1,425
Deduction for warranty charges	(2,800)	(1,564)
Change due to foreign currency translation	8	(47)
Balance at end of period	$ 3,305	$ 2,345

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (PARENTHETICAL) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Statement of Stockholders' Equity [Abstract]
Postretirement benefit adjustment, tax	$ 40	$ 99	$ 26

Fair Value Measurements (Tables)

12 Months Ended

Sep. 30, 2023

Fair Value Disclosures [Abstract]

Fair Value of Assets and Liabilities Measured on Recurring Basis

The following table summarizes the fair value of our assets and liabilities that were accounted for at fair value on a recurring basis as of September 30, 2023 (in thousands):


	Fair Value Measurements at September 30, 2023
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value at September 30, 2023
Assets:
Cash and cash equivalents	$	245,875	$	—	$	—	$	245,875
Short-term investments	33,134		—		—		33,134

Other assets	—		9,117		—		9,117
Liabilities:
Deferred compensation	—		9,145		—		9,145

The following table summarizes the fair value of our assets and liabilities that were accounted for at fair value on a recurring basis as of September 30, 2022 (in thousands):


	Fair Value Measurements at September 30, 2022
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value at September 30, 2022
Assets:
Cash and cash equivalents	$	101,954	$	—	$	—	$	101,954
Short-term investments	14,554		—		—		14,554

Other assets	—		7,730		—		7,730
Liabilities:
Deferred compensation	—		7,714		—		7,714

Summary of Significant Accounting Policies - Supplemental Disclosures of Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Cash paid (received) during the period for:
Interest received, net of interest expense	$ (5,465)	$ (334)	$ (73)
Income taxes paid, net of refunds	17,232	533	1,886
Non-cash capital expenditures	$ 183	$ 1,133	$ 226

Long-Term Debt	12 Months Ended
Long-Term Debt	Sep. 30, 2023
Debt Disclosure [Abstract]
Long-Term Debt	Long-Term Debt U.S. Revolver On March 31, 2023, we entered into a second amendment (the Second Amendment) to our credit agreement with Bank of America, N.A. (as amended, the U.S. Revolver). The Second Amendment increased the revolving credit facility, which is available for both borrowings and letters of credit, from $75.0 million to $125.0 million. As amended by the Second Amendment, the U.S. Revolver states that the lesser of $50 million or 50% of available cash may be deducted from the amount of letters of credit outstanding (not to be less than zero) when calculating the consolidated funded indebtedness, which is a component of the consolidated net leverage ratio. We have the option to cash collateralize all or a portion of the letters of credit outstanding, which would favorably impact the consolidated funded indebtedness calculation and the consolidated net leverage ratio. As of September 30, 2023, there were no amounts borrowed under the U.S. Revolver, and letters of credit outstanding were $89.1 million. There was $35.9 million available for the issuance of letters of credit and borrowings under the U.S. Revolver as of September 30, 2023. As of September 30, 2023, we are required to maintain certain financial covenants, the most significant of which are a consolidated net leverage ratio less than 3.0 to 1.0 and a consolidated interest coverage ratio of greater than 3.0 to 1.0. Our most restrictive covenant, the consolidated net leverage ratio, is the ratio of earnings before interest, taxes, depreciation, amortization and stock-based compensation (EBITDAS) to funded indebtedness. An increase in indebtedness, which includes letters of credit, or a decrease in EBITDAS could restrict our ability to issue letters of credit or borrow under the U.S. Revolver. Additionally, we must maintain a consolidated cash balance of $50 million at all times, which can be deducted from the letters of credit outstanding as noted above. The U.S. Revolver also contains a "material adverse effect" clause which is a material change in our operations, business, properties, liabilities or condition (financial or otherwise) or a material impairment of our ability to perform our obligations under the U.S. Revolver. As of September 30, 2023, we were in compliance with all of the financial covenants of the U.S. Revolver. The U.S. Revolver allows the Company to elect that any borrowing under the facility bears an interest rate based on either the base rate or the eurocurrency rate, in each case, plus the applicable rate. The base rate is generally the highest of (a) the federal funds rate plus 0.50%, (b) the Bank of America prime rate or (c) the Bloomberg Short-Term Bank Yield Index (BSBY) rate plus 1.00%. The applicable rate is generally a range from 0% to 2% depending on the type of loan and the Company's consolidated net leverage ratio. The U.S. Revolver is collateralized by a pledge of 100% of the voting capital stock of each of our domestic subsidiaries and 65% of the voting capital stock of each non-domestic subsidiary. The U.S. Revolver provides for customary events of default and carries cross-default provisions with other existing debt agreements. If an event of default (as defined in the U.S. Revolver) occurs and is continuing, on the terms and subject to the conditions set forth in the U.S. Revolver, amounts and letters of credit outstanding under the U.S. Revolver may be accelerated and may become immediately due and payable. On October 4, 2023, we entered into a third amendment to the U.S. Revolver (the Third Amendment) with Bank of America, N.A. and Texas Capital Bank has agreed to join as an additional lender under the U.S. Revolver. The Third Amendment increased the amount of the revolving line of credit from $125.0 million to $150.0 million and extended the expiry date to October 4, 2028. The aggregate commitment of $150.0 million consists of $100.0 million committed by Bank of America and $50.0 million committed by Texas Capital Bank. As amended by the Third Amendment, the lesser of $60.0 million or 60% of readily and available cash may be deducted from the amount of letters of credit outstanding (not to be less than zero) when calculating the consolidated funded indebtedness, which is a component of the consolidated net leverage ratio. We are now required to maintain a consolidated cash balance of $60.0 million at all times, which can be deducted from the letters of credit outstanding as stated above. Industrial Development Revenue Bonds We borrowed $8.0 million in October 2001 through a loan agreement funded with proceeds from tax-exempt industrial development revenue bonds (Bonds) for the completion of our Northlake, Illinois facility. The Bonds matured on October 1, 2021, and our final payment of $0.4 million was made upon maturity.

Quarterly Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 208,641	$ 192,365	$ 171,444	$ 126,858	$ 162,676	$ 135,483	$ 127,854	$ 106,569	$ 699,308	$ 532,582
Gross profit	51,982	42,670	33,437	19,464	33,440	19,059	19,083	13,436	147,553	85,018	$ 75,063
Net income (loss)	$ 26,436	$ 18,454	$ 8,473	$ 1,162	$ 8,739	$ 9,061	$ (1,217)	$ (2,846)	$ 54,525	$ 13,737	$ 631
Earnings (loss) per share
Basic (in dollars per share)	$ 2.22	$ 1.55	$ 0.71	$ 0.10	$ 0.74	$ 0.77	$ (0.10)	$ (0.24)	$ 4.59	$ 1.16	$ 0.05
Diluted (in dollars per share)	$ 2.17	$ 1.52	$ 0.70	$ 0.10	$ 0.73	$ 0.76	$ (0.10)	$ (0.24)	$ 4.50	$ 1.15	$ 0.05
Change in contract estimates due to project cancellations	$ 1,000	$ 1,700	$ 1,600						$ 700
Decrease in valuation allowance	$ (1,900)					$ 5,900			(1,800)
Gain on sale of non-core business						$ 2,000			0	$ 2,006	$ 0
Revenue recognized related to settlement of a claim for cost overruns from prior years					$ 2,500				$ 70,500

Goodwill and Intangible Assets - Narrative (Details) - USD ($)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 1,000,000
Impairment of goodwill	0	$ 0	$ 0
Amortization of intangible assets	$ 0	$ 0	$ 157,000

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References + Details

Detail of Selected Balance Sheet Accounts - Narrative (Details) - USD ($)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	$ 243,312,000	$ 235,327,000
Depreciation	8,600,000	9,400,000	$ 10,200,000
Assets under finance leases
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	$ 0	$ 0

Segment Information - Schedule of Revenues from External Customers by Geographical Areas (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2023 USD ($) segment	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Reportable segments \| segment	1
Revenues	$ 699,308	$ 532,582	$ 470,559
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	557,934	404,973	351,422
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	84,090	81,218	68,655
Middle East and Africa
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	14,998	20,712	26,615
Asia/Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	6,188	4,885	8,889
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	26,699	17,699	13,027
Mexico, Central and South America
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 9,399	$ 3,095	$ 1,951

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 924
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479941/924-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-5

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 30
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-30

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-42

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-40

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-41

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 606
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479806/606-10-50-4

+ Details

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Sep. 30, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Statement [Abstract]
Revenues	$ 699,308	$ 532,582	$ 470,559
Cost of goods sold	551,755	447,564	395,496
Gross profit	147,553	85,018	75,063
Selling, general and administrative expenses	78,813	70,831	67,217
Research and development expenses	6,220	6,963	6,670
Amortization of intangible assets	0	0	157
Operating income	62,520	7,224	1,019
Other income	0	(2,285)	0
Interest income, net	(6,430)	(334)	(73)
Income before income taxes	68,950	9,843	1,092
Income tax provision (benefit)	14,425	(3,894)	461
Net income	$ 54,525	$ 13,737	$ 631
Earnings per share:
Basic (in dollars per share)	$ 4.59	$ 1.16	$ 0.05
Diluted (in dollars per share)	$ 4.50	$ 1.15	$ 0.05
Weighted average shares:
Basic (in shares)	11,879	11,797	11,705
Diluted (in shares)	12,120	11,943	11,789
Dividends per share (in dollars per share)	$ 1.05	$ 1.04	$ 1.04

Revenue - Performance Obligations (Details) $ in Millions	12 Months Ended
Revenue - Performance Obligations (Details) $ in Millions	Sep. 30, 2023 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Standard assurance warranty period	1 year
Revenue, remaining performance obligation, amount	$ 1,300.0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation, amount	$ 648.0
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months

Audit Information	12 Months Ended
Audit Information	Sep. 30, 2023
Audit Information [Abstract]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Houston, Texas
Auditor Firm ID	238

Income Taxes (Tables)

12 Months Ended

Sep. 30, 2023

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Provision (Benefit)

The components of the income tax provision were as follows (in thousands):


	Year Ended September 30,
	2023		2022		2021
Current:
Federal	$	18,129	$	557	$	911
State	4,036		403		472
Foreign	107		7		73
	22,272		967		1,456
Deferred:
Federal	(7,458)		(154)		(1,062)
State	(1,499)		(41)		(30)
Foreign	1,110		(4,666)		97
	(7,847)		(4,861)		(995)
Total income tax provision (benefit)	$	14,425	$	(3,894)	$	461

Schedule of Income Before Income Taxes

Income before income taxes was as follows (in thousands):


	Year Ended September 30,
	2023		2022		2021
U.S.	$	56,923	$	3,175	$	3,076
Foreign	12,027		6,668		(1,984)
Income before income taxes	$	68,950	$	9,843	$	1,092

Schedule of Effective Income Tax Rate Reconciliation

A reconciliation of the statutory U.S. income tax rate and the effective income tax rate, as computed on earnings before income tax provision (benefit) in each of the three years presented in the Consolidated Statements of Operations, was as follows:


	Year Ended September 30,
	2023		2022		2021
Statutory rate	21	%	21	%	21	%
State income taxes, net of federal benefit	3		3		25
Research and development credit	(2)		(14)		(101)
Foreign rate differential	—		1		10
Foreign taxes	—		—		10
Valuation allowance	(3)		(62)		62

Deferred tax rate differential	—		(1)		(19)
Non-deductible expenses	1		9		30
Impact of U.S. global intangible taxes and benefits	1		3		—
Other	—		—		4
Effective rate	21	%	(40)	%	42	%

Schedule of Deferred Tax Assets and Liabilities

The net deferred income tax asset was comprised of the following (in thousands):


	September 30,
	2023		2022





Gross assets	$	20,522	$	17,941
Gross liabilities and valuation allowance	(3,458)		(8,780)
Net deferred income tax asset	$	17,064	$	9,161

The tax effect of temporary differences between U.S. GAAP accounting and federal income tax accounting creating deferred income tax assets and liabilities was as follows (in thousands):


	September 30,
	2023		2022
Deferred Tax Assets:
Net operating loss	$	7,432	$	10,186
Depreciation and amortization	4,573		—
Deferred compensation	2,274		1,897
Stock-based compensation	1,555		1,083
Credit carryforwards	1,378		1,332
Uniform capitalization and inventory	1,253		1,506
Reserve for accrued employee benefits	988		872
Warranty accrual	752		559




Other(1)	317		506
Deferred tax assets	$	20,522	$	17,941
Deferred Tax Liabilities:
Depreciation and amortization	$	—	$	(3,764)
Retention and other	(1,491)		(1,229)
Deferred tax liabilities	$	(1,491)	$	(4,993)
Less: valuation allowance	(1,967)		(3,787)
Net deferred tax asset	$	17,064	$	9,161

(1) Certain prior year amounts have been reclassified for consistency with the current year presentation.

Reconciliation of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of the unrecognized tax benefits follows (in thousands):


	Year Ended September 30,
	2023		2022		2021
Balance at beginning of period	$	1,377	$	1,409	$	1,252
Increases related to tax positions taken during the current period	400		240		251
Increases related to tax positions taken during a prior period	112		92		75
Decreases related to expiration of statute of limitations	—		(327)		—
Decreases related to settlement with taxing authorities	—		(37)		(169)
Balance at end of period	$	1,889	$	1,377	$	1,409

Long-Term Debt - Narrative (Details)	12 Months Ended
Long-Term Debt - Narrative (Details)	Sep. 30, 2023 USD ($)	Oct. 04, 2023 USD ($)	Oct. 03, 2023 USD ($)	Mar. 31, 2023 USD ($)	Mar. 30, 2023 USD ($)	Oct. 01, 2021 USD ($)	Oct. 31, 2001 USD ($)
Industrial Development Revenue Bonds
Line of Credit Facility [Line Items]
Borrowings							$ 8,000,000
Final annual redemption						$ 400,000
Amended And Restated Credit Agreement \| U.S. Revolver
Line of Credit Facility [Line Items]
Revolving credit facility					$ 75,000,000
Percentage of voting capital stock pledged as collateral	100.00%
Non-domestic subsidiaries of voting capital stock	65.00%
Credit Agreement Second Amendment \| U.S. Revolver
Line of Credit Facility [Line Items]
Revolving credit facility				$ 125,000,000
Readily available cash deductible from letters of credit outstanding (lesser of)				$ 50,000,000
Readily available cash percentage deductible from letters of credit (lesser of)				50.00%
Letters of credit, collateral outstanding (not to be less than)				$ 0
Revolving credit facility borrowings, outstanding amount	$ 0
Amount of credit facility remaining borrowing capacity	$ 35,900,000
Debt covenant, consolidated leverage ratio (less than)	3.0
Debt covenant, consolidated interest coverage ratio (greater than)	3.0
Cash collateral pledged balance	$ 50,000,000
Credit Agreement Second Amendment \| U.S. Revolver \| Subsequent Event
Line of Credit Facility [Line Items]
Revolving credit facility			$ 125,000,000
Credit Agreement Second Amendment \| U.S. Revolver \| Federal Funds Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.50%
Credit Agreement Second Amendment \| U.S. Revolver \| Bloomberg Short-Term Bank Yield Index
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.00%
Credit Agreement Second Amendment \| U.S. Revolver \| Base Rate \| Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.00%
Credit Agreement Second Amendment \| U.S. Revolver \| Base Rate \| Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate	2.00%
Credit Agreement Second Amendment \| U.S. Revolver \| Financial Standby Letter of Credit
Line of Credit Facility [Line Items]
Guarantee liability, letters of credit	$ 89,100,000
Credit Agreement Third Amendment \| U.S. Revolver \| Subsequent Event
Line of Credit Facility [Line Items]
Revolving credit facility		$ 150,000,000
Readily available cash deductible from letters of credit outstanding (lesser of)		$ 60,000,000
Readily available cash percentage deductible from letters of credit (lesser of)		60.00%
Letters of credit, collateral outstanding (not to be less than)		$ 0
Cash collateral pledged balance		60,000,000
Credit Agreement Third Amendment \| U.S. Revolver \| Bank of America \| Subsequent Event
Line of Credit Facility [Line Items]
Revolving credit facility		100,000,000
Credit Agreement Third Amendment \| U.S. Revolver \| Texas Capital Bank \| Subsequent Event
Line of Credit Facility [Line Items]
Revolving credit facility		$ 50,000,000

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Statutory rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefit	3.00%	3.00%	25.00%
Research and development credit	(2.00%)	(14.00%)	(101.00%)
Foreign rate differential	0.00%	1.00%	10.00%
Foreign taxes	0.00%	0.00%	10.00%
Valuation allowance	(3.00%)	(62.00%)	62.00%
Deferred tax rate differential	0.00%	(1.00%)	(19.00%)
Non-deductible expenses	1.00%	9.00%	30.00%
Impact of U.S. global intangible taxes and benefits	1.00%	3.00%	0.00%
Other	0.00%	0.00%	4.00%
Effective rate	21.00%	(40.00%)	42.00%

Stock-Based Compensation - Schedule of Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs)	12 Months Ended
	Sep. 30, 2023 $ / shares shares
Number of Restricted Stock Units
Outstanding Beginning Balance (in shares) \| shares	239,862
Granted (in shares) \| shares	147,100
Vested (in shares) \| shares	(79,004)
Forfeited (in shares) \| shares	(15,461)
Outstanding Ending Balance (in shares) \| shares	292,497
Weighted Average Grant Value Per Share
Outstanding Beginning Balance (in dollars per share) \| $ / shares	$ 26.11
Granted (in dollars per share) \| $ / shares	21.26
Vested (in dollars per share) \| $ / shares	29.24
Forfeited (in dollars per share) \| $ / shares	37.91
Outstanding Ending Balance (in dollars per share) \| $ / shares	$ 22.90

Subsequent Event (Details) - $ / shares		12 Months Ended
Subsequent Event (Details) - $ / shares	Oct. 31, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Subsequent Event [Line Items]
Cash dividends declared (in dollars per share)		$ 1.05	$ 1.04	$ 1.04
Subsequent Event
Subsequent Event [Line Items]
Cash dividends declared (in dollars per share)	$ 0.2625

Revenue - Revenue Recognition (Details) - Product Concentration Risk	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Revenue from Contract with Customer, Product and Service Benchmark \| Transferred over Time
Revenue from External Customer [Line Items]
Revenue from sales orders, percentage	94.00%	94.00%
Revenue from Contract with Customer Benchmark \| Transferred at Point in Time
Revenue from External Customer [Line Items]
Revenue from sales orders, percentage	6.00%	6.00%

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Operating Activities:
Net income	$ 54,525	$ 13,737	$ 631
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	8,606	9,358	10,335
Gain on sale of division	0	(2,006)	0
Stock-based compensation	4,599	4,090	2,583
Bad debt expense, net	(54)	162	48
Deferred income taxes	(7,847)	(4,861)	(995)
Changes in operating assets and liabilities:
Accounts receivable, net	(99,718)	(31,629)	(7,509)
Contract assets and liabilities, net	227,598	3,122	(39,951)
Inventories	(13,276)	(21,426)	(599)
Income taxes	4,812	688	(473)
Prepaid expenses and other current assets	(3,253)	(2,577)	412
Accounts payable	(6,167)	18,594	9,760
Accrued liabilities	11,729	8,908	(3,151)
Other, net	999	258	(1,552)
Net cash provided by (used in) operating activities	182,553	(3,582)	(30,461)
Investing Activities:
Purchases of short-term investments	(33,515)	(22,381)	(27,735)
Maturities of short-term investments	14,748	26,320	27,688
Proceeds from sale of division	0	4,348	0
Purchases of property, plant and equipment	(7,819)	(2,451)	(2,931)
Proceeds from sale of property, plant and equipment	12	629	40
Proceeds from life insurance policy	0	0	474
Net cash provided by (used in) investing activities	(26,574)	6,465	(2,464)
Financing Activities:
Payments on industrial development revenue bonds	0	(400)	(400)
Shares withheld in lieu of employee tax withholding	(652)	(675)	(632)
Dividends paid	(12,407)	(12,233)	(12,142)
Net cash used in financing activities	(13,059)	(13,308)	(13,174)
Net increase (decrease) in cash, cash equivalents and restricted cash	142,920	(10,425)	(46,099)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	1,001	(1,935)	197
Cash, cash equivalents and restricted cash at beginning of period	101,954	114,314	160,216
Cash, cash equivalents and restricted cash at end of period	$ 245,875	$ 101,954	$ 114,314

Divestiture (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
Divestiture (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Jun. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of division			$ 0	$ 4,348	$ 0
Gain on sale		$ 2,000	0	$ 2,006	$ 0
Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of division	$ 4,300
Gain on sale			$ 2,000

Revenue - Contract Estimates (Details) $ in Millions	12 Months Ended
Revenue - Contract Estimates (Details) $ in Millions	Sep. 30, 2023 USD ($) project	Sep. 30, 2022 USD ($)
Revenue from Contract with Customer [Abstract]
Change in contract estimates related to projects in progress	$ 13.6	$ 11.3
Projects cancelled \| project	4
Change in contract estimates due to project cancellations	$ 4.3

Earnings Per Share

12 Months Ended

Sep. 30, 2023

Earnings Per Share [Abstract]

Earnings Per Share

We compute basic earnings per share by dividing net income by the weighted average number of common shares outstanding during the period. Diluted earnings per common and potential common share include the weighted average of additional shares associated with the incremental effect of dilutive restricted stock and restricted stock units.

The following table reconciles basic and diluted weighted average shares used in the computation of earnings per share (in thousands, except per share data):


	Year Ended September 30,
	2023		2022		2021
Numerator:
Net income	$	54,525	$	13,737	$	631
Denominator:
Weighted average basic shares	11,879		11,797		11,705
Dilutive effect of restricted stock units	241		146		84
Weighted average diluted shares	12,120		11,943		11,789

Earnings per share:
Basic	$	4.59	$	1.16	$	0.05
Diluted	$	4.50	$	1.15	$	0.05

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Sep. 30, 2023

Accounting Policies [Abstract]

Supplemental Disclosures of Cash Flow Information

Supplemental Disclosures of Cash Flow Information (in thousands):


	Year Ended September 30,
	2023		2022		2021
Cash paid (received) during the period for:
Interest received, net of interest expense	$	(5,465)	$	(334)	$	(73)
Income taxes paid, net of refunds	17,232		533		1,886
Non-cash capital expenditures	183		1,133		226

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Numerator:
Net income	$ 26,436	$ 18,454	$ 8,473	$ 1,162	$ 8,739	$ 9,061	$ (1,217)	$ (2,846)	$ 54,525	$ 13,737	$ 631
Denominator:
Weighted average basic shares (in shares)									11,879	11,797	11,705
Dilutive effect of restricted stock units (in shares)									241	146	84
Weighted average diluted shares (in shares)									12,120	11,943	11,789
Earnings per share:
Basic (in dollars per share)	$ 2.22	$ 1.55	$ 0.71	$ 0.10	$ 0.74	$ 0.77	$ (0.10)	$ (0.24)	$ 4.59	$ 1.16	$ 0.05
Diluted (in dollars per share)	$ 2.17	$ 1.52	$ 0.70	$ 0.10	$ 0.73	$ 0.76	$ (0.10)	$ (0.24)	$ 4.50	$ 1.15	$ 0.05

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-7

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482662/260-10-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-10

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(25))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(27))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

Reference 15: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(23))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 16: http://www.xbrl.org/2003/role/exampleRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 52
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-52

Reference 17: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-7

+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-3

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (e)(4)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 65
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480175/815-40-65-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-11

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-7

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-2

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 60B
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-60B

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 250
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483443/250-10-50-4

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482662/260-10-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03(25))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483621/220-10-S99-2

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(27))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(23))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483586/944-220-S99-1

Reference 15: http://www.xbrl.org/2003/role/exampleRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 52
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482635/260-10-55-52

Reference 16: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482689/260-10-45-7

+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

Income Taxes

12 Months Ended

Sep. 30, 2023

Income Tax Disclosure [Abstract]

Income Taxes

The components of the income tax provision were as follows (in thousands):


	Year Ended September 30,
	2023		2022		2021
Current:
Federal	$	18,129	$	557	$	911
State	4,036		403		472
Foreign	107		7		73
	22,272		967		1,456
Deferred:
Federal	(7,458)		(154)		(1,062)
State	(1,499)		(41)		(30)
Foreign	1,110		(4,666)		97
	(7,847)		(4,861)		(995)
Total income tax provision (benefit)	$	14,425	$	(3,894)	$	461

Income before income taxes was as follows (in thousands):


	Year Ended September 30,
	2023		2022		2021
U.S.	$	56,923	$	3,175	$	3,076
Foreign	12,027		6,668		(1,984)
Income before income taxes	$	68,950	$	9,843	$	1,092


	Year Ended September 30,
	2023		2022		2021
Statutory rate	21	%	21	%	21	%
State income taxes, net of federal benefit	3		3		25
Research and development credit	(2)		(14)		(101)
Foreign rate differential	—		1		10
Foreign taxes	—		—		10
Valuation allowance	(3)		(62)		62

Deferred tax rate differential	—		(1)		(19)
Non-deductible expenses	1		9		30
Impact of U.S. global intangible taxes and benefits	1		3		—
Other	—		—		4
Effective rate	21	%	(40)	%	42	%

Our income tax provision reflects an effective tax rate on pre-tax results of 21% in Fiscal 2023 compared to negative 40% and 42% in Fiscal 2022 and 2021, respectively. The income tax provision for Fiscal 2023 was favorably impacted by the reversal of a valuation allowance on the United Kingdom (U.K.) deferred tax assets that were previously fully reserved, in addition to the current year estimated Research and Development Tax Credit (R&D Tax Credit). These items were offset by state tax expense, the tax expense related to certain nondeductible expenses and an inclusion related to U.S. global intangible income.

The income tax benefit for Fiscal 2022 was largely a result of the reversal of a valuation allowance on the Canadian deferred tax assets that were previously fully reserved, in addition to the estimated R&D Tax Credit. These items were partially offset by the tax expense related to certain nondeductible expenses, the gain on the disposition of a small, non-core division of our Canadian operations and an inclusion related to U.S. global intangible income.

The income tax provision for Fiscal 2021 was favorably impacted by the estimated R&D Tax Credit as well as the utilization of net operating loss carryforwards in Canada that were fully reserved with a valuation allowance. In Fiscal 2021, the tax provision was negatively impacted by the losses recognized in other foreign jurisdictions, primarily in the U.K., that were reserved with a valuation allowance as well as the establishment of a valuation allowance against the deferred tax assets in Mexico.

We record and maintain valuation allowances against the deferred tax assets of various foreign jurisdictions until sufficient evidence is available to demonstrate that it is more likely than not that the net deferred tax assets will be recognized. As of each reporting date, management considers new evidence, both positive and negative, that could affect its view of the future realization of deferred tax assets. During the period ended September 30, 2023, management determined that there was sufficient positive evidence to conclude that the U.K. net deferred tax assets of $1.9 million were realizable. This determination was based on operating results over the past three years and anticipated future taxable income from our U.K. operations. The valuation allowance was released accordingly, and a $1.9 million tax benefit and corresponding increase in the deferred tax assets were recorded. Likewise, during the period ended June 30, 2022, management concluded that Canadian net deferred tax assets of $5.9 million were realizable based on current and anticipated market conditions, continued market diversification, operating results over the past three years and anticipated future taxable income from our Canadian operations. The release of the Canadian valuation allowance resulted in a $5.9 million tax benefit and a corresponding increase in the deferred tax assets. During our assessment of deferred income taxes in Fiscal 2021, we recorded a valuation allowance of $0.1 million against our Mexican net deferred tax assets. In assessing the realizability of net deferred tax assets, we determined it was more likely than not that the net deferred tax assets may not be realized based upon recent Mexican tax losses and anticipated results in the near term. Estimates may change as new events occur, estimates of future taxable income are reduced or increased, additional information becomes available, or operating environments change, which may result in a full or partial reversal of the valuation allowance.

We have not recorded deferred income taxes on $17.9 million of undistributed earnings of our foreign subsidiaries because of management’s intent to indefinitely reinvest such earnings. Upon distribution of these earnings in the form of dividends or otherwise, we may be subject to U.S. income taxes and foreign withholding taxes. It is not practical, however, to estimate the amount of taxes that may be payable on the eventual remittance of these earnings.

We are subject to income tax in the U.S., multiple state jurisdictions and certain international jurisdictions, primarily the U.K. and Canada. We do not consider any state in which we do business to be a major tax jurisdiction. The significant jurisdictions that remain open to examination are as follows: Canada 2016 – 2022, U.K. 2022 and the U.S. 2019 – 2022. As of September 30, 2023, we did not have any state audits underway that would have a material impact on our financial position or results of operations.

The net deferred income tax asset was comprised of the following (in thousands):


	September 30,
	2023		2022





Gross assets	$	20,522	$	17,941
Gross liabilities and valuation allowance	(3,458)		(8,780)
Net deferred income tax asset	$	17,064	$	9,161

The tax effect of temporary differences between U.S. GAAP accounting and federal income tax accounting creating deferred income tax assets and liabilities was as follows (in thousands):


	September 30,
	2023		2022
Deferred Tax Assets:
Net operating loss	$	7,432	$	10,186
Depreciation and amortization	4,573		—
Deferred compensation	2,274		1,897
Stock-based compensation	1,555		1,083
Credit carryforwards	1,378		1,332
Uniform capitalization and inventory	1,253		1,506
Reserve for accrued employee benefits	988		872
Warranty accrual	752		559




Other(1)	317		506
Deferred tax assets	$	20,522	$	17,941
Deferred Tax Liabilities:
Depreciation and amortization	$	—	$	(3,764)
Retention and other	(1,491)		(1,229)
Deferred tax liabilities	$	(1,491)	$	(4,993)
Less: valuation allowance	(1,967)		(3,787)
Net deferred tax asset	$	17,064	$	9,161

(1) Certain prior year amounts have been reclassified for consistency with the current year presentation.

We have deferred tax assets related to international net operating loss carryforwards of $6.8 million that are not reserved with a valuation allowance available to offset future tax liabilities in the respective jurisdictions. The majority of these net operating loss carryforwards are related to our Canadian operations and expire beginning in 2033. The remaining unreserved net operating loss carryforwards related to other jurisdictions have an indefinite carryforward period. As of September 30, 2023, the majority of our tax credit carryforwards are fully reserved with a valuation allowance.

The net decrease in the total valuation allowance during the year was $1.8 million, which was largely a result of the reversal of the U.K. valuation allowance. In assessing the realizability of net deferred tax assets, we consider whether it is more likely than not that some portion or all of the net deferred tax assets may not be realized. The ultimate realization of net deferred tax assets is dependent on the generation of future taxable income during the periods in which those temporary differences become deductible.

A reconciliation of the beginning and ending amount of the unrecognized tax benefits follows (in thousands):


	Year Ended September 30,
	2023		2022		2021
Balance at beginning of period	$	1,377	$	1,409	$	1,252
Increases related to tax positions taken during the current period	400		240		251
Increases related to tax positions taken during a prior period	112		92		75
Decreases related to expiration of statute of limitations	—		(327)		—
Decreases related to settlement with taxing authorities	—		(37)		(169)
Balance at end of period	$	1,889	$	1,377	$	1,409

Included in the balance of unrecognized tax benefits at the end of Fiscal 2023, 2022, and 2021 are $1.6 million, $1.1 million, and $1.1 million, respectively, of tax benefits that, if recognized, would affect the effective tax rate. Our policy is to recognize interest and penalties related to income tax matters as tax expense. The amount of interest and penalty expense recorded for the year ended September 30, 2023 was not material.

Management believes that, within the next twelve months, it is reasonably possible that the unrecognized tax benefits will decrease by approximately $0.6 million due to the expiration of certain federal statutes of limitations. We are unable to make

reasonably reliable estimates regarding the timing of future cash outflows, if any, associated with the remaining unrecognized tax benefits for the open periods of fiscal years ended September 30, 2019 – 2023.

Management believes that an adequate provision has been made for any adjustments that may result from tax examinations. However, the outcome of tax audits cannot be predicted with certainty. If any issues addressed in our tax audits are resolved in a manner not consistent with management’s expectations, we could be required to adjust our provision for income tax in the period such resolution occurs.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480990/946-20-50-13

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//740/tableOfContent

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-14

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-21

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 270
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482526/740-270-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 17
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-17

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479360/740-10-S99-2

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482603/740-30-50-2

+ Details

Earnings Per Share (Tables)

12 Months Ended

Sep. 30, 2023

Earnings Per Share [Abstract]

Computation of Basic and Diluted Earnings Per Share

The following table reconciles basic and diluted weighted average shares used in the computation of earnings per share (in thousands, except per share data):


	Year Ended September 30,
	2023		2022		2021
Numerator:
Net income	$	54,525	$	13,737	$	631
Denominator:
Weighted average basic shares	11,879		11,797		11,705
Dilutive effect of restricted stock units	241		146		84
Weighted average diluted shares	12,120		11,943		11,789

Earnings per share:
Basic	$	4.59	$	1.16	$	0.05
Diluted	$	4.50	$	1.15	$	0.05

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Pay vs Performance Disclosure
Net income (loss)	$ 26,436	$ 18,454	$ 8,473	$ 1,162	$ 8,739	$ 9,061	$ (1,217)	$ (2,846)	$ 54,525	$ 13,737	$ 631

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

+ Details

Revenue (Tables)

12 Months Ended

Sep. 30, 2023

Revenue from Contract with Customer [Abstract]

Contract Assets and Liabilities

Contract assets and liabilities as of September 30, 2023 and September 30, 2022 are summarized below (in thousands):


	September 30,
	2023		2022
Contract assets	$	60,621	$	88,351
Contract liabilities	(279,796)		(79,857)
Net contract asset (liability)	$	(219,175)	$	8,494

Disaggregation of Revenue

The following tables present our disaggregated revenue by geographic destination and market sector for the years ended September 30, 2023, 2022 and 2021 (in thousands):


	2023		2022		2021
United States	$	557,934	$	404,973	$	351,422
Canada	84,090		81,218		68,655
Middle East and Africa	14,998		20,712		26,615
Asia/Pacific	6,188		4,885		8,889
Europe	26,699		17,699		13,027
Mexico, Central and South America	9,399		3,095		1,951
Total revenues by geographic destination	$	699,308	$	532,582	$	470,559


	2023		2022		2021
Oil and gas (excludes petrochemical)	$	273,117	$	215,235	$	187,660
Petrochemical	94,188		66,538		58,986
Electric utility	158,400		122,361		111,244
Traction power	28,112		44,930		59,106
Commercial and other industrial	103,966		56,448		27,065
All others	41,525		27,070		26,498
Total revenues by market sector	$	699,308	$	532,582	$	470,559

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Current Assets:
Cash and cash equivalents	$ 245,875	$ 101,954
Short-term investments	33,134	14,554
Accounts receivable, less allowance for credit losses of $273 and $344	206,591	106,111
Contract assets	60,621	88,351
Inventories	63,865	50,415
Income taxes receivable	100	105
Prepaid expenses	5,419	4,679
Other current assets	6,380	3,814
Total Current Assets	621,985	369,983
Property, plant and equipment, net	97,625	98,628
Operating lease assets, net	1,436	2,179
Goodwill and intangible assets, net	1,003	1,003
Deferred income taxes	13,129	12,426
Other assets	17,064	9,161
Total Assets	752,242	493,380
Current Liabilities:
Accounts payable	56,666	63,423
Contract liabilities	279,796	79,857
Accrued compensation and benefits	29,947	24,785
Accrued product warranty	3,305	2,345
Current operating lease liabilities	773	1,777
Income taxes payable	6,517	1,720
Other current liabilities	18,682	12,466
Total Current Liabilities	395,686	186,373
Deferred compensation (Note J)	9,145	7,749
Long-term operating lease liabilities	663	545
Other long-term liabilities	1,722	1,507
Total Liabilities	407,216	196,174
Commitments and Contingencies (Note H)
Stockholders' Equity:
Preferred stock, par value $0.01; 5,000,000 shares authorized; none issued	0	0
Common stock, par value $0.01; 30,000,000 shares authorized; 12,668,001 and 12,588,011 shares issued, respectively	127	126
Additional paid-in capital	71,526	67,439
Retained earnings	325,281	283,638
Treasury stock, 806,018 shares at cost	(24,999)	(24,999)
Accumulated other comprehensive loss	(26,909)	(28,998)
Total Stockholders' Equity	345,026	297,206
Total Liabilities and Stockholders' Equity	$ 752,242	$ 493,380

Divestiture	12 Months Ended
Divestiture	Sep. 30, 2023
Discontinued Operations and Disposal Groups [Abstract]
Divestiture	Divestiture On June 30, 2022, we sold a non-core, industrial valve repair and servicing business within our Canadian operations and received proceeds of $4.3 million. We recorded a $2.0 million pre-tax gain on this transaction, which has been presented in other income on our Consolidated Statement of Operations for the year ended September 30, 2023.

Leases - Components of Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Leases [Abstract]
Operating lease cost	$ 1,457	$ 2,146	$ 2,435
Less: sublease income	(515)	(685)	(706)
Variable lease cost	369	457	443
Short-term lease cost	1,864	1,643	1,281
Total lease cost	$ 3,175	$ 3,561	$ 3,453

Stock-Based Compensation (Tables)

12 Months Ended

Sep. 30, 2023

Share-Based Payment Arrangement [Abstract]

Schedule of Restricted Stock Units Activity

Total RSU activity (number of shares) for the past fiscal year is summarized below:


	Number of Restricted Stock Units	Weighted Average Grant Value Per Share
Outstanding at September 30, 2022	239,862	$	26.11
Granted	147,100	21.26
Vested	(79,004)	29.24
Forfeited/cancelled	(15,461)	37.91
Outstanding at September 30, 2023	292,497	$	22.90

Fair Value Measurements

12 Months Ended

Sep. 30, 2023

Fair Value Disclosures [Abstract]

Fair Value Measurements

We measure certain financial assets and liabilities at fair value. Fair value is defined as an “exit price,” which represents the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants as of the measurement date. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in valuing an asset or liability. The accounting guidance requires the use of valuation techniques to measure fair value that maximize the use of observable inputs and minimize the use of unobservable inputs. As a basis for considering such assumptions and inputs, a fair value hierarchy has been established that identifies and prioritizes three levels of inputs to be used in measuring fair value.

The three levels of the fair value hierarchy are as follows:

Level 1 — Observable inputs such as quoted prices (unadjusted) in active markets for identical assets or liabilities.

Level 2 — Inputs other than the quoted prices in active markets that are observable either directly or indirectly, including quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active or other inputs that are observable or can be corroborated by observable market data.

Level 3 — Unobservable inputs that are supported by little or no market data and require the reporting entity to develop its own assumptions.

The following table summarizes the fair value of our assets and liabilities that were accounted for at fair value on a recurring basis as of September 30, 2023 (in thousands):


	Fair Value Measurements at September 30, 2023
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value at September 30, 2023
Assets:
Cash and cash equivalents	$	245,875	$	—	$	—	$	245,875
Short-term investments	33,134		—		—		33,134

Other assets	—		9,117		—		9,117
Liabilities:
Deferred compensation	—		9,145		—		9,145

The following table summarizes the fair value of our assets and liabilities that were accounted for at fair value on a recurring basis as of September 30, 2022 (in thousands):


	Fair Value Measurements at September 30, 2022
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Fair Value at September 30, 2022
Assets:
Cash and cash equivalents	$	101,954	$	—	$	—	$	101,954
Short-term investments	14,554		—		—		14,554

Other assets	—		7,730		—		7,730
Liabilities:
Deferred compensation	—		7,714		—		7,714

Fair value guidance requires certain fair value disclosures to be presented in both interim and annual reports. The estimated fair value amounts of financial instruments have been determined using available market information and valuation methodologies described below.

Cash and cash equivalents – Cash and cash equivalents, primarily funds held in money market savings instruments, are reported at their current carrying value, which approximates fair value due to the short-term nature of these instruments and are included in cash and cash equivalents in our Consolidated Balance Sheets.

Short-term Investments – Short-term investments include time deposits with original maturities of three months or more.

Other Assets and Deferred Compensation – We hold investments in the Rabbi Trust for our deferred compensation plan. The assets are primarily related to company-owned life insurance policies and are included in other assets in the accompanying Consolidated Balance Sheets. Because the mutual funds and company-owned life insurance policies are combined in the plan, they are therefore categorized as Level 2 in the fair value measurement hierarchy. The deferred compensation liability represents the investment options that the plan participants have designated to serve as the basis for measurement of the notional value of their accounts. Because the deferred compensation liability is intended to offset the plan assets, it is also categorized as Level 2 in the fair value measurement hierarchy.

There were no transfers between levels within the fair value measurement hierarchy during the year ended September 30, 2023.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Detail of Selected Balance Sheet Accounts - Components of Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Raw materials, parts and sub-assemblies	$ 68,631	$ 54,220
Work-in-progress	1,379	1,202
Provision for excess and obsolete inventories	(6,145)	(5,007)
Total inventories	$ 63,865	$ 50,415

Subsequent Event	12 Months Ended
Subsequent Event	Sep. 30, 2023
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event Quarterly Dividend Declared On October 31, 2023, our Board of Directors declared a quarterly cash dividend on our common stock in the amount of $0.2625 per share. The dividend is payable on December 13, 2023 to shareholders of record at the close of business on November 15, 2023.

Leases - Operating Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Assets:
Operating lease assets, net	$ 1,436	$ 2,179
Liabilities:
Current operating lease liabilities	773	1,777
Long-term operating lease liabilities	663	545
Total lease liabilities	$ 1,436	$ 2,322

Goodwill and Intangible Assets	12 Months Ended
Goodwill and Intangible Assets	Sep. 30, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Our intangible assets consist of goodwill of $1.0 million, which is not being amortized. In Fiscal 2021, our purchased technology was fully amortized, and we no longer have any intangible assets subject to amortization. No impairment expense has been recorded for the last three fiscal years. Amortization of intangible assets recorded for the year ended September 30, 2021 was $0.2 million.

Stock-Based Compensation

12 Months Ended

Sep. 30, 2023

Share-Based Payment Arrangement [Abstract]

Stock-Based Compensation

We have the following stock-based compensation plans:

Restricted Stock Units

In February 2014, our stockholders approved and adopted at the Annual Meeting of Stockholders the 2014 Equity Incentive Plan (the 2014 Plan), which replaced our 2006 Equity Compensation Plan (2006 Plan). Persons eligible to receive awards under the 2014 Plan include our officers and employees. The 2014 Plan authorizes stock options, stock appreciation rights, restricted stock, restricted stock units (RSUs) and performance-based awards, as well as certain other awards. On February 15, 2023, at the 2023 Annual Meeting of Stockholders, our stockholders approved an amendment to the 2014 Plan that extended the term of the 2014 Plan by five years and increased the number of shares of common stock that may be issued under the plan by 600,000 shares for a total of 1,350,000 shares.

In accordance with the 2014 Plan, the Compensation Committee has authorized grants of RSUs to certain officers and key employees of the Company. The fair value of the RSUs is based on the price of our common stock as reported on the NASDAQ Global Market on the grant dates. Typically, these grants vest over a three-year period from the date of issuance and are a blend of time-based and performance-based shares. Fifty percent of the grant is time-based and vests over a three-year period on each anniversary of the grant date, based on continued employment. The remaining fifty percent of the grant is earned based on the three-year earnings and safety performance of the Company following the grant date. At September 30, 2023, there were 292,497 RSUs outstanding. The RSUs do not have voting rights but do receive dividend equivalents upon vesting which are accrued quarterly. Additionally, the shares of common stock underlying the RSUs are not considered issued and outstanding until vested and common stock is issued.

Total RSU activity (number of shares) for the past fiscal year is summarized below:


	Number of Restricted Stock Units	Weighted Average Grant Value Per Share
Outstanding at September 30, 2022	239,862	$	26.11
Granted	147,100	21.26
Vested	(79,004)	29.24
Forfeited/cancelled	(15,461)	37.91
Outstanding at September 30, 2023	292,497	$	22.90

Restricted Stock

In February 2022, our stockholders approved an amendment to the 2014 Non-Employee Director Equity Incentive Plan (the 2014 Director Plan) that extended the term of the 2014 Director Plan by ten years and increased the number of shares of common stock that may be issued under the 2014 Director Plan by 200,000 shares for a total of 350,000 shares. The plan is administered by the Compensation Committee. Eligibility to participate in the plan is limited to those individuals who are members of the Board of Directors of the Company and who are not employees of the Company or any affiliate of the Company.

Under the terms of the 2014 Director Plan, the maximum number of shares that may be granted during any calendar year to any individual is 12,000 shares. The total number of shares that may be issued for awards to any single participant during a calendar year for other stock-based awards (excluding stock options and stock appreciation rights) is 4,000 shares. The Compensation Committee has determined that each non-employee director will receive 2,400 restricted shares of the Company’s common stock annually. Fifty percent of the restricted stock granted to each of our non-employee directors vests immediately, while the remaining fifty percent vests on the anniversary of the grant date. Compensation expense is recognized immediately for the first fifty percent of the restricted stock granted, while compensation expense for the remaining fifty percent is recognized over the remaining vesting period.

Under this 2014 Director Plan, in February 2023, 16,800 shares of restricted stock were issued to our non-employee directors at a price of $43.22 per share. In February 2022, we issued 16,800 shares of restricted stock to our non-employee directors at a price of $23.09 per share. The total number of shares of common stock available for future awards under the 2014 Director plan was 190,600 shares as of September 30, 2023. At September 30, 2023 and 2022, there were 8,400 shares and 7,200 shares, respectively, of unvested restricted stock outstanding.

Compensation Expense

Total compensation expense related to restricted stock grants under all plans was $0.6 million, $0.4 million and $0.5 million for the years ended September 30, 2023, 2022 and 2021, respectively. Total compensation expense related to RSUs under all plans was $4.0 million, $3.7 million and $2.0 million for the years ended September 30, 2023, 2022 and 2021, respectively.

We record the amortization of non-vested restricted stock and restricted stock units as an increase to additional paid-in capital. As of September 30, 2023 and 2022, amounts of deferred compensation expense not yet recognized related to non-vested stock and RSUs totaled $1.4 million and $1.2 million, respectively. As of September 30, 2023, the total weighted average remaining contractual life of our non-vested restricted stock and RSUs is approximately six months and 1.5 years, respectively.

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Deferred Tax Assets:
Net operating loss	$ 7,432	$ 10,186
Depreciation and amortization	4,573	0
Deferred compensation	2,274	1,897
Stock-based compensation	1,555	1,083
Credit carryforwards	1,378	1,332
Uniform capitalization and inventory	1,253	1,506
Reserve for accrued employee benefits	988	872
Warranty accrual	752	559
Other	317	506
Deferred tax assets	20,522	17,941
Deferred Tax Liabilities:
Depreciation and amortization	0	(3,764)
Retention and other	(1,491)	(1,229)
Deferred tax liabilities	(1,491)	(4,993)
Less: valuation allowance	(1,967)	(3,787)
Net deferred income tax asset	$ 17,064	$ 9,161

Detail of Selected Balance Sheet Accounts - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	$ 243,312	$ 235,327
Less: Accumulated depreciation	(145,687)	(136,699)
Total property, plant and equipment, net	97,625	98,628
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	21,526	21,299
Buildings and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	$ 121,454	120,506
Buildings and improvements \| Minimum
Property, Plant and Equipment [Line Items]
Asset lives	3 years
Buildings and improvements \| Maximum
Property, Plant and Equipment [Line Items]
Asset lives	39 years
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	$ 92,477	88,213
Machinery and equipment \| Minimum
Property, Plant and Equipment [Line Items]
Asset lives	3 years
Machinery and equipment \| Maximum
Property, Plant and Equipment [Line Items]
Asset lives	15 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	$ 3,726	3,581
Furniture and fixtures \| Minimum
Property, Plant and Equipment [Line Items]
Asset lives	3 years
Furniture and fixtures \| Maximum
Property, Plant and Equipment [Line Items]
Asset lives	10 years
Construction in process
Property, Plant and Equipment [Line Items]
Property, plant and equipment gross	$ 4,129	$ 1,728

Business and Organization	12 Months Ended
Business and Organization	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Organization	Business and Organization Powell Industries, Inc. (we, us, our, Powell or the Company) was incorporated in the state of Delaware in 2004 as a successor to a Nevada company incorporated in 1968. The Nevada company was the successor to a company founded by William E. Powell in 1947, which merged into the Company in 1977. Our major subsidiaries, all of which are wholly owned, include Powell Electrical Systems, Inc.; Powell (UK) Limited; Powell Canada Inc.; and Powell Industries International, B.V. We develop, design, manufacture and service custom-engineered equipment and systems which (1) distribute, control and monitor the flow of electrical energy and (2) provide protection to motors, transformers and other electrically powered equipment. Our principal products include integrated power control room substations (PCRs®), custom-engineered modules, electrical houses (E-Houses), traditional and arc-resistant distribution switchgear and control gear, medium-voltage circuit breakers, monitoring and control communications systems, motor control centers, switches and bus duct systems. These products are designed for application voltages ranging from 480 volts to 38,000 volts. Our products are used in the oil and gas markets, onshore and offshore production, liquefied natural gas (LNG) facilities and terminals, pipeline, refineries and petrochemical plants. Additionally, we manufacture products for the electric utility, light rail traction power as well as mining and metals, pulp and paper and other municipal, commercial and other industrial markets. Our product scope includes designs tested to meet both United States (U.S.) and international standards, under both the American National Standards Institute (ANSI) and International Electrotechnical Commission (IEC). We assist customers by providing field service inspection, installation, commissioning, modification, and repair services, as well as spare parts, retrofit and retrofill components for existing systems, and replacement circuit breakers for obsolete switchgear no longer produced by the original manufacturer. We seek to establish long-term relationships with the end users of our systems as well as design and construction engineering firms contracted by those end users. We believe that our culture of safety and focus on customer satisfaction, along with our financial strength, allow us to continue to capitalize on opportunities in the industries we serve. References to Fiscal 2023, Fiscal 2022 and Fiscal 2021 used throughout these Notes to Consolidated Financial Statements relate to our fiscal years ended September 30, 2023, 2022 and 2021, respectively.

Segment Information (Tables)

12 Months Ended

Sep. 30, 2023

Segment Reporting [Abstract]

Schedule of Revenues from External Customers by Region

Revenues by country represent sales to unaffiliated customers as determined by the ultimate destination of our products and services, summarized for the last three fiscal years by region in the table below (in thousands):


	Year Ended September 30,
	2023		2022		2021
United States	$	557,934	$	404,973	$	351,422
Canada	84,090		81,218		68,655
Middle East and Africa	14,998		20,712		26,615
Asia/Pacific	6,188		4,885		8,889
Europe	26,699		17,699		13,027
Mexico, Central and South America	9,399		3,095		1,951
Total revenues	$	699,308	$	532,582	$	470,559

Schedule of Long-Lived Assets by Region

Long-lived assets by country consist of property, plant and equipment, net of accumulated depreciation and are determined based on the location of the tangible assets, summarized for the last two fiscal years in the table below (in thousands):


	September 30,
	2023		2022
Long-lived assets:
United States	$	58,514	$	58,531
Canada	35,214		36,381
United Kingdom	3,897		3,716
Total	$	97,625	$	98,628

Income Taxes - Schedule of Components of Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Current:
Federal	$ 18,129	$ 557	$ 911
State	4,036	403	472
Foreign	107	7	73
Current income tax provision	22,272	967	1,456
Deferred:
Federal	(7,458)	(154)	(1,062)
State	(1,499)	(41)	(30)
Foreign	1,110	(4,666)	97
Deferred income tax provision	(7,847)	(4,861)	(995)
Total income tax provision (benefit)	$ 14,425	$ (3,894)	$ 461

Cover - USD ($) $ in Millions	12 Months Ended
Cover - USD ($) $ in Millions	Sep. 30, 2023	Dec. 04, 2023	Mar. 31, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Sep. 30, 2023
Current Fiscal Year End Date	--09-30
Document Transition Report	false
Entity File Number	001-12488
Entity Registrant Name	Powell Industries, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	88-0106100
Entity Address, Address Line One	8550 Mosley Road
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77075-1180
City Area Code	713
Local Phone Number	944-6900
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	POWL
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 324
Entity Common Stock, Shares Outstanding		11,959,333
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement for the 2023 annual meeting of stockholders to be filed not later than 120 days after September 30, 2023, are incorporated by reference into Part III of this Form 10-K.
Entity Central Index Key	0000080420
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY

Leases - Narrative (Details)	Sep. 30, 2023	Sep. 30, 2022
Leases [Abstract]
Weighted average discount rate	3.32%	3.73%
Weighted average remaining lease term	2 years 8 months 1 day	1 year 6 months 3 days

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2023
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of Powell and our wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States (U.S. GAAP) requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying footnotes. The most significant estimates used in our consolidated financial statements affect revenue recognition and estimated cost recognition on our customer contracts, the allowance for credit losses, provision for excess and obsolete inventory, warranty accruals and income taxes. The amounts recorded for warranties, legal, income taxes, impairment of long-lived assets (when applicable), liquidated damages and other contingent liabilities require judgments regarding the amount of expenses that will ultimately be incurred. We base our estimates on historical experience, forecasts and various other assumptions, as well as the specific circumstances surrounding these contingent liabilities, in evaluating the amount of liability that should be recorded. Additionally, the recognition of deferred tax assets requires estimates related to future income and other assumptions regarding timing and future profitability because the ultimate realization of net deferred tax assets is dependent on the generation of future taxable income during periods in which temporary differences become deductible. Estimates routinely change as new events occur, additional information becomes available or operating environments change. Actual results may differ from our prior estimates.
Cash and Investments	Cash and Investments Cash and cash equivalents – Cash and cash equivalents, primarily funds held in money market savings instruments, are reported at their current carrying value, which approximates fair value due to the short-term nature of these instruments, and are included in cash and cash equivalents in our Consolidated Balance Sheets. Short-term Investments – Short-term investments include time deposits with original maturities of three months or more.
Fair Value of Financial Instruments	Fair Value of Financial Instruments Financial instruments include cash, cash equivalents, short-term investments, receivables, deferred compensation, payables and debt obligations. Except as described below, due to the short-term nature of account receivables and account payables, their book values are representative of their fair values.
Accounts Receivable	Accounts Receivable Accounts receivable are stated net of allowances for credit losses. We maintain and continually assess the adequacy of the allowance for credit losses representing our estimate for losses resulting from the inability of our customers to pay amounts due to us. This estimated allowance is based on historical experience of uncollected accounts, the level of past due accounts, the overall level of outstanding accounts receivable, information about specific customers with respect to their inability to make payments and expectations of future conditions that could impact the collectability of accounts receivable. Future changes in our customers’ operating performance and cash flows, or in general economic conditions, could have an impact on their ability to fully pay these amounts, which could have a material impact on our operating results. In most cases, receivables are not collateralized. However, we utilize letters of credit to secure payment on projects when possible.
Contract Balances and Revenue Recognition	Contract Balances The timing of revenue recognition, billings and cash collections affects accounts receivable, contract assets and contract liabilities in our Consolidated Balance Sheets. Contract assets are recorded when revenues are recognized in excess of amounts billed for fixed-price contracts as determined by the billing milestone schedule. Contract assets are transferred to accounts receivable when billing milestones have been met, or we have an unconditional right to payment. Contract liabilities typically represent advance payments from contractual billing milestones and billings in excess of revenue recognized. It is unusual to have advanced milestone payments with a term greater than one year, which could represent a financing component on the contract. Our contract assets and liabilities are reported in a net position on a contract-by-contract basis at the end of each reporting period and are generally classified as current. Revenue Recognition Our revenues are primarily generated from the manufacturing of custom-engineered products and systems under long-term, fixed-price contracts that may last from one month to several years, depending on the contract. Revenue from these contracts is generally recognized over time utilizing the cost-to-cost method. Under the cost-to-cost method, the extent of progress towards completion is measured based on the ratio of costs incurred to date to the total estimated costs at completion of the performance obligation. We believe that this method is the most accurate representation of our performance because it directly measures the value of the services transferred to the customer over time as we incur costs on our contracts. Contract costs include all direct materials, labor and indirect costs related to contract performance, which may include indirect labor, supplies, tools, repairs and depreciation costs. We also have contracts to provide field service inspection, installation, commissioning, modification, and repair services, as well as retrofit and retrofill components for existing systems. If the service contract terms give us the right to invoice the customer for an amount that corresponds directly with the value of our performance completed to date (i.e., a service contract in which we bill a fixed amount for each hour of service provided), then we recognize revenue over time in each reporting period corresponding to the amount that we have the right to invoice. Our performance obligations are satisfied as the work progresses. We also have sales orders for spare parts and replacement circuit breakers for switchgear that are obsolete or that are no longer produced by the original manufacturer. Revenues from these sales orders are recognized at the time we fulfill our performance obligation to the customer, which is typically upon shipment. Additionally, some contracts may contain a cancellation clause that could limit the amount of revenue we are able to recognize over time. In these instances, revenue and costs associated with these contracts are deferred and recognized at a point in time when the performance obligation is fulfilled. Selling and administrative costs incurred in relation to obtaining a contract are typically expensed as incurred. We periodically utilize a third-party sales agent to obtain a contract and will pay a commission to that agent. We record the full commission liability to the third-party sales agents at the order date, with a corresponding deferred asset. As the project progresses, we record commission expense based on percentage of completion rates that correlate to the project and reduce the deferred asset. Once we have been paid by the customer, we pay the commission, and the liability is reduced. Performance Obligations A performance obligation is a promise in a contract or with a customer to transfer a distinct good or service. A contract’s transaction price is allocated to each distinct performance obligation and recognized as revenue as the performance obligations are satisfied. To determine the proper revenue recognition for contracts, we evaluate whether a contract should be accounted for as more than one performance obligation or, less commonly, whether two or more contracts should be combined and accounted for as one performance obligation. This evaluation of performance obligations requires significant judgment. The majority of our contracts have a single performance obligation where multiple engineered products and services are combined into a single custom-engineered solution. Our contracts include a standard one-year assurance warranty. Occasionally, we provide service-type warranties that will extend the warranty period. These extended warranties qualify as a separate performance obligation, and revenue is deferred and recognized over the warranty period. If we determine during the evaluation of the contract that there are multiple performance obligations, we allocate the transaction price to each performance obligation using our best estimate of the standalone selling price of each distinct good or service in the contract. Remaining unsatisfied performance obligations, which we refer to as backlog, represent the estimated transaction price for goods and services for which we have a material right, but work has not been performed. Contract Estimates Actual revenues and project costs may vary from previous estimates due to changes in a variety of factors. The cost estimation process is based upon the professional knowledge and experience of our engineers, project managers and financial professionals. Factors that are considered in estimating the work to be completed and ultimate contract recovery include the availability and productivity of labor, the nature and complexity of the work to be performed, the availability of materials, and the effect of any delays on our project performance. We periodically review our job performance, job conditions, estimated profitability and final contract settlements, including our estimate of total costs and make revisions to costs and income in the period in which the revisions are probable and reasonably estimable. We bear the risk of cost overruns in most of our contracts, which may result in reduced profits. Whenever revisions of estimated contract costs and contract values indicate that the contract costs will exceed estimated revenues, thus creating a loss, a provision for the total estimated loss is recorded in that period. Variable Consideration It is common for our long-term contracts to contain variable consideration that can either increase or decrease the transaction price. Due to the nature of our contracts, estimating total cost and revenue can be complex and subject to variability due to change orders, back charges, spare parts, early completion bonuses, customer allowances and liquidated damages. We estimate the amount of variable consideration based on the expected value method, which is the sum of the probability-weighted amounts, or the most likely amount method which uses various factors including experience with similar transactions and assessment of our anticipated performance. Variable consideration is included in the transaction price if legally enforceable and to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur once the uncertainty associated with the variable consideration is resolved. Contract Modifications Contracts may be modified for changes in contract specifications and requirements. We consider contract modifications to exist when the modification either creates new or changes the enforceable rights and obligations under the contract. Most of our contract modifications are for goods and services that are not distinct from the existing performance obligation. Contract modifications result in a cumulative catch-up adjustment to revenue based on our measure of progress for the performance obligation.
Inventories	Inventories Inventories are stated at the lower of cost or net realizable value using weighted-average methods and include the cost of materials, labor and manufacturing overhead. We use estimates in determining the level of reserves required to state inventory at the lower of cost or net realizable value. Our estimates are based on market activity levels, production requirements, the physical condition of products and technological innovation. Changes in any of these factors may result in adjustments to the carrying value of inventory.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are stated at cost and are depreciated using the straight-line method over the estimated useful lives of the assets. Expenditures for repairs and maintenance are charged to expense when incurred. Expenditures for major renewals and improvements, which extend the useful lives of existing equipment, are capitalized and depreciated. Upon retirement or disposition of property, plant and equipment, the cost and related accumulated depreciation are removed from the accounts, and any resulting gain or loss is recognized in the Consolidated Statements of Operations. We review property, plant and equipment for impairment whenever events or changes in circumstances indicate that the carrying value may not be realizable. If an evaluation is required, the estimated future undiscounted cash flows associated with the asset are compared to the asset’s carrying amount to determine if recording an impairment of such asset is necessary. If an impairment is indicated, we record an impairment loss equal to the difference between the carrying value and the fair value of the long-lived asset. This requires us to make long-term forecasts of the future revenues and the costs related to the assets subject to review. Forecasts require assumptions about demand for our products and future market conditions. Estimating future cash flows requires significant judgment, and our projections may vary from cash flows eventually realized. Future events and unanticipated changes to assumptions could require a provision for impairment in a future period. The effect of any impairment would be reflected in operating income in the Consolidated Statements of Operations. In addition, we estimate the useful lives of our property, plant and equipment and periodically review these estimates to determine whether these lives are appropriate.
Income Taxes	Income Taxes We account for income taxes under the asset and liability method, based on the income tax laws and rates in the countries in which operations are conducted, and income is earned. This approach requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the carrying amounts and the tax basis of assets and liabilities. Developing our provision for income taxes requires significant judgment and expertise in federal, international and state income tax laws, regulations and strategies, including the determination of deferred tax assets and liabilities and, if necessary, any valuation allowances that may be required for deferred tax assets. In assessing the extent to which net deferred tax assets may be realized, we consider whether it is more likely than not that some portion or all of the net deferred tax assets may not be realized. The ultimate realization of net deferred tax assets is dependent on the generation of future taxable income during the periods in which those temporary differences become deductible. Estimates may change as new events occur, estimates of future taxable income during the carryforward period are reduced or increased, additional information becomes available or operating environments change, which may result in a full or partial reversal of the valuation allowance. We will continue to assess the adequacy of the valuation allowance on a quarterly basis. Our judgments and tax strategies are subject to audit by various taxing authorities. The objectives of accounting for income taxes are to recognize the amount of taxes payable or refundable for the current year and deferred tax liabilities and assets for the future tax consequences of events that have been recognized in an entity’s financial statements or tax returns. We recognize the tax benefit from an uncertain tax position only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such a position should be measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. Accounting literature also provides guidance on derecognition of income tax assets and liabilities, classification of current and deferred income tax assets and liabilities, accounting for interest and penalties associated with tax positions, and income tax disclosures. Judgment is required in assessing the future tax consequences of events that have been recognized in our financial statements or tax returns. Variations in the actual outcome of these future tax consequences could materially impact our financial statements.
Warranty Costs	Warranty Costs Estimated costs of warranties are accrued based on historical warranty claim costs in relation to current revenues. In addition, specific provisions are made when product failures are projected outside historical experience. Our standard terms and conditions of sale include a warranty for parts and service for one year. Occasionally, we provide service-type warranties that will extend the warranty period. Actual results could differ from our estimate. Projects may require, on occasion, warranty terms that are longer than our standard terms due to the nature of the project. Extended warranty terms may be negotiated and included in our contracts. The allocated revenue associated with the extended warranty is deferred and recorded as a contract liability and recognized as revenue over the extended warranty period.
Research and Development Expense	Research and Development Expense Research and development activities are directed toward the development of new products and processes as well as improvements in existing products and processes. These costs, which primarily include salaries, contract services and supplies, are expensed as incurred.
Foreign Currency Translation	Foreign Currency Translation The functional currency for our foreign subsidiaries is the local currency in which the entity is located. The financial statements of all subsidiaries with a functional currency other than the U.S. Dollar have been translated into U.S. Dollars. All assets and liabilities of foreign operations are translated into U.S. Dollars using period-end exchange rates, and all revenues and expenses are translated at average rates during the respective period. The U.S. Dollar results that arise from such translation, as well as exchange gains and losses on intercompany balances of a long-term investment nature, are included in the cumulative currency translation adjustments in accumulated other comprehensive loss in stockholders’ equity.
Stock-Based Compensation	Stock-Based Compensation We measure stock-based compensation cost at the grant date based on the fair value of the award. Compensation expense is recognized over the period during which the recipient is required to provide service in exchange for the awards, typically the vesting period. Excess income tax benefits related to stock-based compensation expense are recognized as income tax expense or benefit in the Consolidated Statements of Operations. Cash paid when directly withholding shares on an employee's behalf for tax withholding purposes is classified as a financing activity. We account for forfeitures as they occur, rather than estimate expected forfeitures.

Quarterly Information (Tables)

12 Months Ended

Sep. 30, 2023

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information

The table below sets forth the unaudited consolidated operating results by fiscal quarter for the years ended September 30, 2023 and 2022 (in thousands, except per share data):


	2023 Quarters
	First(1)		Second(2)		Third(3)		Fourth(4)		2023
Revenues	$	126,858	$	171,444	$	192,365	$	208,641	$	699,308
Gross profit	19,464		33,437		42,670		51,982		147,553
Net income (loss)	1,162		8,473		18,454		26,436		54,525
Earnings (loss) per share:
Basic	$	0.10	$	0.71	$	1.55	$	2.22	$	4.59
Diluted	$	0.10	$	0.70	$	1.52	$	2.17	$	4.50

(1) The results for the first quarter of Fiscal 2023 demonstrated normal seasonality and were negatively impacted by holidays and work schedules compared to other quarterly periods.
(2) The results for the second quarter of Fiscal 2023 were positively impacted by a project cancellation of $1.6 million.
(3) The results for the third quarter of Fiscal 2023 were positively impacted by a project cancellation of $1.7 million.
(4) The results for the fourth quarter of Fiscal 2023 were positively impacted by project cancellations of $1.0 million and the reversal of a $1.9 million valuation allowance against the U.K. net deferred tax assets.


	2022 Quarters
	First(1)		Second		Third(2)		Fourth(3)		2022
Revenues	$	106,569	$	127,854	$	135,483	$	162,676	$	532,582
Gross profit	13,436		19,083		19,059		33,440		85,018
Net income (loss)	(2,846)		(1,217)		9,061		8,739		13,737
Earnings (loss) per share:
Basic	$	(0.24)	$	(0.10)	$	0.77	$	0.74	$	1.16
Diluted	$	(0.24)	$	(0.10)	$	0.76	$	0.73	$	1.15

(1) The results for the first quarter of Fiscal 2022 demonstrated normal seasonality and were negatively impacted by holidays and work schedules compared to other quarterly periods.
(2) The results for the third quarter of Fiscal 2022 were positively impacted by the release of a $5.9 million Canadian valuation allowance and a $2.0 million pre-tax gain on the sale of a non-core business within our Canadian operations.
(3) The results for the fourth quarter of Fiscal 2022 were positively impacted by a $2.5 million settlement of a claim for cost overruns from prior years related to a U.S. based municipal transit project.

Employee Benefit Plans	12 Months Ended
Employee Benefit Plans	Sep. 30, 2023
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans Retirement Plans We have defined employee contribution plans for substantially all of our U.S. employees (401k plan) and our Canadian employees (Registered Retirement Savings Plan). We recognized expenses under these plans primarily related to matching contributions of $3.4 million, $3.0 million and $2.9 million in Fiscal 2023, 2022 and 2021, respectively. Deferred Compensation We offer a non-qualified deferred compensation plan to a select group of highly compensated individuals (as defined). The plan permits the deferral of up to 50% of a participant’s base salary and/or 100% of a participant’s annual incentive. The deferrals are held in a separate irrevocable rabbi trust (the Rabbi Trust), which has been established to administer the plan. The Rabbi Trust is intended to be used as a source of funds to match respective funding obligations to participants. The assets of the trust are subject to the claims of our creditors in the event that we become insolvent. Consequently, the Rabbi Trust qualifies as a grantor trust for income tax purposes. We make periodic payments into company-owned life insurance policies held in the Rabbi Trust to fund the expected obligations arising under this plan. Changes in the deferred compensation balance are recorded to compensation expense and reflected within the selling, general and administrative expenses line in the Consolidated Statements of Operations. The plan is not qualified under Section 401 of the Internal Revenue code. We recorded net compensation expense adjustments of $0.8 million related to this plan in Fiscal 2023 and $0.3 million in Fiscal 2022. At September 30, 2023, total assets held in the Rabbi Trust were $9.1 million and recorded in other assets and the liability was $9.1 million and recorded in deferred compensation in our Consolidated Balance Sheets. The $9.1 million of assets held in the Rabbi Trust is invested in company-owned life insurance policies. Retiree Medical Plan We have an unfunded plan that extends health benefits to retirees that are also available to active employees under our existing health plans. The current plan provides coverage for employees with at least 10 years of service who are age 55 or older but less than 65. Effective January 1, 2023, eligibility for postretirement medical benefits changed to age 60 with 10 years of continuous service. Employees who are under age 50 as of January 1, 2023 or who are hired after January 1, 2023 are no longer eligible for postretirement medical benefits. The retiree is required to pay the COBRA rate less a subsidy provided by us based on years of service at the time of retirement. The unfunded liability is recorded in other long-term liabilities and was $0.5 million as of September 30, 2023 and $0.4 million as of September 30, 2022. Our net periodic postretirement costs were immaterial for all periods presented in the Consolidated Statements of Operations. Due to the immateriality of the costs and liabilities of this plan, no further disclosure is being presented.

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480794/715-70-50-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480482/715-20-55-17

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(iv)(03)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (q)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (l)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//715/tableOfContent

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(iii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (o)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (p)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (r)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (r)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480126/715-20-S99-2

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 60
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480266/715-60-50-3

+ Details

Segment Information - Schedule of Long-Lived Assets by Geographical Areas (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	$ 97,625	$ 98,628
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	58,514	58,531
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	35,214	36,381
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	$ 3,897	$ 3,716

Leases - Maturities of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Leases [Abstract]
2024	$ 802
2025	359
2026	169
2027	142
2028	18
Thereafter	0
Total future minimum lease payments	1,490
Less: present value discount (imputed interest)	(54)
Present value of lease liabilities	$ 1,436	$ 2,322

Segment Information

12 Months Ended

Sep. 30, 2023

Segment Reporting [Abstract]

Segment Information

We manage our business as one reportable operating segment related to the development, design, manufacturing and servicing of custom-engineered equipment and systems for the distribution, control and monitoring of electrical energy.


	Year Ended September 30,
	2023		2022		2021
United States	$	557,934	$	404,973	$	351,422
Canada	84,090		81,218		68,655
Middle East and Africa	14,998		20,712		26,615
Asia/Pacific	6,188		4,885		8,889
Europe	26,699		17,699		13,027
Mexico, Central and South America	9,399		3,095		1,951
Total revenues	$	699,308	$	532,582	$	470,559


	September 30,
	2023		2022
Long-lived assets:
United States	$	58,514	$	58,531
Canada	35,214		36,381
United Kingdom	3,897		3,716
Total	$	97,625	$	98,628

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 22
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-22

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 31
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-31

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-42

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 40
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-40

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-Name Accounting Standards Codification
-Publisher FASB
-URI https://asc.fasb.org//280/tableOfContent

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 26
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-26

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 34
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-34

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-41

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-21

Reference 13: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-21

Reference 14: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 32
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482810/280-10-50-32

+ Details

Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Revenue from External Customer [Line Items]
Retention amounts included in accounts receivable	$ 7,400	$ 6,900
Retained amount expected to be collected in the next twelve months	7,200
Retained amount expected to be collected	200
Research and development expenses	$ 6,220	6,963	$ 6,670
Minimum
Revenue from External Customer [Line Items]
Long-term contract beginning	1 month
Accounts Receivable
Revenue from External Customer [Line Items]
Retention amounts included in accounts receivable	$ 7,400	$ 6,900
Other Assets
Revenue from External Customer [Line Items]
Retained amount expected to be collected	$ 200

Revenue - Contract Balances (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2023
Revenue from Contract with Customer [Abstract]
Contract assets	$ 88,351	$ 60,621
Contract liabilities	(79,857)	(279,796)
Net contract asset (liability)	8,494	(219,175)
Revenue recognized related to contract liabilities	2,500	70,500
Retention amounts included in accounts receivable	$ 6,900	7,400
Retained amount expected to be collected in the next twelve months		7,200
Retained amount expected to be collected		$ 200

Employee Benefit Plans (Details) - USD ($) $ in Millions		12 Months Ended
Employee Benefit Plans (Details) - USD ($) $ in Millions	Jan. 01, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Defined contribution plan recognized expenses		$ 3.4	$ 3.0	$ 2.9
Maximum
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Age of employee		65 years
Retiree medical plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Deferred compensation requisite service period	10 years	10 years
Unfunded liability		$ 0.5	0.4
Retiree medical plan \| Minimum
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Age of employee	50 years	55 years
Retirement age (between)	60 years
Deferred compensation plan
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Percentage of employee based salary permitted for deferral under the plan		50.00%
Percentage of employee annual bonus permitted for deferral under the plan		100.00%
Deferred compensation expense adjustment		$ 0.8	$ 0.3
Deferred compensation plan assets		9.1
Deferred compensation liability		9.1
Deferred compensation plan \| Company owned life insurance policies
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Deferred compensation plan assets		$ 9.1

CONSOLIDATED BALANCE SHEETS (PARENTHETICAL) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 273	$ 344
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	30,000,000	30,000,000
Common stock, shares issued (in shares)	12,668,001	12,588,011
Common stock, shares outstanding (in shares)	12,668,001	12,588,011
Treasury stock (in shares)	806,018	806,018

Fair Value Measurements (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Assets:
Cash and cash equivalents	$ 245,875	$ 101,954
Short-term investments	33,134	14,554
Other assets	9,117	7,730
Liabilities:
Deferred compensation	9,145	7,714
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash and cash equivalents	245,875	101,954
Short-term investments	33,134	14,554
Other assets	0	0
Liabilities:
Deferred compensation	0	0
Significant Other Observable Inputs (Level 2)
Assets:
Cash and cash equivalents	0	0
Short-term investments	0	0
Other assets	9,117	7,730
Liabilities:
Deferred compensation	9,145	7,714
Significant Unobservable Inputs (Level 3)
Assets:
Cash and cash equivalents	0	0
Short-term investments	0	0
Other assets	0	0
Liabilities:
Deferred compensation	$ 0	$ 0