Atkore (ATKR) 10-K 17 Nov 22 2022 FY Annual report Financial data

Cover

Cover - USD ($) $ in Billions	12 Months Ended
	Sep. 30, 2022	Nov. 11, 2022	Mar. 25, 2022
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Sep. 30, 2022
Current Fiscal Year End Date	--09-30
Document Transition Report	false
Entity File Number	001-37793
Entity Registrant Name	Atkore Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	90-0631463
Entity Address, Address Line One	16100 South Lathrop Avenue
Entity Address, City or Town	Harvey
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60426
City Area Code	708
Local Phone Number	339-1610
Title of 12(b) Security	Common stock, par value $0.01 per share
Trading Symbol	ATKR
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 4.4
Entity Common Stock, Shares Outstanding		39,715,917
Documents Incorporated by Reference	Portions of the registrant's proxy statement to be filed with the United States Securities and Exchange Commission in connection with the registrant's 2023 annual meeting of stockholders (the "Proxy Statement") are incorporated by reference into Part III hereof. Such Proxy Statement will be filed within 120 days of the registrant's fiscal year ended September 30, 2022.
Entity Central Index Key	0001666138
Document Fiscal Year Focus	2022
Amendment Flag	false
Document Fiscal Period Focus	FY

Audit Information

Audit Information	12 Months Ended
	Sep. 30, 2022
Audit Information [Abstract]
Auditor Name	DELOITTE & TOUCHE LLP
Auditor Location	Chicago, Illinois
Auditor Firm ID	34

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Net sales	$ 3,913,949	$ 2,928,014	$ 1,765,421
Cost of sales	2,273,924	1,802,401	1,274,107
Gross profit	1,640,025	1,125,613	491,314
Selling, general and administrative	370,044	293,019	219,496
Intangible asset amortization	36,176	33,644	32,262
Operating income	1,233,805	798,950	239,556
Interest expense, net	30,676	32,899	40,062
Loss on extinguishment of debt	0	4,202	273
Other income, net	(490)	(18,152)	(2,777)
Income before income taxes	1,203,620	780,001	201,998
Income tax expense	290,186	192,144	49,696
Net income	$ 913,434	$ 587,857	$ 152,302
Net income per share
Basic (in dollars per share)	$ 20.56	$ 12.38	$ 3.15
Diluted (in dollars per share)	$ 20.30	$ 12.19	$ 3.10

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 913,434	$ 587,857	$ 152,302
Other comprehensive (loss) income, net of tax:
Change in foreign currency translation adjustment	(23,943)	2,385	6,087
Change in unrecognized (loss) income related to pension benefit plans	2,523	11,443	(6,943)
Total other comprehensive (loss) income	(21,420)	13,828	(856)
Comprehensive income	$ 892,014	$ 601,685	$ 151,446

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Current Assets:
Cash and cash equivalents	$ 388,751	$ 576,289
Accounts receivable, less allowance for current and expected credit losses of $2,544 and $2,510, respectively	528,904	524,926
Inventories, net	454,511	285,989
Prepaid expenses and other current assets	80,654	34,248
Total current assets	1,452,820	1,421,452
Property, plant and equipment, net	390,220	275,622
Intangible assets, net	382,706	241,204
Goodwill	289,330	199,048
Right-of-use assets, net	71,035	41,113
Deferred income taxes	9,409	29,693
Other long-term assets	3,476	1,967
Total Assets	2,598,996	2,210,099
Current Liabilities:
Accounts payable	244,100	243,164
Income tax payable	5,521	72,953
Accrued compensation and employee benefits	61,273	57,437
Customer liabilities	99,447	80,324
Lease obligations	13,789	11,785
Other current liabilities	77,781	59,273
Total current liabilities	501,911	524,936
Long-term debt	760,537	758,386
Long-term lease obligations	57,975	30,236
Deferred income taxes	15,640	16,746
Other long-term liabilities	13,146	15,059
Total Liabilities	1,349,209	1,345,363
Equity:
Common stock, $0.01 par value, 1,000,000,000 shares authorized, 41,351,350 and 45,997,159 shares issued and outstanding, respectively	415	461
Treasury stock, held at cost, 260,900 and 260,900 shares, respectively	(2,580)	(2,580)
Additional paid-in capital	500,117	506,921
Retained earnings	801,981	388,660
Accumulated other comprehensive loss	(50,146)	(28,726)
Total Equity	1,249,787	864,736
Total Liabilities and Equity	$ 2,598,996	$ 2,210,099

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Statement of Financial Position [Abstract]
Accounts receivable, allowance for current and expected credit losses	$ 2,544	$ 2,510
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	41,351,350	45,997,159
Common stock, shares outstanding (in shares)	41,351,350	45,997,159
Treasury stock shares (in shares)	260,900	260,900
Cash and cash equivalents	$ 388,751	$ 576,289

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Operating activities
Net income	$ 913,434	$ 587,857	$ 152,302
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	84,415	78,557	74,470
Amortization of debt issuance costs and original issue discount	2,151	2,497	1,876
Deferred income taxes	3,054	(43,306)	4,483
Loss on extinguishment of debt	0	4,202	273
Provision for losses on accounts receivable and inventory	10,235	645	5,014
Stock-based compensation expense	17,245	17,047	13,064
Amortization of right-of-use assets	13,916	14,515	14,803
Other adjustments to net income	4,850	(208)	2,157
Changes in operating assets and liabilities, net of effects from acquisitions
Accounts receivable	17,749	(219,659)	16,920
Inventories	(160,980)	(81,544)	24,642
Prepaid expenses and other current assets	(21,718)	(6,462)	(11,164)
Accounts payable	(28,968)	98,444	(5,835)
Income taxes	(92,802)	80,291	(6,261)
Accrued and other liabilities	27,198	63,459	(32,942)
Other, net	(2,944)	(23,433)	(5,040)
Net cash provided by operating activities	786,835	572,902	248,762
Investing activities
Capital expenditures	(135,776)	(64,474)	(33,770)
Insurance proceeds for properties, plant and equipment	0	9,627	2,337
Proceeds from sale of properties, plant and equipment	779	81	3,920
Acquisitions of businesses, net of cash acquired	(307,805)	(43,195)	0
Net cash used for investing activities	(442,802)	(97,961)	(27,513)
Financing activities
Repayments of short-term debt	0	(4,000)	0
Issuance of long-term debt	0	798,000	0
Repayments of long-term debt	0	(835,120)	(40,000)
Issuance of common stock, net of taxes withheld	(24,045)	2,660	(2,972)
Repurchase of common stock	(500,161)	(135,066)
Payments for debt financing costs and fees	0	(10,930)	(3,204)
Other, net	0	0	8
Net cash used for financing activities	(524,206)	(184,456)	(61,179)
Effects of foreign exchange rate changes on cash and cash equivalents	(7,365)	1,333	986
Increase (decrease) in cash and cash equivalents	(187,538)	291,818	161,056
Cash and cash equivalents at beginning of period	576,289	284,471	123,415
Cash and cash equivalents at end of period	388,751	576,289	284,471
Supplementary Cash Flow information
Interest paid	30,529	23,726	38,791
Income taxes paid, net of refunds	379,769	155,114	50,993
Capital expenditures, not yet paid	8,653	1,094	1,278
Acquisitions of businesses, not yet paid	12,628	0	0
Operating cash flows from cash paid on operating lease liabilities	12,549	13,035	12,939
Operating lease right-of-use assets obtained in exchange for lease liabilities	$ 38,794	$ 13,538	$ 15,278

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss
Beginning balance (in shares) at Sep. 30, 2019			46,955
Balance at beginning of period at Sep. 30, 2019	$ 232,936	$ (1,053)	$ 471	$ (2,580)	$ 477,139	$ (200,396)	$ (1,053)	$ (41,698)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	152,302					152,302
Other comprehensive loss	(856)							(856)
Stock-based compensation	13,064				13,064
Issuance of common stock, net of shares withheld for tax (in shares)			846
Issuance of common stock, net of shares withheld for tax	(2,972)		$ 8		(2,980)
Repurchase of common stock (in shares)			(394)
Repurchase of common stock	(15,011)		$ (4)			(15,007)
Ending balance (in shares) at Sep. 30, 2020			47,407
Balance at end of period at Sep. 30, 2020	378,410		$ 475	(2,580)	487,223	(64,154)		(42,554)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	587,857					587,857
Other comprehensive loss	13,828							13,828
Stock-based compensation	17,047				17,047
Issuance of common stock, net of shares withheld for tax (in shares)			918
Issuance of common stock, net of shares withheld for tax	2,660		$ 9		2,651
Repurchase of common stock (in shares)			(2,328)
Repurchase of common stock	(135,066)		$ (23)			(135,043)
Ending balance (in shares) at Sep. 30, 2021			45,997
Balance at end of period at Sep. 30, 2021	864,736		$ 461	(2,580)	506,921	388,660		(28,726)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	913,434					913,434
Other comprehensive loss	(21,420)							(21,420)
Stock-based compensation	17,245				17,245
Issuance of common stock, net of shares withheld for tax (in shares)			434
Issuance of common stock, net of shares withheld for tax	(24,045)		$ 4		(24,049)
Repurchase of common stock (in shares)			(5,080)
Repurchase of common stock	(500,161)		$ (51)			(500,113)
Ending balance (in shares) at Sep. 30, 2022			41,351
Balance at end of period at Sep. 30, 2022	$ 1,249,787		$ 415	$ (2,580)	$ 500,117	$ 801,981		$ (50,146)

BASIS OF PRESENTATION AND SUMMA

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	1. BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of presentation Organization and Ownership Structure — Atkore Inc. (the “Company” or “Atkore”) is a leading manufacturer of Electrical products primarily for the non-residential construction and renovation markets and Safety & Infrastructure for the construction and industrial markets. The Electrical segment manufactures high quality products used in the construction of electrical power systems including conduit, cable, and installation accessories. The Safety & Infrastructure segment designs and manufactures solutions including metal framing, mechanical pipe, perimeter security, and cable management for the protection and reliability of critical infrastructure. The Company was incorporated in the State of Delaware on November 4, 2010 under the name Atkore International Group Inc. Atkore is the sole stockholder of Atkore International Holdings Inc. (“AIH”), which in turn is the sole stockholder of Atkore International Inc. (“AII”). Holders of common stock are entitled to cast one vote for each share held of record on all matters submitted to a vote of the stockholders. Additionally, holders of common stock are entitled to receive, on a pro rata basis, dividends and distributions, if any, that the Company’s board of directors may declare out of legally available funds. Share Repurchase Program — On February 5, 2019, the board of directors approved a share repurchase program, under which the Company may repurchase up to $50.0 million of its outstanding common stock. As of December 25, 2020, there were no authorized repurchases remaining on that program. On January 28, 2021, the board of directors approved a share repurchase program, under which the Company may repurchase up to $100.0 million of its outstanding common stock. As of September 30, 2021, there were no authorized repurchases remaining. On November 16, 2021, the board of directors approved a share repurchase program, under which the Company may repurchase up to $400 million of its outstanding common stock. On April 26, 2022, the board of directors approved an amendment to the aforementioned plan, extending it to a total repurchase of the Company’s outstanding common stock of up to $800.0 million. As of September 30, 2022, $300.0 million of repurchases remained available under the plan. On November 11, 2022, the board of directors approved an amendment to the aforementioned plan, extending it to a total repurchase authorization of the Company’s outstanding stock of $1,300 million. Basis of Presentation — The accompanying audited consolidated financial statements of the Company and all of its subsidiaries included herein have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The audited consolidated financial statements include the assets and liabilities used in operating the Company's business. All intercompany balances and transactions have been eliminated in consolidation. The results of companies acquired or disposed of are included in the audited consolidated financial statements from the effective date of acquisition or up to the date of disposal. Fiscal Periods — The Company has a fiscal year that ends on September 30. The Company's fiscal quarters typically end on the last Friday in December, March and June as it follows a 4-5-4 calendar. Use of Estimates — The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclose contingent assets and liabilities at the date of the consolidated financial statements and report the associated amounts of revenues and expenses. Actual results could differ materially from these estimates. Summary of significant accounting policies Revenue Recognition — The Company’s revenue arrangements primarily consist of a single performance obligation to transfer promised goods which is satisfied at a point in time when title, risks and rewards of ownership, and subsequently control have transferred to the customer. This generally occurs when the product is shipped to the customer, with an immaterial amount of transactions in which control transfers upon delivery. The Company primarily offers assurance-type standard warranties that do not represent separate performance obligations. The Company has certain arrangements that require it to estimate at the time of sale the amounts of variable consideration that should not be recorded as revenue as certain amounts are not expected to be collected from customers, as well as an estimate of the value of products to be returned. The Company principally relies on historical experience, specific customer agreements, and anticipated future trends to estimate these amounts at the time of sale and to reduce the transaction price. These arrangements include sales discounts and allowances, volume rebates, and returned goods. The Company records its obligations related to these items within the Customer Liabilities line on the balance sheet. The Company has elected to utilize certain practical expedients available under GAAP. The Company records amounts billed to customers for reimbursement of shipping and handling costs within revenue. Shipping and handling costs associated with outbound freight after control over a product has transferred to a customer are accounted for as fulfillment costs and are included in cost of sales. Sales taxes and other usage-based taxes are excluded from revenue. The practical expedient not to disclose information about remaining performance obligations has also been elected as these obligations have an original duration of one year or less. The Company does not evaluate whether the selling price includes a financing interest component for contracts that are less than a year. The Company also expenses costs incurred to obtain a contract, primarily sales commissions, as all obligations will be settled in less than one year. The Company typically receives payment 30 to 60 days from the point it has satisfied the related performance obligation. See Note 17, “Segment Information” for revenue disaggregated by geography and product categories. Cost of Sales — The Company includes all costs directly related to the production of goods for sale in cost of sales in the statement of operations. These costs include direct material, direct labor, production related overheads, excess and obsolescence costs, lower of cost or market provisions, freight and distribution costs, and the depreciation and amortization of assets directly used in the production of goods for sale. Selling, General and Administrative Expenses — These amounts primarily include payroll-related expenses for both administrative and selling personnel, compensation expense from stock-based awards, restructuring-related charges, third-party professional services and transactional gains or losses for foreign currency transactions, excluding the foreign exchange exposure for intercompany loan transactions, which is included in Other income, net. Cash and Cash Equivalents — The Company considers all highly liquid investments with a maturity of three months or less, when purchased, to be cash equivalents. Accounts Receivable and Allowance for current and expected credit losses — The Company carries its accounts receivable at their face amounts less an allowance for current and expected credit losses. The allowance for current and expected credit losses reflects the best estimate of current and expected losses inherent in the Company’s accounts receivable portfolio determined on the basis of historical experience, specific allowances for known troubled accounts and other available evidence. Inventories — Inventories are recorded at the lower of cost (primarily LIFO) or market value. The Company estimates losses for excess and obsolete inventory through an assessment of its net realizable value based on the aging of the inventory and an evaluation of the likelihood of recovering the inventory costs based on anticipated demand and selling price. See Note 10, “Inventories, net.” Property, Plant and Equipment — Property, plant and equipment, net, is recorded at cost less accumulated depreciation. Maintenance and repair expenditures are charged to expense when incurred. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets as follows: Buildings 4 to 40 years Building improvements 3 to 20 years Machinery and equipment 1 to 20 years Leasehold improvements Lesser of remaining term of the lease or useful life Software 2 to 10 years The internal and external costs incurred to develop internal use computer software during the application development stage of the implementation, including the design of the chosen path, are capitalized. Other costs, including expenses incurred during the preliminary project stage, training expenses, data conversion costs and expenses incurred in the post implementation stage are expensed in the period incurred. Capitalized costs are amortized ratably over the useful life of the software when the software becomes operational. Upgrades and enhancements to internal use software are capitalized only if the costs result in additional functionality. The Company does not plan to sell or market its internal use computer software to third parties. Business Combinations — The Company accounts for business combinations using the acquisition method of accounting, which requires that once control is obtained, all the assets acquired and liabilities assumed, including amounts attributable to noncontrolling interests, are recorded at their respective fair values at the date of acquisition. The determination of fair values of identifiable assets and liabilities requires estimates and the use of valuation techniques when market value is not readily available. For intangible assets acquired in a business combination, the Company typically use the income method. Significant estimates in valuing certain intangible assets include, but are not limited to, the amount and timing of future cash flows, growth rates, discount rates and useful lives. The excess of the purchase price over fair values of identifiable assets and liabilities is recorded as goodwill. Long-Lived Asset and Finite - Lived Intangible Asset Impairments — The Company reviews long-lived assets, including property, plant and equipment and finite-lived intangible assets for impairment whenever events or changes in business circumstances indicate that the carrying amount of the asset may not be fully recoverable. The Company groups assets at the lowest level for which cash flows are separately identified in order to measure an impairment. Recoverability of an asset or asset group is first measured by a comparison of the carrying amount to its estimated undiscounted future cash flows expected to be generated by the asset or asset group. If the carrying amount exceeds its estimated undiscounted future cash flows, an impairment charge is recognized as the amount by which the carrying amount of the asset or asset group exceeds the estimated fair value. If impairment is determined to exist, any related impairment loss is calculated based on the estimated fair value. Impairment losses on assets to be disposed of or held for sale, if any, are based on the estimated proceeds to be received, less costs of disposal. The Company also considers potential impairment indicators associated with other finite-lived intangible assets, including its customer relationships, patents, and non-compete agreements. An impairment is recognized if the carrying value of an asset or asset group exceeds the estimated undiscounted future cash flows expected to result from the use of the asset or asset group and its eventual disposition. The Company's key customers are primarily wholesale and national distributors. The terms of these relationships are based on purchase orders and are not contractually based. Customer relationships are amortized on a straight-line basis over their useful lives, ranging from 6 to 14 years. The Company evaluates the appropriateness of remaining useful lives based on customer attrition rates. Other intangible assets are amortized on a straight-lined basis over their estimated useful lives, ranging from 1 to 20 years. The Company did not have a triggering event during fiscal 2022, 2021 and 2020. Goodwill and Indefinite-Lived Intangible Asset Impairments — The Company assesses the recoverability of goodwill and indefinite-lived trade names on an annual basis in accordance with Accounting Standards Codification (“ASC”) 350 “Intangibles - Goodwill and Other.” The measurement date is the first day of the fourth fiscal quarter, or more frequently, if events or circumstances indicate that it is more likely than not that the fair value of a reporting unit or the respective indefinite-lived trade name is less than the carrying value. The Company can elect to perform a quantitative or qualitative test of impairment. For fiscal 2022, 2021, and 2020 the Company performed a quantitative impairment assessment for goodwill. The Company calculated the fair value of its six reporting units considering three valuation approaches: (a) the income approach; (b) the guideline public company method; and (c) the comparable transaction method. The income approach calculates the fair value of the reporting unit using a discounted cash flow approach. Internally forecasted future cash flows, which the Company believes reasonably approximate market participant assumptions, are discounted using a weighted average cost of capital (Discount Rate) developed for each reporting unit. The Discount Rate is developed using market observable inputs, as well as considering whether or not there is a measure of risk related to the specific reporting unit’s forecasted performance. The key uncertainties in these calculations are the assumptions used in determining the reporting unit’s forecasted future performance, including revenue growth and EBITDA margins, as well as the perceived risk associated with those forecasts. Fair value under the guideline public company method is determined for each reporting unit by applying market multiples for comparable public companies to the reporting unit’s financial results. Fair value under the comparable transaction method is determined based on exchange prices in actual transactions and on asking prices for controlling interests in public or private companies currently offered for sale by applying market multiples for comparable public companies to the unit’s financial results. The key uncertainties in the guideline public company method and the comparable transaction method calculations are the assumptions used in determining the reporting unit's comparable public companies, comparable transactions and the selection of the market multiples. The Company did not record any goodwill impairments in fiscal 2022, 2021, and 2020. As noted above, ASC 350 also requires that the Company test the indefinite-lived intangible assets for impairment at least annually. Under ASC 350, if the carrying value of the indefinite-lived asset is higher than its fair value, then the asset is deemed to be impaired and the impairment charge is estimated as the excess carrying value over the fair value. The Company calculated the fair value of its indefinite-lived intangible assets using the income approach, specifically the relief-from-royalty method. The relief-from-royalty method is used to estimate the cost savings that accrue to the owner of an intangible asset who would otherwise have to pay royalties or license fees on revenues earned through the use of the asset. Internally forecasted revenues, which the Company believes reasonably approximate market participant assumptions, are multiplied by a royalty rate to arrive at the estimated net after tax cost savings. The royalty rate used in the analysis is based on an analysis of empirical, market-derived royalty rates for guideline intangible assets. The net after tax cost savings are discounted using the Discount Rate. The Discount Rate is developed using market observable inputs, as well as considering whether or not there is a measure of risk related to the specific indefinite lived intangible assets' forecasted performance. The key uncertainties in these calculations are the assumptions used in determining the revenue associated with each indefinite-lived intangible asset and the royalty rate. The Company did not record any indefinite-lived asset impairments in fiscal 2022, 2021, and 2020. Fair Value Measurements — Authoritative guidance for fair value measurements establishes a three-level hierarchy that ranks the quality and reliability of information used in developing fair value estimates. The hierarchy gives the highest priority to quoted prices in active markets and the lowest priority to unobservable data. In cases where two or more levels of inputs are used to determine fair value, a financial instrument's level is determined based on the lowest level input that is considered significant to the fair value measurement in its entirety. The three levels of the fair value hierarchy are summarized as follows: Level 1-inputs are based upon quoted prices (unadjusted) in active markets for identical assets or liabilities which are accessible as of the measurement date. Level 2-inputs are based upon quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, and model-derived valuations for the asset or liability that are derived principally from or corroborated by market data for which the primary inputs are observable, including forward interest rates, yield curves, credit risk and exchange rates. Level 3-inputs for the valuations are unobservable and are based on management's estimates of assumptions that market participants would use in pricing the asset or liability. The fair values are therefore determined using model-based techniques such as option pricing models and discounted cash flow models. Income Taxes and Uncertain Tax Positions — The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax basis of assets and liabilities using enacted tax rates in effect for the year it is expected the differences will reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period of the enactment date. The Company periodically assesses the realizability of the deferred tax assets. In making this determination management considers all available evidence, both positive and negative, including earnings history, expectations of future taxable income and available tax planning strategies. A valuation allowance is recorded to reduce the Company’s deferred tax assets to the amount that is considered more likely than not to be realized. Changes in the required valuation allowance are recorded in income in the period such determination is made. Certain tax positions may be considered uncertain requiring an assessment of whether an allowance should be recorded. Provisions for uncertain tax positions provide a recognition threshold based on an estimate of whether it is more likely than not that a position will be sustained upon examination. The Company measures its uncertain tax positions as the largest amount of benefit that is greater than a 50% likelihood of being realized upon examination. Interest and penalties related to unrecognized tax benefits are recorded as a component of income tax expense. See Note 7, “Income Taxes.” On December 22, 2017, “H.R.1,” also known as the Tax Cuts and Jobs Act (“TCJA”) was signed into law. As part of the enactment of TCJA, the Company recorded a global intangible low-taxed income (“GILTI”) provision for the first time beginning in fiscal 2019. The GILTI provision of TCJA requires certain income earned by controlled foreign corporations (“CFCs”) to be included currently in the gross income of the CFCs controlling U.S. shareholder. In accordance with accounting standards applicable to income taxes, there is allowed an accounting policy choice of either (1) treating taxes due on U.S. inclusions in taxable income related to GILTI as a current period expense when incurred (the “period cost method”) or (2) factoring such amounts into the Company’s measurement of its deferred taxes (the “deferred method”). The Company has elected the period method. On August 16, 2022, the Inflation Reduction Act of 2022 (“IRA”) was enacted into law. The IRA contains significant tax law changes, including a corporate alternative minimum tax of 15% on adjusted financial statement income, which if applicable for the Company would be effective beginning October 1, 2023, a 1% excise tax on stock repurchases after December 31, 2022, and various tax incentives which include, but are not limited to, credits related to the manufacturing of equipment used in solar powered energy which will take effect January 1, 2023. The Company is currently evaluating this legislation and determining what impact it would have on the Company’s financial statements. Leases — Starting in fiscal 2020, as a result of the adoption of ASC 842 “Leases,” the Company recognizes if an arrangement is a lease at the inception of the contract. The Company determines which party has the right to control an asset during the contract term and recognizes a Right of Use (“ROU”) asset and lease obligations based on the present value of the future minimum lease payments over the term of the lease. Refer to Note 2, “Leases” for further discussion of the Company’s accounting policy for leases. Translation of Foreign Currency — For the Company's non-U.S. subsidiaries that report in a functional currency other than United States dollars, assets and liabilities are translated into United States dollars using period end exchange rates. Revenue and expenses are translated at the monthly average exchange rates in effect during the reporting period. Foreign currency translation adjustments are included as a component of accumulated other comprehensive loss within the consolidated statements of comprehensive income. Recent Accounting Pronouncements A summary of recently adopted Accounting Standards Update ("ASU")s are as follows. Adoption dates are on the first day of the fiscal year indicated below, unless otherwise specified. Adopted Guidance ASU Description of ASU Impact to Atkore Adoption Date 2019-12 Simplifying the accounting for income taxes (Topic 740) The ASU eliminates certain existing exceptions related to the general approach in ASC 740 relating to franchise taxes, reducing complexity in the interim period accounting for year to date loss limitations and changes in tax laws and clarifying the accounting for transactions outside of a business combination that result in a step up in the tax basis of goodwill. The Company adopted this standard in the first quarter of 2022. The adoption of the standard did not have a material impact on the Company ’ s consolidated financial statements. 2022

LEASES

LEASES	12 Months Ended
	Sep. 30, 2022
Leases [Abstract]
LEASES	2. LEASES The Company engages in leasing transactions to meet the needs of the business. The Company leases certain manufacturing facilities, warehouses and distribution centers, office space, forklifts, vehicles and other machinery and equipment. The determination to lease, rather than purchase, an asset is primarily contingent upon capital requirements, duration of the forecasted business investment, and asset availability. The Company determines if an arrangement is a lease at inception and all arrangements deemed to be leases are subject to an assessment to determine the classification between finance and operating leases. The Company's significant assumptions and judgments in determining whether a contract is or contains a lease include establishing whether the supplier has the ability to use other assets to fulfill its service or whether the terms of the agreement enable the Company to control the use of a dedicated property, plant and equipment asset during the contract term. In the majority of the Company's contracts where it must identify whether a lease is present, it is readily determinable that the Company controls the use of the assets and obtains substantially all of the economic benefit during the term of the contract. In those contracts where identification is not readily determinable, the Company has determined that the supplier has either the ability to use another asset to provide the service or the terms of the contract give the supplier the rights to operate the asset at its discretion during the term of the contract, in which case the arrangement would not constitute a lease. Right-of-use assets and lease obligations are recognized based on the present value of the future minimum lease payments over the lease term as of the commencement date. The Company’s lease agreements have terms that include both lease and non-lease components. Lease component fees are included in the present value of future minimum lease payments. Conversely, non-lease components are not subject to capitalization and are expensed as incurred. Per ASC 842 “Leases,” the contractual interest rate is used to calculate the present value of the future minimum lease payments. However, the majority of the Company’s leases do not provide an implicit rate. Therefore, the Company's significant assumption and judgments in determining the discount rate include determining the incremental borrowing rate. The Company’s incremental borrowing rates are based on the term of the lease, the economic environment of the lease and the effect of collateralization. The valuation of the ROU asset also includes lease payments made in advance of the lease commencement date and initial direct costs incurred to secure the lease and is reduced for lease incentives. The lease terms include options to extend or terminate the lease when it is reasonably certain the Company will exercise the options. Leases with an initial term of 12 months or less are classified as short-term leases and are not recorded on the consolidated balance sheets. The lease expense for short-term leases is recognized on a straight-line basis over the lease term. The Company has certain leasing agreements, related to leased vehicles available to our sales personnel, that contain guaranteed residual value terms, which are not expected to be triggered. The Company’s leasing portfolio does not contain any material restrictive covenants. Leases (in thousands) September 30, 2022 September 30, 2021 Assets Operating lease assets $ 68,715 $ 38,569 Finance lease assets 5,209 4,966 Right-of-use assets, at cost $ 73,924 $ 43,535 Less: accumulated amortization (2,889) (2,422) Right-of-use assets, net $ 71,035 $ 41,113 Liabilities Current liabilities: Current portion of operating lease liabilities $ 12,777 $ 10,873 Current portion of finance lease liabilities 1,012 912 Current lease obligations $ 13,789 $ 11,785 Noncurrent liabilities: Operating lease liabilities $ 56,601 $ 28,434 Finance lease liabilities 1,374 1,802 Long-term lease obligations $ 57,975 $ 30,236 Total lease obligations $ 71,764 $ 42,021 Lease Cost The following table summarizes lease costs by type of cost for the fiscal year ended September 30, 2022, and the fiscal year ended September 30, 2021. In the consolidated statements of operations, cost of sales and selling, general and administrative expenses included lease costs of $15,583 and $3,732 for the fiscal year ended September 30, 2022 and $14,536 and $2,781 for the fiscal year end September 30, 2021. Fiscal year ended (in thousands) September 30, 2022 September 30, 2021 Amortization of right-of-use assets $ 13,916 $ 14,515 Interest on lease liabilities 71 49 Variable lease costs 2,471 938 Short term lease costs 2,857 1,815 Total lease costs $ 19,315 $ 17,317 Maturity of Lease Liabilities The Company's maturity analysis of its lease liabilities as of September 30, 2022 is as follows: (in thousands) Financing Leases Operating Leases 2023 $ 1,068 $ 15,259 2024 796 13,651 2025 443 11,023 2026 241 9,416 2027 23 7,769 2028 and after — 19,277 Total lease payments $ 2,571 $ 76,395 Less: Interest (185) (7,017) Present value of lease liabilities $ 2,386 $ 69,378 Lease Term and Discount Rate Fiscal year ended September 30, 2022 September 30, 2021 Weighted-average remaining lease term (years) Operating leases 8.1 5.2 Finance leases 2.7 3.3 Weighted-average discount rate Operating leases 4.5 % 4.0 % Finance leases 3.0 % 2.5 %
LEASES	2. LEASES The Company engages in leasing transactions to meet the needs of the business. The Company leases certain manufacturing facilities, warehouses and distribution centers, office space, forklifts, vehicles and other machinery and equipment. The determination to lease, rather than purchase, an asset is primarily contingent upon capital requirements, duration of the forecasted business investment, and asset availability. The Company determines if an arrangement is a lease at inception and all arrangements deemed to be leases are subject to an assessment to determine the classification between finance and operating leases. The Company's significant assumptions and judgments in determining whether a contract is or contains a lease include establishing whether the supplier has the ability to use other assets to fulfill its service or whether the terms of the agreement enable the Company to control the use of a dedicated property, plant and equipment asset during the contract term. In the majority of the Company's contracts where it must identify whether a lease is present, it is readily determinable that the Company controls the use of the assets and obtains substantially all of the economic benefit during the term of the contract. In those contracts where identification is not readily determinable, the Company has determined that the supplier has either the ability to use another asset to provide the service or the terms of the contract give the supplier the rights to operate the asset at its discretion during the term of the contract, in which case the arrangement would not constitute a lease. Right-of-use assets and lease obligations are recognized based on the present value of the future minimum lease payments over the lease term as of the commencement date. The Company’s lease agreements have terms that include both lease and non-lease components. Lease component fees are included in the present value of future minimum lease payments. Conversely, non-lease components are not subject to capitalization and are expensed as incurred. Per ASC 842 “Leases,” the contractual interest rate is used to calculate the present value of the future minimum lease payments. However, the majority of the Company’s leases do not provide an implicit rate. Therefore, the Company's significant assumption and judgments in determining the discount rate include determining the incremental borrowing rate. The Company’s incremental borrowing rates are based on the term of the lease, the economic environment of the lease and the effect of collateralization. The valuation of the ROU asset also includes lease payments made in advance of the lease commencement date and initial direct costs incurred to secure the lease and is reduced for lease incentives. The lease terms include options to extend or terminate the lease when it is reasonably certain the Company will exercise the options. Leases with an initial term of 12 months or less are classified as short-term leases and are not recorded on the consolidated balance sheets. The lease expense for short-term leases is recognized on a straight-line basis over the lease term. The Company has certain leasing agreements, related to leased vehicles available to our sales personnel, that contain guaranteed residual value terms, which are not expected to be triggered. The Company’s leasing portfolio does not contain any material restrictive covenants. Leases (in thousands) September 30, 2022 September 30, 2021 Assets Operating lease assets $ 68,715 $ 38,569 Finance lease assets 5,209 4,966 Right-of-use assets, at cost $ 73,924 $ 43,535 Less: accumulated amortization (2,889) (2,422) Right-of-use assets, net $ 71,035 $ 41,113 Liabilities Current liabilities: Current portion of operating lease liabilities $ 12,777 $ 10,873 Current portion of finance lease liabilities 1,012 912 Current lease obligations $ 13,789 $ 11,785 Noncurrent liabilities: Operating lease liabilities $ 56,601 $ 28,434 Finance lease liabilities 1,374 1,802 Long-term lease obligations $ 57,975 $ 30,236 Total lease obligations $ 71,764 $ 42,021 Lease Cost The following table summarizes lease costs by type of cost for the fiscal year ended September 30, 2022, and the fiscal year ended September 30, 2021. In the consolidated statements of operations, cost of sales and selling, general and administrative expenses included lease costs of $15,583 and $3,732 for the fiscal year ended September 30, 2022 and $14,536 and $2,781 for the fiscal year end September 30, 2021. Fiscal year ended (in thousands) September 30, 2022 September 30, 2021 Amortization of right-of-use assets $ 13,916 $ 14,515 Interest on lease liabilities 71 49 Variable lease costs 2,471 938 Short term lease costs 2,857 1,815 Total lease costs $ 19,315 $ 17,317 Maturity of Lease Liabilities The Company's maturity analysis of its lease liabilities as of September 30, 2022 is as follows: (in thousands) Financing Leases Operating Leases 2023 $ 1,068 $ 15,259 2024 796 13,651 2025 443 11,023 2026 241 9,416 2027 23 7,769 2028 and after — 19,277 Total lease payments $ 2,571 $ 76,395 Less: Interest (185) (7,017) Present value of lease liabilities $ 2,386 $ 69,378 Lease Term and Discount Rate Fiscal year ended September 30, 2022 September 30, 2021 Weighted-average remaining lease term (years) Operating leases 8.1 5.2 Finance leases 2.7 3.3 Weighted-average discount rate Operating leases 4.5 % 4.0 % Finance leases 3.0 % 2.5 %

ACQUISITIONS

ACQUISITIONS	12 Months Ended
	Sep. 30, 2022
Business Combination and Asset Acquisition [Abstract]
ACQUISITIONS	3. ACQUISITIONS From time to time, the Company enters into strategic acquisitions in an effort to better service existing customers and to attain new customers. The Company had no acquisitions in fiscal 2020. Fiscal 2022 On August 31, 2022, Atkore International Inc., and Atkore HDPE, LLC, wholly-owned subsidiaries of the Company, acquired the outstanding stock of two separate, but related, companies doing business as Cascade Poly Pipe & Conduit (“Cascade”) and Northwest Polymers, for a total purchase price of $62,100, of which $52,738 was paid at closing and an additional purchase price payable of $9,362 was accrued. Cascade is a manufacturer specializing in smooth wall HDPE conduit made from recycled materials, primarily serving the telecommunications, utility and datacom markets. Northwest Polymers is a leading recycler of PVC, HDPE and other plastics and a strategic supply partner to Cascade and other manufacturers. The purchase price allocation has not been finalized as the Company is finalizing working capital, inventory, intangible assets, deferred tax assets and liabilities and fixed asset fair values. On June 22, 2022, Atkore International Inc., a wholly-owned subsidiary of the Company acquired all of the outstanding stock of United Poly Systems, LLC (“United Poly”), for a purchase price of $227,234. United Poly is a manufacturer of high density polyethylene (“HDPE”) pressure pipe and conduit, primarily serving the telecommunications, water infrastructure, renewables and energy markets. The purchase price allocation has not been finalized as the Company is finalizing inventory, intangible assets, deferred tax assets and liabilities fair values. On May 19, 2022, Allied Tube and Conduit Corporation, wholly-owned subsidiary of the Company acquired the assets of Talon Products, LLC (“Talon”), for a purchase price of $4,193. Included in Talon’s purchase price is a purchase price payable of $402. Talon is a manufacturer of non-metallic, injection molded cable cleats, primarily serving the power distribution markets. The Company finalized the purchase price allocation of Talon in the fourth quarter of fiscal 2022. On December 21, 2021, Atkore HDPE, LLC and Allied Tube and Conduit Corporation, wholly-owned subsidiaries of the Company, acquired the assets of Four Star Industries LLC (“Four Star”), for a purchase price of $23,195. Four Star is a manufacturer of HDPE conduit, primarily serving the telecommunications, utility, infrastructure and datacom markets. The Company finalized the purchase price allocation of Four Star in the third quarter of fiscal 2022. On December 20, 2021, Columbia-MBF Inc., a wholly-owned subsidiary of the Company acquired all of the outstanding stock of Sasco Tubes & Roll Forming Inc. (“Sasco”), for a purchase price of $16,184, of which $13,320 was paid at closing and an additional purchase price payable of $2,864 was accrued. Sasco is a Canadian manufacturer of metal framing and related products serving the electrical, mechanical, construction and solar industries. The Company finalized the purchase price allocation of Sasco in the third quarter of fiscal 2022. The acquisitions in fiscal 2022 were funded using cash-on-hand. The Company incurred approximately $3,424 in acquisition-related expenses for these acquisitions, which were recorded as a component of selling, general and administrative expenses. The purchase price was allocated to tangible and intangible assets acquired and liabilities assumed, based on their fair values. The following table summarizes the Level 3 fair values assigned to the net assets acquired and liabilities assumed as of the acquisition date for fiscal 2022: (in thousands) United Poly Other Total Fair value of consideration transferred: Cash consideration $ 227,234 $ 93,044 $ 320,278 Purchase price payable — 12,628 12,628 Working Capital Adjustment — — — Total consideration transferred $ 227,234 $ 105,672 $ 332,906 Fair value of assets acquired and liabilities assumed: Cash 11,639 126 11,765 Accounts receivable 23,679 9,291 32,970 Inventories 13,455 8,111 21,566 Intangible assets 128,840 54,330 183,170 Fixed assets 13,648 8,533 22,181 Accounts payable (11,940) (5,086) (17,026) Income taxes (15,542) (2,075) (17,617) Other (1,742) 244 (1,498) Net assets acquired 162,037 73,474 235,511 Excess purchase price attributed to goodwill acquired $ 65,197 $ 32,198 $ 97,395 The Company estimates $31.1 million of the goodwill recognized by the fiscal 2022 acquisitions is deductible for tax purposes, $11.7 million that relates to United Poly and $19.4 million that relates to Cascade and Northwest Polymer. The Company estimates Goodwill recognized from the acquisitions in fiscal 2022 consists largely of the synergies and economies of scale from integrating this company with existing businesses. The following table summarizes the fair value of intangible assets as of the acquisition date: United Poly Other (in thousands) Fair Value Weighted Average Useful Life (Years) Fair Value Weighted Average Useful Life (Years) Customer relationships $ 111,700 11 $ 50,020 9 Other 17,140 8 4,310 8 Total intangible assets $ 128,840 $ 54,330 The following table presents unaudited pro forma results of operations for the Company and all companies acquired in fiscal 2022 as if those acquisitions had occurred on October 1, 2020. The results presented below are for the fiscal years ended: Fiscal year ended (in thousands) September 30, 2022 September 30, 2021 Pro forma net sales $ 4,060,993 $ 3,048,378 Pro forma net income 920,022 584,754 The pro forma condensed financial information is presented for illustrative purposes only and does not indicate the actual financial results of the Company if the closing of the acquisitions in the current year had been completed on October 1, 2020, nor is it indicative of the results of operations in future periods. Included in the unaudited pro forma financial information for the years ended September 30, 2022 and September 30, 2021 were pro forma adjustments to reflect the results of operations of the acquisitions in the current year as though those acquisitions were completed as of October 1, 2020, as well as the impact of amortizing certain acquisition accounting adjustments such as amortizable intangible assets. The pro forma financial information neither indicates the impact of possible business model changes nor considers any potential impact of current market conditions, expense efficiencies or other factors. Net sales and net income of the acquired companies are included in the consolidated statement of operations for the year ended September 30, 2022 for the post-acquisition period. Fiscal 2021 On February 24, 2021, Atkore Southwest, LLC, a wholly-owned subsidiary of the Company acquired the assets of FRE Composites USA Inc. and separately the Company acquired all of the outstanding stock of FRE Composites Inc., collectively described as FRE Composites Group (“FRE Composites”), for a purchase price of $36,993, net of cash received. FRE Composites is a leading manufacturer of fiberglass conduit for the electrical and industrial market. The purchase price was allocated to tangible and intangible assets acquired and liabilities assumed, based on their fair values. On October 22, 2020, Atkore Plastics Southeast, LLC, a wholly-owned subsidiary of the Company acquired the assets of Queen City Plastics, Inc. (“Queen City Plastics”), a leading manufacturer of PVC conduit, elbows and fittings for the electrical market. The purchase price was allocated to tangible assets acquired and liabilities assumed based on their fair values. The purchase price of $6,214 was deemed immaterial to the Company. The acquisitions in fiscal 2021 were funded using cash-on-hand. The Company incurred approximately $667 in acquisition-related expenses for these acquisitions, which were recorded as a component of selling, general and administrative expenses. The purchase price for FRE Composites, which was finalized during the fourth quarter of fiscal 2021, was allocated to tangible and intangible assets acquired and liabilities assumed, based on their fair values. The following table summarizes the Level 3 fair values assigned to the net assets acquired and liabilities assumed as of the acquisition date for fiscal 2021: (in thousands) FRE Composites Fair value of consideration transferred: Cash consideration $ 36,993 Fair value of assets acquired and liabilities assumed: Cash 437 Accounts receivable 2,163 Inventories 3,355 Intangible assets 18,300 Fixed assets 8,509 Accounts payable (1,186) Income Taxes (4,293) Other (240) Net assets acquired 27,045 Excess purchase price attributed to goodwill acquired $ 9,948 The Company estimates $1.6 million of the goodwill recognized from the FRE Composites acquisition is deductible for tax purposes. The goodwill consists largely of the synergies and economies of scale from integrating FRE Composites with existing businesses. The following table summarizes the fair value of intangible assets as of the acquisition date: FRE Composites ($ in thousands) Fair Value Weighted Average Useful Life (Years) Customer relationships $ 14,700 12.0 Other 3,600 6.0 Total intangible assets $ 18,300

POSTRETIREMENT BENEFITS

POSTRETIREMENT BENEFITS	12 Months Ended
	Sep. 30, 2022
Retirement Benefits [Abstract]
POSTRETIREMENT BENEFITS	4. POSTRETIREMENT BENEFITS The Company has a number of non-contributory and contributory defined benefit retirement plans covering certain United States employees. Net periodic pension benefit cost is based on periodic actuarial valuations that use the projected unit credit method of calculation and is charged to the statements of operations on a systematic basis over the expected average remaining service lives of current participants. The benefits under the defined benefit plans are based on various factors, such as years of service and compensation. For all periods presented, all defined pension benefit plans are frozen, whereby participants no longer accrue credited service. The net periodic cost for the periods presented was as follows: Fiscal Year Ended (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Interest cost 2,958 2,729 3,739 Expected return on plan assets (5,392) (6,424) (6,331) Amortization of actuarial loss 631 1,327 888 Net periodic cost $ (1,803) $ (2,368) $ (1,704) The weighted-average assumptions used to determine net periodic pension cost during the period were as follow: September 30, 2022 September 30, 2021 September 30, 2020 Discount rate 2.7 % 2.5 % 3.1 % Expected return on plan assets 4.0 % 6.2 % 6.3 % Rate of compensation increase N/a N/a N/a The change in the benefit obligations, plan assets and the amounts recognized on the consolidated balance sheets was as follows (in thousands): Change in benefit obligations: Balance as of September 30, 2020 $ 146,759 Interest cost 2,729 Actuarial loss (3,170) Benefits and administrative expenses paid (5,573) Balance as of September 30, 2021 140,745 Interest cost 2,958 Actuarial gain (36,411) Benefits and administrative expenses paid (6,090) Balance as of September 30, 2022 $ 101,202 Change in plan assets: Balance as of September 30, 2020 106,736 Actual return on plan assets 17,258 Employer contributions 19,635 Benefits and administrative expenses paid (5,573) Balance as of September 30, 2021 138,056 Actual return on plan assets (28,230) Employer contributions 188 Benefits and administrative expenses paid (6,090) Balance as of September 30, 2022 $ 103,925 Funded status: Funded status as of September 30, 2021 $ (2,689) Funded status as of September 30, 2022 $ 2,723 (in thousands) September 30, 2022 September 30, 2021 Amounts recognized in the consolidated balance sheets consist of: Pension Non-Current Assets $ 2,723 $ 1,130 Pension liabilities $ — $ (3,819) Net amount recognized $ 2,723 $ (2,689) Amounts recognized in accumulated other comprehensive loss (before income taxes) consist of: Net actuarial loss $ (23,616) $ (27,036) Total loss recognized $ (23,616) $ (27,036) Weighted-average assumptions used to determine pension benefit obligations at year end: Discount rate 5.4 % 2.7 % Rate of compensation increase N/a N/a The following table summarizes the defined benefit pension plans with accumulated benefit obligations in excess of plan assets: (in thousands) September 30, 2022 September 30, 2021 Accumulated benefit obligation $ — $ 122,655 Fair value of plan assets — 118,843 Neither plan had accumulated benefit obligations in excess of plan assets as of September 30, 2022. The following table summarizes the defined benefit pension plans with projected benefit obligations in excess of plan assets: (in thousands) September 30, 2022 September 30, 2021 Projected benefit obligation $ — $ 122,655 Fair value of plan assets — 118,843 Neither plan had projected benefit obligations in excess of plan assets as of September 30, 2022. In determining the expected return on plan assets, the Company considers the relative weighting of plan assets by class, historical performance of asset classes over long-term periods, asset class performance expectations as well as current and future economic conditions. The Company’s investment strategy for its pension plans is to manage the plans on a going-concern basis. Current investment policy is to maximize the return on assets, subject to a prudent level of portfolio risk, for the purpose of enhancing the security of benefits for participants. For the pension plans, this policy targets a 50% allocation to equity securities and a 50% allocation to debt securities. Pension plans have the following weighted-average asset allocations: Asset Category: September 30, 2022 September 30, 2021 Equity securities 50% 56% Debt securities 46% 43% Cash and cash equivalents 4% 1% Total 100% 100% The Company evaluates its defined benefit plans’ asset portfolios for the existence of significant concentrations of risk, such as investments in a single entity, industry, foreign country and individual fund manager. As of September 30, 2022, there were no significant concentrations of risk in the Company’s defined benefit plan assets. The Company’s plan assets are accounted for at fair value and are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of fair value of assets and their placement within the fair value hierarchy levels. The Company’s asset allocations are presented in the table below: September 30, 2022 September 30, 2021 (in thousands) Level 1 Level 2 Total Level 1 Level 2 Total United States equity securities $ 29,583 $ — $ 29,583 $ 48,274 $ — $ 48,274 Non-U.S. equity securities 22,913 — 22,913 28,787 — 28,787 Fixed income securities 22,639 24,794 47,433 59,488 — 59,488 Cash and cash equivalents 3,996 — 3,996 1,507 — 1,507 Total $ 79,131 $ 24,794 $ 103,925 $ 138,056 $ — $ 138,056 Equity securities consist primarily of publicly traded United States and non-U.S. equities. Publicly traded securities are valued at the last trade or closing price reported in the active market in which the individual securities are traded. Certain equity securities are held within commingled funds, which are valued at the unitized net asset value (“NAV”) or percentage of the NAV as determined by the custodian of the fund. These values are based on the fair value of the underlying net assets owned by the fund. Fixed income securities consist primarily of government and agency securities, corporate debt securities, and mortgage and other asset-backed securities. When available, fixed income securities are valued at the closing price reported in the active market in which the individual security is traded. Government and agency securities and corporate debt securities are valued using the most recent bid prices or occasionally the mean of the latest bid and ask prices when markets are less liquid. Asset-backed securities including mortgage-backed securities are valued using broker/dealer quotes when available. When quotes are not available, fair value is determined by utilizing a discounted cash flow approach, which incorporates other observable inputs such as cash flows, underlying security structure and market information including interest rates and bid evaluations of comparable securities. As of September 30, 2022 and September 30, 2021, the Company did not have any Level 3 pension assets. Certain fixed income securities are held within commingled funds, which are valued utilizing NAV as determined by the custodian of the fund. These values are based on the fair value of the underlying net assets owned by the fund. Cash and cash equivalents consist primarily of short-term commercial paper, and other cash or cash-like instruments including settlement proceeds due from brokers, stated at cost, which approximates fair value. Transfers between levels of the fair value hierarchy are recognized on the actual date of the event or circumstance giving rise to the transfer, which generally coincides with the Company’s valuation process. Contribution amounts are determined and funded based on laws and regulations and with the assistance of professionally qualified actuaries. The Company contributed $188 and $19,635 to its pension plans for the fiscal years ended September 30, 2022 and September 30, 2021. The Company anticipates that it will contribute at least the minimum required contribution of $234 to its pension plans in fiscal 2023. Benefit payments, which reflect future expected service as appropriate, are expected to be paid in each fiscal year as follows: (in thousands) 2023 $ 6,693 2024 6,893 2025 7,101 2026 7,294 2027 7,390 2028 to 2032 37,238 Defined Contribution Retirement Plans — The Company also sponsors several defined contribution retirement plans - the 401(k) matching programs. Expense for the defined contribution plans is computed as a percentage of participants’ compensation and was $4,615, $3,400 and $3,718 for the fiscal years ended September 30, 2022, September 30, 2021 and September 30, 2020, respectively. Multi-Employer Plan — The Company has a liability of $4,685 as of September 30, 2022 and $5,021 as of September 30, 2021 representing the Company’s proportionate share of a multi-employer pension plan which was exited prior to fiscal 2017.

STOCK INCENTIVE PLAN

STOCK INCENTIVE PLAN	12 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
STOCK INCENTIVE PLAN	5. STOCK INCENTIVE PLAN On November 21, 2019, the Company's board of directors approved the Atkore International Group Inc. 2020 Omnibus Incentive Plan (the “2020 Omnibus Incentive Plan”), which was subsequently approved by the Company’s shareholders on January 30, 2020. The 2020 Omnibus Incentive Plan provides for stock purchases and grants of other equity awards, including non-qualified stock options, stock purchase rights, restricted stock, restricted stock units (“RSUs”), performance shares, performance stock units (“PSUs”), stock appreciation rights, dividend equivalents and other stock-based awards to directors, officers, other employees and consultants. The 2020 Omnibus Incentive Plan replaces and succeeds the Atkore International Group Inc. 2016 Omnibus Incentive Plan (the “2016 Omnibus Incentive Plan”). The Company no longer grants awards from the 2016 Omnibus Incentive Plan. Awards previously granted under the 2016 Omnibus Incentive Plan were unaffected by the termination. A maximum of 2.0 million shares of common stock is reserved for issuance under the 2020 Omnibus Incentive Plan. All stock option awards have a ten year life. All share-based awards are expected to be fulfilled with new shares of common stock. Stock compensation expense is included in selling, general and administrative in the Company's consolidated statements of operations and was $17,245, $17,047 and $13,064 for fiscal years 2022, 2021 and 2020, respectively. The total income tax benefit recognized for share-based compensation arrangements was $1,634, $2,073 and $3,014 for fiscal years 2022, 2021 and 2020, respectively. Stock Options In accordance with ASC 718 Compensation - Stock Compensation, stock compensation expense for stock options is recorded on a straight-line basis over the requisite service period (generally the vesting period), net of actual forfeitures based on the grant-date fair value of the option under the equity accounting method. The assumptions used in the Black-Scholes option pricing model to value the options granted were as follows: Fiscal Year Ended September 30, 2022 September 30, 2021 September 30, 2020 Expected dividend yield — % — % — % Expected volatility 49 % 59 % 36 % Range of risk-free interest rates 1.40 % 0.52 % 1.67% Range of expected option lives 6 years 6 years 6 years Dividends are not paid on the Company’s common stock. For grants during fiscal year ended 2022 and 2021, the expected volatility is based on the Company’s stock price volatility. The risk-free interest rate is based on the United States Treasury yield curve in effect at the time of the grant for periods corresponding with the expected life of the options. The expected life of options is estimated using the simplified method due to limited historical exercise activity. The Company does not estimate forfeitures, which are accounted for as they occur. Stock option activity for the period September 30, 2019 to September 30, 2022 was as follows: Shares Weighted-Average Exercise Price Weighted-Average Grant Date Fair Value Aggregate Intrinsic Value Weighted-Average Remaining Contractual Term (in years) Outstanding as of September 30, 2019 1,836 12.94 $ 31,957 Granted 67 37.24 Exercised (508) 8.55 $ 14,548 Forfeited (20) 19.13 Outstanding as of September 30, 2020 1,375 15.66 $ 11,443 Granted 72 29.80 Exercised (678) 12.30 $ 33,075 Forfeited — — Outstanding as of September 30, 2021 769 19.95 $ 10.89 $ 51,441 Granted 42 105.94 $ 49.39 Exercised (98) 12.58 $ 9.84 $ 8,703 Forfeited — — Outstanding as of September 30, 2022 713 26.00 $ 13.29 38,062 5.22 Exercisable as of September 30, 2022 505 $ 18.56 $ 29,938 4.38 As of September 30, 2022, there was $948 of total unrecognized compensation expense related to non-vested options granted expected to be recognized over a weighted-average period of approximately 5.2 years. The total fair value of shares vested during fiscal years 2022, 2021 and 2020 was $1,447, $1,465 and $1,894, respectively. Cash received from stock option exercises for the fiscal years 2022, 2021 and 2020 was $1,230, $8,535 and $4,347, respectively. The actual tax benefit for the tax deductions from stock option exercises totaled $2,176, $8,228 and $3,681, respectively, for fiscal years 2022, 2021 and 2020. The Company does not settle any option exercises, under its current stock incentive plan, in cash. Restricted Stock Units Generally, RSUs granted under the 2020 Omnibus Incentive Plan vest ratably over three years. The fair value of RSU grants was based on the closing price of the Company's common stock on the date of grant. RSU compensation expense is recorded on a straight-line basis over the remaining vesting period. Changes to the Company’s nonvested RSU awards for the year ended September 30, 2022 were as follows: Shares Weighted-average grant-date fair value Nonvested as of September 30, 2019 674 $ 19.37 Granted 166 37.24 Vested (403) 19.43 Forfeited (32) 22.29 Nonvested as of September 30, 2020 405 26.44 Granted 218 32.01 Vested (229) 23.78 Forfeited (10) 28.48 Nonvested as of September 30, 2021 384 30.30 Granted 100 103.94 Vested (208) 27.40 Forfeited (14) 49.23 Nonvested as of September 30, 2022 262 $ 58.72 As of September 30, 2022, there was $7,712 of total unrecognized compensation expense related to non-vested RSUs granted, expected to be recognized over a weighted-average period of approximately 1.30 years. The total fair value of RSUs vested during fiscal years 2022, 2021 and 2020 was $20,342, $8,897 and $14,513 respectively. Performance Share Units The Company awards PSUs whose vesting is contingent upon meeting or exceeding certain market and performance conditions. The performance condition, which was based on an adjusted net income, represented 70% of the award and the market condition, which was based on Total Shareholder Return (“TSR”) of the Company's common stock relative to a peer group represented the remaining 30%. All PSUs cliff vest at the end of three years based on the satisfaction of the performance conditions. Expense for the performance condition based award is recorded when the achievement of the performance condition is considered probable of achievement and is recorded on a straight-line basis over the requisite service period. If such performance criteria are not met, no compensation cost is recognized and any recognized compensation cost is reversed. Expense for the market condition based award is recorded on a straight-line basis over the explicit service period. The grant-date fair value for the performance condition based awards represents the closing stock price on the date of grant. For the grants in fiscal 2022, 2021, and 2020, the closing stock price on the date of grant was $105.94, $29.80 and $37.24 respectively. The grant-date fair value for the market condition based awards was determined using the Monte-Carlo method. The assumptions used in the Monte-Carlo method to value the performance share awards granted during the fiscal year ended September 30, 2022 were as follows: September 30, 2022 September 30, 2021 September 30, 2020 Expected dividend yield — % — % — % Expected volatility 63 % 61 % 21% - 53% Risk free interest rates 0.83 % 0.21 % 1.59 % Expected life 3 years 3 years 3 years Fair value $122.25 $33.80 $44.22 Dividends are not paid on the Company’s common stock. For grants during fiscal year ended 2022 and 2021, the expected volatility is based on the Company’s stock price volatility. For grants during fiscal year 2020, expected volatility is based on historical volatilities of comparable companies. The risk-free interest rate is based on the United States Treasury yield curve in effect at the time of the grant for periods corresponding with the expected life of the award. The expected life of the award represents the weighted-average period of time that awards granted are expected to be outstanding, giving consideration to vesting schedules and expected exercise patterns. The Company does not estimate forfeitures, which are accounted for as they occur. Changes to the Company’s non-vested PSU awards for the year ended September 30, 2022 were as follows: Shares Weighted-average grant-date fair value Nonvested as of September 30, 2019 455 $ 21.11 Granted 115 40.43 Vested (162) 25.21 Adjustment for achieved performance upon issuance 31 21.68 Forfeited (14) 22.82 Nonvested as of September 30, 2020 425 $ 25.15 Granted 156 31.67 Vested (171) 21.55 Adjustment for achieved performance upon issuance 57 22.95 Forfeited (14) 29.43 Nonvested as of September 30, 2021 453 $ 28.07 Granted 52 113.51 Vested (381) 18.17 Adjustment for achieved performance upon issuance 190 18.17 Forfeited (1) 57.61 Nonvested as of September 30, 2022 313 $ 48.19

OTHER INCOME, NET

OTHER INCOME, NET	12 Months Ended
	Sep. 30, 2022
Other Income, Nonoperating [Abstract]
OTHER INCOME, NET	6. OTHER INCOME, NET Other income, net consisted of the following: Fiscal Year Ended (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Gain on purchase of business $ — $ (731) $ — Undesignated foreign currency derivative instruments (4,379) 2,201 1,269 Business interruption insurance recovery — (15,500) — Foreign exchange loss (gain) on intercompany loans 5,342 (1,534) (2,342) Pension-related benefits (1,803) (2,368) (1,704) Other 350 (220) — Other income, net $ (490) $ (18,152) $ (2,777)

INCOME TAXES

INCOME TAXES	12 Months Ended
	Sep. 30, 2022
Income Tax Disclosure [Abstract]
INCOME TAXES	7. INCOME TAXES On August 16, 2022, the Inflation Reduction Act of 2022 (“IRA”) was enacted into law. The IRA contains significant tax law changes, including a corporate alternative minimum tax of 15% on adjusted financial statement income, which if applicable for the Company would be effective beginning October 1, 2023, a 1% excise tax on stock repurchases after December 31, 2022, and various tax incentives which include, but are not limited to, credits related to the manufacturing of solar powered energy which will take effect January 1, 2023. The Company is currently evaluating this legislation and determining what impact it would have on the Company’s financial statements. Significant components of income before income taxes and income tax expense for the fiscal years ended September 30, 2022, September 30, 2021 and September 30, 2020 consisted of the following: (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Components of income before income taxes: United States $ 1,174,109 $ 770,350 $ 201,784 Non-U.S 29,511 9,651 214 Income before income taxes $ 1,203,620 $ 780,001 $ 201,998 Income tax expense: Current: United States: Federal $ 228,141 $ 182,105 $ 32,335 State 49,793 46,913 9,668 Non-U.S: 9,198 6,432 3,210 Current income tax expense $ 287,132 $ 235,450 $ 45,213 Deferred: United States: Federal $ 3,174 $ (35,442) $ 5,102 State 753 (7,281) 49 Non-U.S: (873) (583) (668) Deferred income (benefit) tax expense 3,054 (43,306) 4,483 Income tax expense $ 290,186 $ 192,144 $ 49,696 Differences between the statutory federal income tax rate and effective income tax rate are summarized below: (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Statutory federal tax 21 % 21 % 21 % Adjustments to reconcile to the effective income tax rate: State income taxes 3 % 4 % 4 % Stock-based compensation (1) % (1) % (2) % Other 1 % 1 % 2 % Effective income tax rate 24 % 25 % 25 % The Company’s effective tax rate for fiscal 2022 differs from the statutory rate primarily due to state income taxes of $39,759, and limitations on executive compensation of $6,996 partially offset by $11,438 of excess tax benefit from share-based compensation. The Company’s effective tax rate for fiscal 2021 differs from the statutory rate primarily due to state income taxes of $30,680, current year valuation allowance expense of $2,190 and limitations on executive compensation of $2,587 partially offset by $7,352 of excess tax benefit from share-based compensation. The Company’s effective tax rate for fiscal 2020 differs from the statutory rate primarily due to state income taxes of $7,690, valuation allowance expense of $2,099 and limitations on executive compensation of $1,243, partially offset by $4,203 of excess tax benefit from share-based compensation. Deferred income taxes result from temporary differences between the amount of assets and liabilities recognized for financial reporting and tax purposes. The components of the net deferred income tax assets are as follows: (in thousands) September 30, 2022 September 30, 2021 Deferred tax assets: Accrued liabilities and reserves $ 47,582 $ 42,932 Tax loss and credit carryforwards 17,272 16,096 Postretirement benefits 583 2,057 Inventory 29,501 36,021 Lease obligations 17,779 10,616 Other 1,079 633 $ 113,796 $ 108,355 Deferred tax liabilities: Property, plant and equipment $ (28,475) $ (21,784) Intangible assets (56,886) (43,657) Loss on investment — (5,102) Right-of-use assets, net (17,095) (10,247) Other (4,156) (3,095) $ (106,612) $ (83,885) Net deferred tax liability before valuation allowance 7,184 24,470 Valuation allowance (13,415) (11,523) Net deferred tax liability $ (6,231) $ 12,947 As of September 30, 2022, the Company has $12,942 of federal net operating loss carryforwards which do not expire and $29,094 of state net operating loss carryforwards which expire beginning in 2022 through 2036. In certain non-U.S. jurisdictions, the Company has net operating loss carryforwards of $52,250 which have an expiration period ranging from five years to unlimited. Valuation allowances have been established on net operating losses and other deferred tax assets in Luxembourg, Australia, France, China, and other foreign and United States state jurisdictions, as a result of the Company's determination that there is less than 50% likelihood that these assets will be realized. Evidence for this determination includes three year cumulative loss positions, future reversal of temporary differences, and expectations of future losses. As of September 30, 2022, and September 30, 2021, the Company had unrecognized tax benefits of $985 and $3,333 which, if recognized, would positively benefit the effective tax rate. The Company recognizes interest and penalties related to unrecognized tax benefits in income tax expense. As of September 30, 2022 and September 30, 2021, the Company had accrued interest and penalties of $77 and $260, respectively, in the consolidated balance sheets. A reconciliation of the beginning and ending amount of unrecognized tax benefit, excluding interest and penalties, is as follows: (in thousands) For the period from September 30, 2019 to September 30, 2022 Balance as of September 30, 2019 $ 794 Additions based on tax positions related to prior years 925 Additions based on tax positions related to current year 122 Settlements (227) Balance as of September 30, 2020 1,614 Additions based on tax positions related to prior years 291 Additions based on tax positions related to current year 1,658 Settlements (230) Balance as of September 30, 2021 3,333 Additions based on tax positions related to prior years 322 Additions based on tax positions related to current year 342 Settlements (3,012) Balance as of September 30, 2022 $ 985 During fiscal 2022, the balance of unrecognized tax benefits decreased by $3,012 as a result of completing state tax audits and the expiration of the statute of limitations in various state jurisdictions, partially offset by an increase of $664, primarily related to various state jurisdictions’ uncertain tax positions. The related accrued penalties and interest for uncertain tax positions decreased by $183. During fiscal 2021, the balance of unrecognized tax benefits increased by $1,949 as a result of federal and various state jurisdictions' uncertain tax positions, partially offset by a decrease of $230 as result of completing tax audits and the expiration of the statute of limitations in various state jurisdictions. The related accrued penalties and interest for uncertain tax positions increased by $72. During fiscal 2020, the balance of unrecognized tax benefits increased by $1,047 as a result of federal and various state jurisdictions’ uncertain tax positions, partially offset by a decrease of $227 as a result of completing tax audits and the expiration of the statute of limitations in various state jurisdictions. The related accrued penalties and interest for uncertain tax positions increased by $134. Many of the Company’s uncertain tax positions relate to tax years that remain subject to audit by the taxing authorities. The following tax years remain subject to examination by the major tax jurisdictions as follows: Jurisdiction Years Open to Audit United States 2019, 2020 and 2021 The Company's income tax returns are examined periodically by various taxing authorities. The Company is currently under examination in various state jurisdictions. Based on the current status of its income tax audits, the Company believes that it is reasonably possible that there would be no material changes to the unrecognized tax benefits in the next twelve months. Other Income Tax Matters — Prior to the passage of the TCJA, foreign undistributed earnings were generally subject to U.S. taxation when repatriated. The TCJA imposed a one-time transition tax on previously untaxed accumulated earnings of foreign subsidiaries. The Company has accumulated earnings and profits deficit, therefore did not record an additional tax liability for the transition tax. The TCJA adopts a new quasi-territorial tax regime that eliminates U.S income taxes on dividends from foreign subsidiaries. The Company may still be liable for foreign taxes, such as withholding taxes, if earnings are repatriated. For the fiscal year ended September 30, 2022, the Company recorded no additional liability for United States or non-U.S. income taxes on the undistributed income of subsidiaries or for unrecognized deferred tax liabilities for temporary differences related to basis differences in investments in subsidiaries, as such income is expected to be indefinitely reinvested, the investments are essentially permanent in duration, or the Company has concluded that no additional tax liability will arise as a result of the distribution of such income. For the fiscal year ended September 30, 2022, the Company did not record income tax or non-income tax expense related to the remaining foreign earnings, and did not record any deferred tax liabilities for any basis differences in investments in subsidiaries as the earnings are expected to be indefinitely reinvested, the investments are essentially permanent in duration, or the Company has concluded that there will be no additional tax liability as a result of the distribution of the income. As of September 30, 2022, certain subsidiaries had approximately $100,493 of undistributed income that the Company intends to permanently reinvest. A liability could arise if the Company's intention to permanently reinvest such income were to change and amounts are distributed by such subsidiaries or if such subsidiaries are ultimately disposed of. It is not practicable to estimate the additional income taxes related to permanently reinvested income or the basis differences related to investments in subsidiaries.

EARNINGS PER SHARE

EARNINGS PER SHARE	12 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
EARNINGS PER SHARE	8. EARNINGS PER SHARE The Company calculates basic and diluted earnings per common share using the two-class method. Under the two-class method, net earnings are allocated to each class of common stock and participating securities as if all of the net earnings for the period had been distributed. The Company's participating securities consist of share-based payment awards that contain a non-forfeitable right to receive dividends and therefore are considered to participate in undistributed earnings with common stockholders. Basic earnings per common share excludes dilution and is calculated by dividing the net earnings allocable to common stock by the weighted-average number of common stock outstanding for the period. Diluted earnings per common share is calculated by dividing net earnings allocated to common stock by the weighted-average number of shares outstanding for the period, as adjusted for the potential dilutive effect of non-participating share-based awards. The following table sets forth the computation of basic and diluted earnings per share: Fiscal Year Ended (in thousands, except per share data) September 30, 2022 September 30, 2021 September 30, 2020 Numerator: Net income $ 913,434 $ 587,857 $ 152,302 Less: Undistributed earnings allocated to participating securities 14,460 11,380 3,356 Net income available to common shareholders $ 898,974 $ 576,477 $ 148,946 Denominator: Basic weighted average common shares outstanding 43,717 46,569 47,265 Effect of dilutive securities: Non-participating employee stock options (1) 563 737 779 Diluted weighted average common shares outstanding 44,280 47,306 48,044 Basic earnings per share $ 20.56 $ 12.38 $ 3.15 Diluted earnings per share $ 20.30 $ 12.19 $ 3.10 (1) Stock options to purchase approximately 0.0 million , 0.0 million, and 0.3 million shares of common stock were outstanding during the years ended September 30, 2022, September 30, 2021, and September 30, 2020, respectively, but were not included in the calculation of diluted earnings per share as the impact of these would have been anti-dilutive.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE LOSS	12 Months Ended
	Sep. 30, 2022
Equity [Abstract]
ACCUMULATED OTHER COMPREHENSIVE LOSS	9. ACCUMULATED OTHER COMPREHENSIVE LOSS The following table presents the changes in accumulated other comprehensive loss by component, net of tax: (in thousands) Defined benefit pension items Currency translation adjustments Total Balance as of September 30, 2020 $ (30,761) $ (11,793) $ (42,554) Other comprehensive (loss) income before reclassifications 10,453 2,385 12,838 Amounts reclassified from accumulated other comprehensive loss 990 — 990 Net current period other comprehensive (loss) income 11,443 2,385 13,828 Balance as of September 30, 2021 $ (19,318) $ (9,408) $ (28,726) Other comprehensive income (loss) before reclassifications 2,051 (23,943) (21,892) Amounts reclassified from accumulated other comprehensive loss 472 — 472 Net current period other comprehensive income (loss) 2,523 (23,943) (21,420) Balance as of September 30, 2022 $ (16,795) $ (33,351) $ (50,146) The following is a summary of the amounts reclassified from accumulated other comprehensive loss to net income: Fiscal Year Ended (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Amortization of defined benefit pension items: Amortization of net loss (included within other income, net) $ 631 $ 1,327 $ 888 Tax expense (159) (337) (227) Net reclassifications for the period $ 472 $ 990 $ 661

INVENTORIES, NET

INVENTORIES, NET	12 Months Ended
	Sep. 30, 2022
Inventory Disclosure [Abstract]
INVENTORIES, NET	10. INVENTORIES, NET A majority of the Company records inventory at the lower of cost (primarily last in, first out, or “LIFO”) or market or net realizable value, as applicable. Approximately 82% and 81% of the Company's inventories are valued at the lower of LIFO cost or market at September 30, 2022 and September 30, 2021, respectively. (in thousands) September 30, 2022 September 30, 2021 Purchased materials and manufactured parts, net $ 166,038 $ 105,460 Work in process, net 61,182 35,043 Finished goods, net 227,291 145,486 Inventories, net $ 454,511 $ 285,989 Total inventories would be $64,550 higher and $108,911 higher than reported as of September 30, 2022 and September 30, 2021, respectively, if the first-in, first-out method was used for all inventories. During

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	12 Months Ended
	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT	11. PROPERTY, PLANT AND EQUIPMENT As of September 30, 2022 and September 30, 2021, property, plant and equipment at cost and accumulated depreciation were as follows: (in thousands) September 30, 2022 September 30, 2021 Land $ 22,113 $ 23,043 Buildings and related improvements 172,633 136,680 Machinery and equipment 427,460 372,503 Leasehold improvements 10,512 9,720 Software 36,884 28,288 Construction in progress 99,491 43,055 Property, plant and equipment, at cost 769,093 613,289 Accumulated depreciation (378,873) (337,667) Property, plant and equipment, net $ 390,220 $ 275,622

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	12 Months Ended
	Sep. 30, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND INTANGIBLE ASSETS	12. GOODWILL AND INTANGIBLE ASSETS Goodwill — C hanges in the carrying amount of goodwill are as follows: Segment (in thousands) Electrical Safety & Infrastructure Total Balance as of September 30, 2020 $ 144,662 $ 43,577 $ 188,239 Goodwill acquired during year 9,948 — 9,948 Exchange rate effects 861 — 861 Balance as of September 30, 2021 $ 155,471 $ 43,577 $ 199,048 Goodwill acquired during year 87,964 9,431 97,395 Exchange rate effects (6,727) (386) (7,113) Balance as of September 30, 2022 $ 236,708 $ 52,622 $ 289,330 Goodwill balances include $3,924 and $43,000 of accumulated impairment losses within the Electrical and Safety & Infrastructure segments, respectively, as of September 30, 2022 and September 30, 2021. Intangible Assets — The following table provides the gross carrying value, accumulated amortization, and net carrying value for each major class of intangible assets: September 30, 2022 September 30, 2021 (in thousands) Weighted Average Useful Life (Years) Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value Amortizable Intangible Assets: Customer relationships 11 $ 532,768 $ (267,940) $ 264,828 $ 371,048 $ (234,946) $ 136,102 Other 8 35,681 (10,602) 25,079 23,633 (11,411) 12,222 Total 568,449 (278,542) 289,907 394,681 (246,357) 148,324 Indefinite-lived Intangible Assets: Trade names 92,799 — 92,799 92,880 — 92,880 Total $ 661,248 $ (278,542) $ 382,706 $ 487,561 $ (246,357) $ 241,204 Amortization expense for the fiscal years ended September 30, 2022, September 30, 2021 and September 30, 2020 was $36,176, $33,644 and $32,262, respectively. Expected amortization expense for intangible assets over the next five years and thereafter is as follows (in thousands): 2023 $ 50,650 2024 47,457 2025 36,938 2026 32,515 2027 30,537 2028 and thereafter 91,810

DEBT

DEBT	12 Months Ended
	Sep. 30, 2022
Debt Disclosure [Abstract]
DEBT	13. DEBT Debt as of September 30, 2022 and September 30, 2021 was as follows: (in thousands) September 30, 2022 September 30, 2021 New Senior Secured Term Loan Facility due May 26, 2028 $ 371,381 $ 371,095 Senior Notes Due June 1, 2031 400,000 400,000 ABL Credit Facility — — Deferred financing costs (10,844) (12,709) Long-term debt $ 760,537 $ 758,386 During fiscal 2021, the Company made voluntary prepayments of principal on the New Senior Secured Term Loan Facility of $26,000. The voluntary prepayment on the New Senior Secured Term Loan Facility resulted in the removal of all principal payment requirements until the contractual maturity of the debt in fiscal 2028. As of September 30, 2022, future contractual maturities of long-term debt are as follows (in thousands): 2023 $ — 2024 — 2025 — 2026 — 2027 — 2028 and thereafter $ 773,000 New Senior Secured Term Loan Facility - On May 26, 2021, the Company entered into a new $400 million senior secured term loan facility (the “New Senior Secured Term Loan Facility”). The New Senior Secured Term Loan Facility will mature on May 26, 2028 and borrowings thereunder bear interest at the rate of either (x) LIBOR (with a floor of 0.50%) plus 2.00%, or (y) an alternate base rate (with a floor of 1.50%) plus 1.00%. The New Senior Secured Term Loan Facility has an annual amortization rate of 1.00%. Senior Notes - On May 26, 2021, the Company completed the issuance and sale of the $400 million aggregate principal amount of 4.25% Senior Notes due 2031 (the “Senior Notes”) in a private offering. The Senior Notes were sold only to qualified institutional buyers in compliance with Rule 144A of the Securities Act of 1933, as amended (the “Securities Act”), and to non-U.S. persons outside of the United States in compliance with Regulation S of the Securities Act. ABL Credit Facility — On August 28 2020, AII amended the ABL Credit Facility (the “Amended ABL Facility”). The amendment, among other things, extended the maturity of the facility to August 28, 2023, and increased the interest rate margins applicable to loans under the facility to (i) in the case of United States dollar-denominated loans, either (x) LIBOR plus an applicable margin ranging from 1.75% to 2.25%, or (y) an alternate base rate plus an applicable margin ranging from 0.75% to 1.25%, each based on available loan commitments or (ii) in the case of Canadian dollar-denominated loans, either (x) the BA rate plus an applicable margin ranging from 1.75% to 2.25% or (y) a Canadian prime rate plus an applicable margin ranging from 0.75% to 1.25%, each based on available loan commitments. The Amended ABL Credit Facility bears a commitment fee, payable quarterly in arrears, of 0.375% per annum. The Amended ABL Credit Facility also bears customary letter of credit fees. The revisions to the ABL Credit Facility were accounted for as a debt extinguishment, resulting in immediate expensing of unamortized financing costs of $273 for the year ended September 30, 2020. On May 26, 2021, the Company entered into an amendment to the ABL Credit Facility. The amendment (i) extends the maturity of the facility to the earlier of five years from entering into the amendment or 91 days prior to the maturity date of the New Senior Secured Term Loan Facility if at least $100 million of obligations remain outstanding under the New Senior Secured Term Loan Facility on such date (ii) decreases the interest rate margins applicable to loans under the facility to (a) in the case of United States dollar-denominated loans, either (x) LIBOR plus an applicable margin ranging from 1.25% to 1.75%, or (y) an alternate base rate plus an applicable margin ranging from 0.25% to 0.75% or (b) in the case of Canadian dollar-denominated loans, either (x) the bankers acceptance rate plus an applicable margin ranging from 1.25% to 1.75% or (y) a Canadian prime rate plus an applicable margin ranging from 0.25% to 0.75%. (iii) decreases the fee payable with respect to unutilized availability under the facility from 0.375% to 0.30%, depending on the remaining availability under the ABL Credit Facility the rate may decrease to 0.25% and (iv) made certain other changes agreed with the lenders under the ABL Credit Facility. The Company expects to transition to SOFR as the alternative base rate for both the ABL Credit Facility and New Senior Secured Term Loan in fiscal 2023. The Amended ABL Credit Facility has aggregate commitments of $325,000 and is guaranteed by AIH, the United States subsidiaries owned directly or indirectly by AII and certain other restricted subsidiaries of AII that AII causes to be a subsidiary guarantor from time to time including as of the closing date for the Amended ABL Credit Facility, Columbia-MBF, Inc., a corporation formed by amalgamation under the laws of Canada (“Columbia-MBF”). AII's availability under the ABL Credit Facility was $312,905 and $315,499 as of September 30, 2022 and September 30, 2021, respectively. Availability under the ABL Credit Facility is subject to a borrowing base equal to the sum of 85% of eligible accounts receivable plus the lesser of (i) 80% of eligible inventory of each borrower and guarantor, valued at the lower of cost and fair market value and (ii) 85% of the net orderly liquidation value of eligible inventory, subject to certain limitations. There were no borrowings outstanding under the ABL Credit Facility as of September 30, 2022 and September 30, 2021, respectively. The New Senior Secured Term Loan Facility and the ABL Credit Facility are secured by all of the assets of AII and the guarantors under such facilities. The New Senior Secured Term Loan Facility has priority over all real property, plant and equipment, intellectual property and capital stock of AII and any guarantor and any documents or instruments evidencing the foregoing assets. The ABL Credit Facility has second priority over the foregoing assets. The ABL Credit Facility has first priority over cash and cash equivalents, accounts receivable, inventory and other documents and instruments evidencing the foregoing assets. The New Senior Secured Term Loan Facility has second priority over the foregoing assets. The aforementioned debt instruments contain customary covenants typical for this type of financing, including limitations on indebtedness, restricted payments including dividends, liens, restrictions on distributions from restricted subsidiaries, sales of assets, affiliate transactions and mergers and consolidations. Many of these covenants are only applicable when the Company has surpassed certain thresholds relating to its indebtedness and availability under the ABL Credit Facility. Additionally, these debt instruments include customary events of default, including, among other things, payment default, covenant default, payment defaults and accelerations under other indebtedness, judgment defaults and bankruptcy, insolvency or reorganization affecting the Company or certain of its subsidiaries. Use of Proceeds - In fiscal 2021, the proceeds from the Senior Notes and the New Senior Secured Term Loan Facility were used to repay the remaining principal of the existing First Lien Term Loan Facility of $772.0 million and $4.0 million of accrued interest. The Company accounted for the repayment of the First Lien Term Loan Facility as an extinguishment of debt and recorded a $4.2 million loss on extinguishment of debt. The Company accounted for the amendment to the ABL Credit Facility as a modification of debt.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	14. FAIR VALUE MEASUREMENTS Certain assets and liabilities are required to be recorded at fair value on a recurring basis. The Company used forward currency contracts to hedge the effects of foreign exchange relating to certain of the Company's intercompany receivables denominated in a foreign currency. These derivative instruments expired during the year. These were not formally designated as hedges by the Company. Short-term forward currency contracts are recorded in prepaid expenses and other current assets or other current liabilities and long-term forward currency contracts are recorded in other long-term assets or other long-term liabilities in the consolidated balance sheets for the applicable period. The fair value gains and losses are included in other income, net within the consolidated statements of operations. See Note 6, “Other Income, net” for further detail. The total notional amounts of undesignated forward currency contracts were £0.0 million, £37.4 million and £43.3 million as of September 30, 2022, September 30, 2021 and September 30, 2020. Cash flows associated with derivative financial instruments are recognized in the operating section of the consolidated statements of cash flows. The fair value of forward currency contracts is calculated by reference to current forward exchange rates for contracts with similar maturity profiles. The following table presents the recurring assets and liabilities measured at fair value as of September 30, 2022 and September 30, 2021 in accordance with the fair value hierarchy: September 30, 2022 September 30, 2021 (in thousands) Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Assets Cash equivalents $ 291,757 $ — $ — $ 489,987 $ — $ — Forward currency contracts — — — — 127 — Liabilities Forward currency contracts — $ — — — $ 183 — The Company’s remaining financial instruments consist primarily of cash, accounts receivable and accounts payable whose carrying value approximate their fair value due to their short-term nature. The estimated fair value of financial instruments not carried at fair value in the consolidated balance sheets were as follows: September 30, 2022 September 30, 2021 (in thousands) Carrying Value Fair Value Carrying Value Fair Value New Senior Secured Term Loan Facility due May 26, 2028 $ 373,000 $ 370,203 $ 373,000 $ 371,486 Senior Notes due June 2031 400,000 318,912 400,000 415,828 Total debt $ 773,000 $ 689,115 $ 773,000 $ 787,314 In determining the approximate fair value of its long-term debt, the Company used the trading value among financial institutions, which were classified within Level 2 of the fair value hierarchy. The carrying value of the ABL Credit Facility approximates fair value due to it being market-linked variable rate debt.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	15. COMMITMENTS AND CONTINGENCIES The Company has obligations related to commitments to purchase certain goods. As of September 30, 2022, such obligations were $175,282 for fiscal 2023, $4,731 for fiscal 2024 and $5,600 thereafter. These amounts represent open purchase orders for materials used in production. Insurable Liabilities — The Company maintains policies with various insurance companies for its workers’ compensation, product, property, general, auto, and executive liability risks. The insurance policies that the Company maintains have various retention levels and excess coverage limits. The establishment and update of liabilities for unpaid claims, including claims incurred but not reported, is based on management's estimate as a result of the assessment by the Company's claim administrator of each claim and an independent actuarial valuation of the nature and severity of total claims. The Company utilizes a third-party claims administrator to pay claims, track and evaluate actual claims experience, and ensure consistency in the data used in the actuarial valuation. Legal Contingencies — Historically, a number of lawsuits have been filed against the Company and the Company has also received other claim demand letters alleging that the Company's anti-microbial coated steel sprinkler pipe, which the Company has not manufactured or sold for several years, is incompatible with chlorinated polyvinyl chloride and caused stress cracking in such pipe manufactured by third parties when installed together in the same sprinkler system, which the Company refers to collectively as the “Special Products Claims.” Tyco International Ltd. (“Tyco”), now Johnson Controls, Inc. (“JCI”), has a contractual obligation to indemnify the Company in respect of all remaining and future claims of incompatibility between the Company's antimicrobial coated steel sprinkler pipe and CPVC pipe used in the same sprinkler system. When Special Products Claims arise, JCI has defended and indemnified the Company as required. As of September 30, 2022, the Company believes that the range of reasonably possible losses for Special Products Claims and other product liabilities is between $1,000 and $8,000. At this time, the Company does not expect the outcome of the Special Products Claims proceedings, either individually or in the aggregate, to have a material adverse effect on its business, financial condition, results of operations or cash flows, and the Company believes that its reserves are adequate for all remaining contingencies for Special Products Claims. During the year ended September 30, 2020, one of the Company’s manufacturing facilities experienced a flood which resulted in damages to certain property, plant and equipment. This facility was covered under the Company’s property and casualty loss and business interruption insurance policies. During the year ended September 30, 2021, the Company settled the related insurance claim and received $15,500 of business interruption recovery proceeds related to this incident. The amount was recorded as other income within the consolidated statements of operations for the year ended September 30, 2021. In addition to the matters discussed above, from time to time, the Company is subject to a number of disputes, administrative proceedings and other claims arising out of the ordinary conduct of the Company's business. These matters generally relate to disputes arising out of the use or installation of the Company’s products, product liability litigation, contract disputes, patent infringement accusations, employment matters, personal injury claims and similar matters. On the basis of information currently available to the Company, it does not believe that existing proceedings and claims will have a material adverse effect on its business, financial condition, results of operations or cash flows. However, litigation is unpredictable, and the Company could incur judgments or enter into settlements for current or future claims that could adversely affect its business, financial condition, results of operations or cash flows.

GUARANTEES

GUARANTEES	12 Months Ended
	Sep. 30, 2022
Guarantees and Product Warranties [Abstract]
GUARANTEES	16. GUARANTEES The Company has outstanding letters of credit totaling $12,095 supporting workers’ compensation and general liability insurance policies and surety bonds primarily related to performance guarantees on supply agreements and construction contracts, and payment of duties and taxes totaling $26,782 as of September 30, 2022. In disposing of assets or businesses, the Company often provides representations, warranties and indemnities to cover various risks including unknown damage to the assets, environmental risks involved in the sale of real estate, liability to investigate and remediate environmental contamination at waste disposal sites and manufacturing facilities, and unidentified tax liabilities and legal fees related to periods prior to disposition. The Company does not have the ability to estimate the potential liability from such indemnities because they relate to unknown conditions. However, the Company has no reason to believe that these uncertainties would have a material adverse effect on the Company's business, financial condition, results of operations or cash flows. In the normal course of business, the Company is liable for product performance and contract completion. In the opinion of management, such obligations will not have a material adverse effect on the Company's business, financial condition, results of operations or cash flows.

SEGMENT INFORMATION

SEGMENT INFORMATION	12 Months Ended
	Sep. 30, 2022
Segment Reporting [Abstract]
SEGMENT INFORMATION	17. SEGMENT INFORMATION The Electrical segment manufactures high quality products used in the construction of electrical power systems including conduit, cable, and installation accessories. This segment serves contractors in partnership with the electrical wholesale channel. The Safety & Infrastructure segment designs and manufactures solutions including metal framing, mechanical pipe, perimeter security, and cable management for the protection and reliability of critical infrastructure. These solutions are marketed to contractors, original equipment manufacturers and end users. Both segments use Adjusted EBITDA as the primary measure of profit and loss. Segment Adjusted EBITDA is the income (loss) before income taxes, adjusted to exclude unallocated expenses, depreciation and amortization, interest expense, net, loss on extinguishment of debt, restructuring charges, impairment charges, stock-based compensation, certain legal matters, transaction costs, gain on purchase of business, gain on sale of a business and other items, such as inventory reserves and adjustments, loss on disposal of property, plant and equipment, insurance recovery related to damages of property, plant and equipment, release of indemnified uncertain tax positions, and realized or unrealized gain (loss) on foreign currency impacts of intercompany loans and related forward currency derivatives. Intersegment transactions primarily consist of product sales at designated transfer prices on an arm's-length basis. Gross profit earned and reported within the segment is eliminated in the Company’s consolidated results. Certain manufacturing and distribution expenses are allocated between the segments on a pro rata basis due to the shared nature of activities. Recorded amounts represent a proportional amount of the quantity of product produced for each segment. Certain assets, such as machinery and equipment and facilities, are not allocated to each segment despite serving both segments. These shared assets are reported within the Safety & Infrastructure segment. We allocate certain corporate operating expenses that directly benefit our operating segments, such as insurance and information technology, on a basis that reasonably approximates an estimate of the use of these services. Fiscal year ended September 30, 2022 September 30, 2021 September 30, 2020 (in thousands) External Net Sales Inter- segment Sales Adjusted EBITDA External Net Sales Inter- segment Sales Adjusted EBITDA External Net Sales Inter- segment Sales Adjusted EBITDA Electrical $ 3,013,755 $ — $ 1,273,410 $ 2,229,862 $ 3,437 $ 873,868 $ 1,267,988 $ 2,559 $ 292,809 Safety & Infrastructure 900,194 394 $ 138,390 698,152 168 $ 81,827 497,433 90 $ 67,821 Eliminations (394) — (3,605) — (2,649) Consolidated operations $ 3,913,949 $ — $ 2,928,014 $ — $ 1,765,421 $ — Capital Expenditures Total Assets (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 September 30, 2022 September 30, 2021 September 30, 2020 Electrical $ 61,721 $ 34,995 $ 16,067 $ 1,524,670 $ 1,122,835 $ 794,931 Safety & Infrastructure 38,280 22,407 15,470 618,331 482,942 255,903 Unallocated 35,775 7,072 2,233 455,995 604,322 507,691 Consolidated operations $ 135,776 $ 64,474 $ 33,770 $ 2,598,996 $ 2,210,099 $ 1,558,525 Presented below is a reconciliation of operating segment Adjusted EBITDA to Income before income taxes: Fiscal Year Ended (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Operating segment Adjusted EBITDA Electrical $ 1,273,410 $ 873,868 $ 292,809 Safety & Infrastructure 138,390 81,827 67,821 Total $ 1,411,800 $ 955,695 $ 360,630 Unallocated expenses (a) (70,010) (58,148) (33,995) Depreciation and amortization (84,415) (78,557) (74,470) Interest expense, net (30,676) (32,899) (40,062) Loss on extinguishment of debt — (4,202) (273) Stock-based compensation (17,245) (17,047) (13,064) Transaction costs (3,424) (667) (196) Other (b) (2,410) 15,826 3,428 Income before income taxes $ 1,203,620 $ 780,001 $ 201,998 (a) Represents unallocated selling, general and administrative activities and associated expenses including, in part, executive, legal, finance, human resources, information technology, business development and communications, as well as certain costs and earnings of employee-related benefits plans, such as stock-based compensation and a portion of self-insured medical costs. (b) Represents other items, such as inventory reserves and adjustments, loss on disposal of property, plant and equipment, insurance recovery related to damages of property, plant and equipment, release of indemnified uncertain tax positions and realized or unrealized gain (loss) on foreign currency impacts of intercompany loans, restructuring charges, gain on purchase of business, impairment charges, and related forward currency derivatives. The Company’s long-lived assets and net sales by geography were as follows: Long-lived assets Net sales (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 September 30, 2022 September 30, 2021 September 30, 2020 United States $ 410,263 $ 258,069 $ 203,694 $ 3,552,893 $ 2,637,118 $ 1,563,258 Other Americas 7,195 6,180 146 102,626 53,151 26,421 Europe 38,396 45,917 41,283 213,581 183,985 132,299 Asia-Pacific 5,400 6,569 1,759 44,849 53,760 43,443 Total $ 461,255 $ 316,735 $ 246,882 $ 3,913,949 $ 2,928,014 $ 1,765,421 The table below shows the amount of net sales from external customers for each of the Company’s product categories which accounted for 10% or more of consolidated net sales in any of the last three fiscal years: Fiscal Year Ended (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Metal Electrical Conduit and Fittings $ 635,481 $ 612,137 $ 484,476 Plastic Pipe and Conduit 1,479,331 893,199 308,561 Electrical Cable and Flexible Conduit 535,194 424,411 322,888 Other Electrical products 363,749 300,115 152,063 Electrical 3,013,755 2,229,862 1,267,988 Mechanical Pipe 445,453 395,289 244,902 Other Safety & Infrastructure products 454,741 302,863 252,531 Safety & Infrastructure 900,194 698,152 497,433 Net sales $ 3,913,949 $ 2,928,014 $ 1,765,421 Risks and Concentrations Concentration of Credit Risk — The Company extends credit to various customers in the retail and construction industries. Collection of trade receivables may be affected by changes in economic or other industry conditions and may, accordingly, impact the Company's overall credit risk. Although the Company generally does not require collateral, the Company performs ongoing credit evaluations of customers and maintains reserves for potential credit losses. As of September 30, 2022, one customer, CED National represented 10% of the Company’s accounts receivable, with no significant amounts past due. As of September 30, 2021, one customer, CED National represented 11% of the Company’s accounts receivable, with no significant amounts past due. For fiscal 2021, 2020 and 2019, no single customer accounted for more than 10% of sales.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	12 Months Ended
	Sep. 30, 2022
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	. SUBSEQUENT EVENTS On November 7, 2022, Atkore HDPE, LLC and Allied Tube and Conduit Corporation, wholly-owned subsidiaries of the Company, acquired the assets of Elite Polymer Solutions (“Elite Polymer”), for a purchase price of $91.6 million. Elite Polymer is a manufacturer of HDPE conduit, primarily serving the telecommunications, utility, and transportation markets. Subsequent to fiscal year end 2022, the Company has repurchased 1.7 million shares at an aggregate cost of $150.1 million. On November 11, 2022, the board of directors approved an amendment to the aforementioned plan, extending it to a total repurchase authorization of the Company’s outstanding stock of $1,300 million.

SCHEDULE I - CONDENSED FINANCIA

SCHEDULE I - CONDENSED FINANCIAL INFORMATION	12 Months Ended
	Sep. 30, 2022
Condensed Financial Information Disclosure [Abstract]
SCHEDULE I - CONDENSED FINANCIAL INFORMATION	SCHEDULE I ATKORE INC. (PARENT) CONDENSED FINANCIAL INFORMATION CONDENSED BALANCE SHEETS (in thousands, except share and per share data) September 30, 2022 September 30, 2021 Assets Investment in subsidiary $ 1,249,787 $ 864,736 Total Assets 1,249,787 864,736 Liabilities and Equity Total Liabilities $ — $ — Equity: Common stock, $0.01 par value, 1,000,000,000 shares authorized, 41,351,350 and 45,997,159 shares issued and outstanding, respectively $ 415 $ 461 Treasury stock, held at cost, 260,900 and 260,900 shares, respectively (2,580) (2,580) Additional paid-in capital 500,117 506,921 Retained earnings 801,981 388,660 Accumulated other comprehensive loss (50,146) (28,726) Total Equity 1,249,787 864,736 Total Liabilities and Equity $ 1,249,787 $ 864,736 See Notes to Condensed Financial Information SCHEDULE I ATKORE INC. (PARENT) CONDENSED FINANCIAL INFORMATION CONDENSED STATEMENTS OF OPERATIONS Fiscal Year Ended (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Equity in net income of subsidiary $ 913,434 $ 587,857 $ 152,302 Net income 913,434 587,857 152,302 Other comprehensive (loss) income of subsidiary, net of tax (21,420) 13,828 (856) Comprehensive income $ 892,014 $ 601,685 $ 151,446 See Notes to Condensed Financial Information SCHEDULE I ATKORE INC. (PARENT) CONDENSED FINANCIAL INFORMATION CONDENSED STATEMENTS OF CASH FLOWS For the Year Ended (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Cash Flows from Operating Activities: Net cash provided by operating activities $ — $ — $ — Cash Flows from Investing Activities: Distribution received from subsidiary 500,161 135,066 15,011 Distribution paid to subsidiary 24,045 (2,660) 2,972 Net cash provided by investing activities 524,206 132,406 17,983 Cash Flows from Financing Activities: Issuance of common stock, net of taxes withheld (24,045) 2,660 (2,972) Repurchase of common shares (500,161) (135,066) (15,011) Net cash used in financing activities (524,206) (132,406) (17,983) Net change in cash and cash equivalents — — — Cash and cash equivalents: Beginning — — — Ending $ — $ — $ — See Notes to Condensed Financial Information SCHEDULE I ATKORE INC. (PARENT) CONDENSED FINANCIAL INFORMATION NOTES TO CONDENSED FINANCIAL INFORMATION (dollars in thousands) 1. Description of Atkore Inc. Atkore Inc. (the “Company,” “Parent” or “Atkore”) was incorporated in the State of Delaware on November 4, 2010 under the name Atkore International Group Inc. The Company is the stockholder of Atkore International Holdings Inc. (“AIH”), which is the sole stockholder of Atkore International Inc. (“AII”). Prior to the transactions described below, all of the capital stock of AII was owned by Tyco International Ltd. (“Tyco”). The business of AII was operated as the Tyco Electrical and Metal Products (“TEMP”) business of Tyco. Atkore was initially formed by Tyco as a holding company to hold ownership of TEMP. On November 9, 2010, Tyco announced that it had entered into an agreement to sell a majority interest in TEMP to CD&R Allied Holdings, L.P. (the “CD&R Investor”), an affiliate of the private equity firm Clayton Dubilier & Rice, LLC (“CD&R”). On December 22, 2010, the transaction was completed and CD&R acquired shares of a newly created class of cumulative convertible preferred stock (the “Preferred Stock”) of the Company. The Preferred Stock initially represented 51% of the Company's outstanding capital stock (on an as-converted basis). On December 22, 2010, the Company also issued common stock (the “Common Stock”) to Tyco's wholly owned subsidiary, Tyco International Holding S.à.r.l. (“Tyco Seller”), that initially represented the remaining 49% of the Company's outstanding capital stock. Subsequent to December 22, 2010, the Company has operated as an independent, stand-alone entity. On March 6, 2014, the Company entered into a non-binding letter of intent (the “Letter of Intent”) with Tyco for the acquisition (the “Acquisition”) of 40.3 million shares of Common Stock held by Tyco Seller. On April 9, 2014, the Company paid $250,000 to Tyco Seller to redeem the shares, which were subsequently retired. The Company paid $2,000 of expenses related to the share redemption. In a separate transaction on the same date, the CD&R Investor converted its Preferred Stock and accumulated Preferred Dividends into Common Stock. As a result, Common Stock is the Company's sole issued and outstanding class of securities. The Parent has no significant operations or assets other than its indirect ownership of the equity of AII. Accordingly, the Parent is dependent upon distributions from AII to fund its obligations. However, under the terms of the agreements governing AII's borrowings, AII's ability to pay dividends or lend to Atkore Holding or the Parent, is restricted. While certain exceptions to the paying dividends or lending funds restrictions exist, these restrictions have resulted in the restricted net assets (as defined in Rule 4-08(e)(3) of Regulation S-X) of the Company's subsidiaries exceeding 25% of the consolidated net assets of the Company and its subsidiaries. Atkore Holding has no obligations to pay dividends to the Parent except to pay specified amounts to Parent in order to fund the payment of the Parent's tax obligations. 2. Basis of Presentation The accompanying condensed Parent only financial statements are required in accordance with Rule 4-08(e)(3) of Regulation S-X. The financial statements include the amounts of the Parent and its investment in its subsidiaries under the equity method and does not present the financial statements of the Parent and its subsidiaries on a consolidated basis. Under the equity method, investment in its subsidiaries is stated at cost plus contributions and equity in undistributed income (loss) of subsidiary less distributions received since the date of acquisition. These condensed Parent only financial statements should be read in conjunction with the Atkore Inc. consolidated financial statements and their accompanying notes. 3. Dividends and Distributions from Subsidiaries The Company received distributions of $500,161, $135,066, and $15,011 from its subsidiaries for the years ended September 30, 2022, September 30, 2021 and September 30, 2020, respectively. The distributions received in fiscal 2021, 2020 and 2019 were used to repurchase shares of the Company's common stock. These dividends were permissible under an exception to the net asset restrictions of the agreements governing AII's borrowings, which allow for dividend payments from AII to AIH or the Parent for the purpose of repurchasing shares of Parent's common stock.

SCHEDULE II - VALUATION AND QUA

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS	12 Months Ended
	Sep. 30, 2022
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS	SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS (in thousands) Balance at Beginning of Year Additional (Charges)/Benefit to Income Write offs and Other Balance at End of Year Accounts Receivable Allowance for Current and Expected Credit Losses: For the fiscal year ended: 2022 $ (2,510) (1,276) 1,242 $ (2,544) 2021 $ (3,167) (339) 996 $ (2,510) 2020 $ (2,608) (1,990) 1,431 $ (3,167) Deferred Tax Valuation Allowance: For the fiscal year ended: 2022 $ (11,523) (5,265) 3,373 $ (13,415) 2021 $ (10,203) (2,190) 870 $ (11,523) 2020 $ (7,764) (2,047) (392) $ (10,203)

BASIS OF PRESENTATION AND SUM_2

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation — The accompanying audited consolidated financial statements of the Company and all of its subsidiaries included herein have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”).
Fiscal Periods	Fiscal Periods
Use of Estimates	Use of Estimates
Revenue Recognition	Revenue Recognition — The Company’s revenue arrangements primarily consist of a single performance obligation to transfer promised goods which is satisfied at a point in time when title, risks and rewards of ownership, and subsequently control have transferred to the customer. This generally occurs when the product is shipped to the customer, with an immaterial amount of transactions in which control transfers upon delivery. The Company primarily offers assurance-type standard warranties that do not represent separate performance obligations. The Company has certain arrangements that require it to estimate at the time of sale the amounts of variable consideration that should not be recorded as revenue as certain amounts are not expected to be collected from customers, as well as an estimate of the value of products to be returned. The Company principally relies on historical experience, specific customer agreements, and anticipated future trends to estimate these amounts at the time of sale and to reduce the transaction price. These arrangements include sales discounts and allowances, volume rebates, and returned goods. The Company records its obligations related to these items within the Customer Liabilities line on the balance sheet. The Company has elected to utilize certain practical expedients available under GAAP. The Company records amounts billed to customers for reimbursement of shipping and handling costs within revenue. Shipping and handling costs associated with outbound freight after control over a product has transferred to a customer are accounted for as fulfillment costs and are included in cost of sales. Sales taxes and other usage-based taxes are excluded from revenue. The practical expedient not to disclose information about remaining performance obligations has also been elected as these obligations have an original duration of one year or less. The Company does not evaluate whether the selling price includes a financing interest component for contracts that are less than a year. The Company also expenses costs incurred to obtain a contract, primarily sales commissions, as all obligations will be settled in less than one year.
Cost of Sales	Cost of Sales — The Company includes all costs directly related to the production of goods for sale in cost of sales in the statement of operations. These costs include direct material, direct labor, production related overheads, excess and obsolescence costs, lower of cost or market provisions, freight and distribution costs, and the depreciation and amortization of assets directly used in the production of goods for sale.
Selling, General and Administrative Expenses	Selling, General and Administrative Expenses — These amounts primarily include payroll-related expenses for both administrative and selling personnel, compensation expense from stock-based awards, restructuring-related charges, third-party professional services and transactional gains or losses for foreign currency transactions, excluding the foreign exchange exposure for intercompany loan transactions, which is included in Other income, net.
Cash and Cash Equivalents	Cash and Cash Equivalents
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for current and expected credit losses — The Company carries its accounts receivable at their face amounts less an allowance for current and expected credit losses. The allowance for current and expected credit losses reflects the best estimate of current and expected
Inventories	Inventories
Property, Plant and Equipment	Property, Plant and Equipment — Property, plant and equipment, net, is recorded at cost less accumulated depreciation. Maintenance and repair expenditures are charged to expense when incurred. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets as follows: Buildings 4 to 40 years Building improvements 3 to 20 years Machinery and equipment 1 to 20 years Leasehold improvements Lesser of remaining term of the lease or useful life Software 2 to 10 years The internal and external costs incurred to develop internal use computer software during the application development stage of the implementation, including the design of the chosen path, are capitalized. Other costs, including expenses incurred during the preliminary project stage, training expenses, data conversion costs and expenses incurred in the post implementation stage are expensed in the period incurred. Capitalized costs are amortized ratably over the useful life of the software when the software becomes operational. Upgrades and enhancements to internal use software are capitalized only if the costs result in additional functionality. The Company does not plan to sell or market its internal use computer software to third parties.
Business Combinations	Business Combinations — The Company accounts for business combinations using the acquisition method of accounting, which requires that once control is obtained, all the assets acquired and liabilities assumed, including amounts attributable to noncontrolling interests, are recorded at their respective fair values at the date of acquisition. The determination of fair values of identifiable assets and liabilities requires estimates and the use of valuation techniques when market value is not readily available. For intangible assets acquired in a business combination, the Company typically use the income method. Significant estimates in valuing certain intangible assets include, but are not limited to, the amount and timing of future cash flows, growth rates, discount rates and useful lives. The excess of the purchase price over fair values of identifiable assets and liabilities is recorded as goodwill
Long-Lived Asset and Finite - Lived Intangible Asset Impairments	Long-Lived Asset and Finite - Lived Intangible Asset Impairments — The Company reviews long-lived assets, including property, plant and equipment and finite-lived intangible assets for impairment whenever events or changes in business circumstances indicate that the carrying amount of the asset may not be fully recoverable. The Company groups assets at the lowest level for which cash flows are separately identified in order to measure an impairment. Recoverability of an asset or asset group is first measured by a comparison of the carrying amount to its estimated undiscounted future cash flows expected to be generated by the asset or asset group. If the carrying amount exceeds its estimated undiscounted future cash flows, an impairment charge is recognized as the amount by which the carrying amount of the asset or asset group exceeds the estimated fair value. If impairment is determined to exist, any related impairment loss is calculated based on the estimated fair value. Impairment losses on assets to be disposed of or held for sale, if any, are based on the estimated proceeds to be received, less costs of disposal.
Goodwill and Indefinite-Lived Intangible Assets Impairments	Goodwill and Indefinite-Lived Intangible Asset Impairments — The Company assesses the recoverability of goodwill and indefinite-lived trade names on an annual basis in accordance with Accounting Standards Codification (“ASC”) 350 “Intangibles - Goodwill and Other.” The measurement date is the first day of the fourth fiscal quarter, or more frequently, if events or circumstances indicate that it is more likely than not that the fair value of a reporting unit or the respective indefinite-lived trade name is less than the carrying value. The Company can elect to perform a quantitative or qualitative test of impairment. For fiscal 2022, 2021, and 2020 the Company performed a quantitative impairment assessment for goodwill. The Company calculated the fair value of its six reporting units considering three valuation approaches: (a) the income approach; (b) the guideline public company method; and (c) the comparable transaction method. The income approach calculates the fair value of the reporting unit using a discounted cash flow approach. Internally forecasted future cash flows, which the Company believes reasonably approximate market participant assumptions, are discounted using a weighted average cost of capital (Discount Rate) developed for each reporting unit. The Discount Rate is developed using market observable inputs, as well as considering whether or not there is a measure of risk related to the specific reporting unit’s forecasted performance. The key uncertainties in these calculations are the assumptions used in determining the reporting unit’s forecasted future performance, including revenue growth and EBITDA margins, as well as the perceived risk associated with those forecasts. Fair value under the guideline public company method is determined for each reporting unit by applying market multiples for comparable public companies to the reporting unit’s financial results. Fair value under the comparable transaction method is determined based on exchange prices in actual transactions and on asking prices for controlling interests in public or private companies currently offered for sale by applying market multiples for comparable public companies to the unit’s financial results. The key uncertainties in the guideline public company method and the comparable transaction method calculations are the assumptions used in determining the reporting unit's comparable public companies, comparable transactions and the selection of the market multiples. The Company did not record any goodwill impairments in fiscal 2022, 2021, and 2020.
Fair Value Measurements	Fair Value Measurements — Authoritative guidance for fair value measurements establishes a three-level hierarchy that ranks the quality and reliability of information used in developing fair value estimates. The hierarchy gives the highest priority to quoted prices in active markets and the lowest priority to unobservable data. In cases where two or more levels of inputs are used to determine fair value, a financial instrument's level is determined based on the lowest level input that is considered significant to the fair value measurement in its entirety. The three levels of the fair value hierarchy are summarized as follows: Level 1-inputs are based upon quoted prices (unadjusted) in active markets for identical assets or liabilities which are accessible as of the measurement date. Level 2-inputs are based upon quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, and model-derived valuations for the asset or liability that are derived principally from or corroborated by market data for which the primary inputs are observable, including forward interest rates, yield curves, credit risk and exchange rates.
Income Taxes and Uncertain Tax Positions	Income Taxes and Uncertain Tax Positions — The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the consolidated financial statements. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial reporting and tax basis of assets and liabilities using enacted tax rates in effect for the year it is expected the differences will reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period of the enactment date. The Company periodically assesses the realizability of the deferred tax assets. In making this determination management considers all available evidence, both positive and negative, including earnings history, expectations of future taxable income and available tax planning strategies. A valuation allowance is recorded to reduce the Company’s deferred tax assets to the amount that is considered more likely than not to be realized. Changes in the required valuation allowance are recorded in income in the period such determination is made.
Leases	Leases The Company engages in leasing transactions to meet the needs of the business. The Company leases certain manufacturing facilities, warehouses and distribution centers, office space, forklifts, vehicles and other machinery and equipment. The determination to lease, rather than purchase, an asset is primarily contingent upon capital requirements, duration of the forecasted business investment, and asset availability. The Company determines if an arrangement is a lease at inception and all arrangements deemed to be leases are subject to an assessment to determine the classification between finance and operating leases. The Company's significant assumptions and judgments in determining whether a contract is or contains a lease include establishing whether the supplier has the ability to use other assets to fulfill its service or whether the terms of the agreement enable the Company to control the use of a dedicated property, plant and equipment asset during the contract term. In the majority of the Company's contracts where it must identify whether a lease is present, it is readily determinable that the Company controls the use of the assets and obtains substantially all of the economic benefit during the term of the contract. In those contracts where identification is not readily determinable, the Company has determined that the supplier has either the ability to use another asset to provide the service or the terms of the contract give the supplier the rights to operate the asset at its discretion during the term of the contract, in which case the arrangement would not constitute a lease. Right-of-use assets and lease obligations are recognized based on the present value of the future minimum lease payments over the lease term as of the commencement date. The Company’s lease agreements have terms that include both lease and non-lease components. Lease component fees are included in the present value of future minimum lease payments. Conversely, non-lease components are not subject to capitalization and are expensed as incurred. Per ASC 842 “Leases,” the contractual interest rate is used to calculate the present value of the future minimum lease payments. However, the majority of the Company’s leases do not provide an implicit rate. Therefore, the Company's significant assumption and judgments in determining the discount rate include determining the incremental borrowing rate. The Company’s incremental borrowing rates are based on the term of the lease, the economic environment of the lease and the effect of collateralization. The valuation of the ROU asset also includes lease payments made in advance of the lease commencement date and initial direct costs incurred to secure the lease and is reduced for lease incentives. The lease terms include options to extend or terminate the lease when it is reasonably certain the Company will exercise the options. Leases with an initial term of 12 months or less are classified as short-term leases and are not recorded on the consolidated balance sheets. The lease expense for short-term leases is recognized on a straight-line basis over the lease term. The Company has certain leasing agreements, related to leased vehicles available to our sales personnel, that contain guaranteed residual value terms, which are not expected to be triggered. The Company’s leasing portfolio does not contain any material restrictive covenants.
Translation of Foreign Currency	Translation of Foreign Currency — For the Company's non-U.S. subsidiaries that report in a functional currency other than United States dollars, assets and liabilities are translated into United States dollars using period end exchange rates. Revenue and expenses are translated at the monthly average exchange rates in effect during the reporting period. Foreign currency translation adjustments are included as a component of accumulated other comprehensive loss within the consolidated statements of comprehensive income.
Recent Accounting Pronouncements	Recent Accounting Pronouncements A summary of recently adopted Accounting Standards Update ("ASU")s are as follows. Adoption dates are on the first day of the fiscal year indicated below, unless otherwise specified. Adopted Guidance ASU Description of ASU Impact to Atkore Adoption Date 2019-12 Simplifying the accounting for income taxes (Topic 740) The ASU eliminates certain existing exceptions related to the general approach in ASC 740 relating to franchise taxes, reducing complexity in the interim period accounting for year to date loss limitations and changes in tax laws and clarifying the accounting for transactions outside of a business combination that result in a step up in the tax basis of goodwill. The Company adopted this standard in the first quarter of 2022. The adoption of the standard did not have a material impact on the Company ’ s consolidated financial statements. 2022

BASIS OF PRESENTATION AND SUM_3

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Estimated Useful Lives	Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets as follows: Buildings 4 to 40 years Building improvements 3 to 20 years Machinery and equipment 1 to 20 years Leasehold improvements Lesser of remaining term of the lease or useful life Software 2 to 10 years As of September 30, 2022 and September 30, 2021, property, plant and equipment at cost and accumulated depreciation were as follows: (in thousands) September 30, 2022 September 30, 2021 Land $ 22,113 $ 23,043 Buildings and related improvements 172,633 136,680 Machinery and equipment 427,460 372,503 Leasehold improvements 10,512 9,720 Software 36,884 28,288 Construction in progress 99,491 43,055 Property, plant and equipment, at cost 769,093 613,289 Accumulated depreciation (378,873) (337,667) Property, plant and equipment, net $ 390,220 $ 275,622
Schedule of Recent Accounting Pronouncements	A summary of recently adopted Accounting Standards Update ("ASU")s are as follows. Adoption dates are on the first day of the fiscal year indicated below, unless otherwise specified. Adopted Guidance ASU Description of ASU Impact to Atkore Adoption Date 2019-12 Simplifying the accounting for income taxes (Topic 740) The ASU eliminates certain existing exceptions related to the general approach in ASC 740 relating to franchise taxes, reducing complexity in the interim period accounting for year to date loss limitations and changes in tax laws and clarifying the accounting for transactions outside of a business combination that result in a step up in the tax basis of goodwill. The Company adopted this standard in the first quarter of 2022. The adoption of the standard did not have a material impact on the Company ’ s consolidated financial statements. 2022

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Sep. 30, 2022
Leases [Abstract]
Assets and Liabilities, Leases	(in thousands) September 30, 2022 September 30, 2021 Assets Operating lease assets $ 68,715 $ 38,569 Finance lease assets 5,209 4,966 Right-of-use assets, at cost $ 73,924 $ 43,535 Less: accumulated amortization (2,889) (2,422) Right-of-use assets, net $ 71,035 $ 41,113 Liabilities Current liabilities: Current portion of operating lease liabilities $ 12,777 $ 10,873 Current portion of finance lease liabilities 1,012 912 Current lease obligations $ 13,789 $ 11,785 Noncurrent liabilities: Operating lease liabilities $ 56,601 $ 28,434 Finance lease liabilities 1,374 1,802 Long-term lease obligations $ 57,975 $ 30,236 Total lease obligations $ 71,764 $ 42,021
Lease, Cost	The following table summarizes lease costs by type of cost for the fiscal year ended September 30, 2022, and the fiscal year ended September 30, 2021. In the consolidated statements of operations, cost of sales and selling, general and administrative expenses included lease costs of $15,583 and $3,732 for the fiscal year ended September 30, 2022 and $14,536 and $2,781 for the fiscal year end September 30, 2021. Fiscal year ended (in thousands) September 30, 2022 September 30, 2021 Amortization of right-of-use assets $ 13,916 $ 14,515 Interest on lease liabilities 71 49 Variable lease costs 2,471 938 Short term lease costs 2,857 1,815 Total lease costs $ 19,315 $ 17,317 Lease Term and Discount Rate Fiscal year ended September 30, 2022 September 30, 2021 Weighted-average remaining lease term (years) Operating leases 8.1 5.2 Finance leases 2.7 3.3 Weighted-average discount rate Operating leases 4.5 % 4.0 % Finance leases 3.0 % 2.5 %
Operating Lease, Liability, Maturity	The Company's maturity analysis of its lease liabilities as of September 30, 2022 is as follows: (in thousands) Financing Leases Operating Leases 2023 $ 1,068 $ 15,259 2024 796 13,651 2025 443 11,023 2026 241 9,416 2027 23 7,769 2028 and after — 19,277 Total lease payments $ 2,571 $ 76,395 Less: Interest (185) (7,017) Present value of lease liabilities $ 2,386 $ 69,378
Finance Lease, Liability, Maturity	The Company's maturity analysis of its lease liabilities as of September 30, 2022 is as follows: (in thousands) Financing Leases Operating Leases 2023 $ 1,068 $ 15,259 2024 796 13,651 2025 443 11,023 2026 241 9,416 2027 23 7,769 2028 and after — 19,277 Total lease payments $ 2,571 $ 76,395 Less: Interest (185) (7,017) Present value of lease liabilities $ 2,386 $ 69,378

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	12 Months Ended
	Sep. 30, 2022
Business Combination and Asset Acquisition [Abstract]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table summarizes the Level 3 fair values assigned to the net assets acquired and liabilities assumed as of the acquisition date for fiscal 2022: (in thousands) United Poly Other Total Fair value of consideration transferred: Cash consideration $ 227,234 $ 93,044 $ 320,278 Purchase price payable — 12,628 12,628 Working Capital Adjustment — — — Total consideration transferred $ 227,234 $ 105,672 $ 332,906 Fair value of assets acquired and liabilities assumed: Cash 11,639 126 11,765 Accounts receivable 23,679 9,291 32,970 Inventories 13,455 8,111 21,566 Intangible assets 128,840 54,330 183,170 Fixed assets 13,648 8,533 22,181 Accounts payable (11,940) (5,086) (17,026) Income taxes (15,542) (2,075) (17,617) Other (1,742) 244 (1,498) Net assets acquired 162,037 73,474 235,511 Excess purchase price attributed to goodwill acquired $ 65,197 $ 32,198 $ 97,395 (in thousands) FRE Composites Fair value of consideration transferred: Cash consideration $ 36,993 Fair value of assets acquired and liabilities assumed: Cash 437 Accounts receivable 2,163 Inventories 3,355 Intangible assets 18,300 Fixed assets 8,509 Accounts payable (1,186) Income Taxes (4,293) Other (240) Net assets acquired 27,045 Excess purchase price attributed to goodwill acquired $ 9,948
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination	The following table summarizes the fair value of intangible assets as of the acquisition date: United Poly Other (in thousands) Fair Value Weighted Average Useful Life (Years) Fair Value Weighted Average Useful Life (Years) Customer relationships $ 111,700 11 $ 50,020 9 Other 17,140 8 4,310 8 Total intangible assets $ 128,840 $ 54,330 The following table summarizes the fair value of intangible assets as of the acquisition date: FRE Composites ($ in thousands) Fair Value Weighted Average Useful Life (Years) Customer relationships $ 14,700 12.0 Other 3,600 6.0 Total intangible assets $ 18,300
Schedule of Business Acquisition, Pro Forma Results of Operations	The following table presents unaudited pro forma results of operations for the Company and all companies acquired in fiscal 2022 as if those acquisitions had occurred on October 1, 2020. The results presented below are for the fiscal years ended: Fiscal year ended (in thousands) September 30, 2022 September 30, 2021 Pro forma net sales $ 4,060,993 $ 3,048,378 Pro forma net income 920,022 584,754

POSTRETIREMENT BENEFITS (Tables

POSTRETIREMENT BENEFITS (Tables)	12 Months Ended
	Sep. 30, 2022
Retirement Benefits [Abstract]
Schedule of Benefit Cost	The net periodic cost for the periods presented was as follows: Fiscal Year Ended (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Interest cost 2,958 2,729 3,739 Expected return on plan assets (5,392) (6,424) (6,331) Amortization of actuarial loss 631 1,327 888 Net periodic cost $ (1,803) $ (2,368) $ (1,704) The weighted-average assumptions used to determine net periodic pension cost during the period were as follow: September 30, 2022 September 30, 2021 September 30, 2020 Discount rate 2.7 % 2.5 % 3.1 % Expected return on plan assets 4.0 % 6.2 % 6.3 % Rate of compensation increase N/a N/a N/a
Schedule of Change in Benefit Obligations and Plan Assets	The change in the benefit obligations, plan assets and the amounts recognized on the consolidated balance sheets was as follows (in thousands): Change in benefit obligations: Balance as of September 30, 2020 $ 146,759 Interest cost 2,729 Actuarial loss (3,170) Benefits and administrative expenses paid (5,573) Balance as of September 30, 2021 140,745 Interest cost 2,958 Actuarial gain (36,411) Benefits and administrative expenses paid (6,090) Balance as of September 30, 2022 $ 101,202 Change in plan assets: Balance as of September 30, 2020 106,736 Actual return on plan assets 17,258 Employer contributions 19,635 Benefits and administrative expenses paid (5,573) Balance as of September 30, 2021 138,056 Actual return on plan assets (28,230) Employer contributions 188 Benefits and administrative expenses paid (6,090) Balance as of September 30, 2022 $ 103,925 Funded status: Funded status as of September 30, 2021 $ (2,689) Funded status as of September 30, 2022 $ 2,723
Schedule of Amounts Recognized in Balance Sheet	(in thousands) September 30, 2022 September 30, 2021 Amounts recognized in the consolidated balance sheets consist of: Pension Non-Current Assets $ 2,723 $ 1,130 Pension liabilities $ — $ (3,819) Net amount recognized $ 2,723 $ (2,689) Amounts recognized in accumulated other comprehensive loss (before income taxes) consist of: Net actuarial loss $ (23,616) $ (27,036) Total loss recognized $ (23,616) $ (27,036) Weighted-average assumptions used to determine pension benefit obligations at year end: Discount rate 5.4 % 2.7 % Rate of compensation increase N/a N/a
Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets	The following table summarizes the defined benefit pension plans with accumulated benefit obligations in excess of plan assets: (in thousands) September 30, 2022 September 30, 2021 Accumulated benefit obligation $ — $ 122,655 Fair value of plan assets — 118,843 The following table summarizes the defined benefit pension plans with projected benefit obligations in excess of plan assets: (in thousands) September 30, 2022 September 30, 2021 Projected benefit obligation $ — $ 122,655 Fair value of plan assets — 118,843
Schedule of Allocation of Plan Assets	Pension plans have the following weighted-average asset allocations: Asset Category: September 30, 2022 September 30, 2021 Equity securities 50% 56% Debt securities 46% 43% Cash and cash equivalents 4% 1% Total 100% 100% September 30, 2022 September 30, 2021 (in thousands) Level 1 Level 2 Total Level 1 Level 2 Total United States equity securities $ 29,583 $ — $ 29,583 $ 48,274 $ — $ 48,274 Non-U.S. equity securities 22,913 — 22,913 28,787 — 28,787 Fixed income securities 22,639 24,794 47,433 59,488 — 59,488 Cash and cash equivalents 3,996 — 3,996 1,507 — 1,507 Total $ 79,131 $ 24,794 $ 103,925 $ 138,056 $ — $ 138,056
Schedule of Future Benefit Payments	Benefit payments, which reflect future expected service as appropriate, are expected to be paid in each fiscal year as follows: (in thousands) 2023 $ 6,693 2024 6,893 2025 7,101 2026 7,294 2027 7,390 2028 to 2032 37,238

STOCK INCENTIVE PLAN (Tables)

STOCK INCENTIVE PLAN (Tables)	12 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Schedule of Assumptions	The assumptions used in the Black-Scholes option pricing model to value the options granted were as follows: Fiscal Year Ended September 30, 2022 September 30, 2021 September 30, 2020 Expected dividend yield — % — % — % Expected volatility 49 % 59 % 36 % Range of risk-free interest rates 1.40 % 0.52 % 1.67% Range of expected option lives 6 years 6 years 6 years September 30, 2022 September 30, 2021 September 30, 2020 Expected dividend yield — % — % — % Expected volatility 63 % 61 % 21% - 53% Risk free interest rates 0.83 % 0.21 % 1.59 % Expected life 3 years 3 years 3 years Fair value $122.25 $33.80 $44.22
Schedule of Stock Option Activity	Stock option activity for the period September 30, 2019 to September 30, 2022 was as follows: Shares Weighted-Average Exercise Price Weighted-Average Grant Date Fair Value Aggregate Intrinsic Value Weighted-Average Remaining Contractual Term (in years) Outstanding as of September 30, 2019 1,836 12.94 $ 31,957 Granted 67 37.24 Exercised (508) 8.55 $ 14,548 Forfeited (20) 19.13 Outstanding as of September 30, 2020 1,375 15.66 $ 11,443 Granted 72 29.80 Exercised (678) 12.30 $ 33,075 Forfeited — — Outstanding as of September 30, 2021 769 19.95 $ 10.89 $ 51,441 Granted 42 105.94 $ 49.39 Exercised (98) 12.58 $ 9.84 $ 8,703 Forfeited — — Outstanding as of September 30, 2022 713 26.00 $ 13.29 38,062 5.22 Exercisable as of September 30, 2022 505 $ 18.56 $ 29,938 4.38
Schedule of Nonvested Share Activity	Changes to the Company’s nonvested RSU awards for the year ended September 30, 2022 were as follows: Shares Weighted-average grant-date fair value Nonvested as of September 30, 2019 674 $ 19.37 Granted 166 37.24 Vested (403) 19.43 Forfeited (32) 22.29 Nonvested as of September 30, 2020 405 26.44 Granted 218 32.01 Vested (229) 23.78 Forfeited (10) 28.48 Nonvested as of September 30, 2021 384 30.30 Granted 100 103.94 Vested (208) 27.40 Forfeited (14) 49.23 Nonvested as of September 30, 2022 262 $ 58.72 Changes to the Company’s non-vested PSU awards for the year ended September 30, 2022 were as follows: Shares Weighted-average grant-date fair value Nonvested as of September 30, 2019 455 $ 21.11 Granted 115 40.43 Vested (162) 25.21 Adjustment for achieved performance upon issuance 31 21.68 Forfeited (14) 22.82 Nonvested as of September 30, 2020 425 $ 25.15 Granted 156 31.67 Vested (171) 21.55 Adjustment for achieved performance upon issuance 57 22.95 Forfeited (14) 29.43 Nonvested as of September 30, 2021 453 $ 28.07 Granted 52 113.51 Vested (381) 18.17 Adjustment for achieved performance upon issuance 190 18.17 Forfeited (1) 57.61 Nonvested as of September 30, 2022 313 $ 48.19

OTHER INCOME, NET (Tables)

OTHER INCOME, NET (Tables)	12 Months Ended
	Sep. 30, 2022
Other Income, Nonoperating [Abstract]
Schedule of Other Expense, Net	Other income, net consisted of the following: Fiscal Year Ended (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Gain on purchase of business $ — $ (731) $ — Undesignated foreign currency derivative instruments (4,379) 2,201 1,269 Business interruption insurance recovery — (15,500) — Foreign exchange loss (gain) on intercompany loans 5,342 (1,534) (2,342) Pension-related benefits (1,803) (2,368) (1,704) Other 350 (220) — Other income, net $ (490) $ (18,152) $ (2,777)

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Sep. 30, 2022
Income Tax Disclosure [Abstract]
Schedule of Components of Income (Loss) from Continuing Operations and Income Tax Expense	Significant components of income before income taxes and income tax expense for the fiscal years ended September 30, 2022, September 30, 2021 and September 30, 2020 consisted of the following: (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Components of income before income taxes: United States $ 1,174,109 $ 770,350 $ 201,784 Non-U.S 29,511 9,651 214 Income before income taxes $ 1,203,620 $ 780,001 $ 201,998 Income tax expense: Current: United States: Federal $ 228,141 $ 182,105 $ 32,335 State 49,793 46,913 9,668 Non-U.S: 9,198 6,432 3,210 Current income tax expense $ 287,132 $ 235,450 $ 45,213 Deferred: United States: Federal $ 3,174 $ (35,442) $ 5,102 State 753 (7,281) 49 Non-U.S: (873) (583) (668) Deferred income (benefit) tax expense 3,054 (43,306) 4,483 Income tax expense $ 290,186 $ 192,144 $ 49,696
Schedule of Federal Income Tax Rate and Effective Income Tax Rate Reconciliation	Differences between the statutory federal income tax rate and effective income tax rate are summarized below: (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Statutory federal tax 21 % 21 % 21 % Adjustments to reconcile to the effective income tax rate: State income taxes 3 % 4 % 4 % Stock-based compensation (1) % (1) % (2) % Other 1 % 1 % 2 % Effective income tax rate 24 % 25 % 25 %
Schedule of Components of Net Deferred Income Tax Assets	The components of the net deferred income tax assets are as follows: (in thousands) September 30, 2022 September 30, 2021 Deferred tax assets: Accrued liabilities and reserves $ 47,582 $ 42,932 Tax loss and credit carryforwards 17,272 16,096 Postretirement benefits 583 2,057 Inventory 29,501 36,021 Lease obligations 17,779 10,616 Other 1,079 633 $ 113,796 $ 108,355 Deferred tax liabilities: Property, plant and equipment $ (28,475) $ (21,784) Intangible assets (56,886) (43,657) Loss on investment — (5,102) Right-of-use assets, net (17,095) (10,247) Other (4,156) (3,095) $ (106,612) $ (83,885) Net deferred tax liability before valuation allowance 7,184 24,470 Valuation allowance (13,415) (11,523) Net deferred tax liability $ (6,231) $ 12,947
Schedule of Reconciliation of Unrecognized Tax Benefits, Excluding Interest and Penalties	A reconciliation of the beginning and ending amount of unrecognized tax benefit, excluding interest and penalties, is as follows: (in thousands) For the period from September 30, 2019 to September 30, 2022 Balance as of September 30, 2019 $ 794 Additions based on tax positions related to prior years 925 Additions based on tax positions related to current year 122 Settlements (227) Balance as of September 30, 2020 1,614 Additions based on tax positions related to prior years 291 Additions based on tax positions related to current year 1,658 Settlements (230) Balance as of September 30, 2021 3,333 Additions based on tax positions related to prior years 322 Additions based on tax positions related to current year 342 Settlements (3,012) Balance as of September 30, 2022 $ 985
Schedule of Tax Years Subject to Examination	The following tax years remain subject to examination by the major tax jurisdictions as follows: Jurisdiction Years Open to Audit United States 2019, 2020 and 2021

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Sep. 30, 2022
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Earnings Per Share	The following table sets forth the computation of basic and diluted earnings per share: Fiscal Year Ended (in thousands, except per share data) September 30, 2022 September 30, 2021 September 30, 2020 Numerator: Net income $ 913,434 $ 587,857 $ 152,302 Less: Undistributed earnings allocated to participating securities 14,460 11,380 3,356 Net income available to common shareholders $ 898,974 $ 576,477 $ 148,946 Denominator: Basic weighted average common shares outstanding 43,717 46,569 47,265 Effect of dilutive securities: Non-participating employee stock options (1) 563 737 779 Diluted weighted average common shares outstanding 44,280 47,306 48,044 Basic earnings per share $ 20.56 $ 12.38 $ 3.15 Diluted earnings per share $ 20.30 $ 12.19 $ 3.10 (1) Stock options to purchase approximately 0.0 million , 0.0 million, and 0.3 million shares of common stock were outstanding during the years ended September 30, 2022, September 30, 2021, and September 30, 2020, respectively, but were not included in the calculation of diluted earnings per share as the impact of these would have been anti-dilutive.

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE LOSS (Tables)	12 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Loss	The following table presents the changes in accumulated other comprehensive loss by component, net of tax: (in thousands) Defined benefit pension items Currency translation adjustments Total Balance as of September 30, 2020 $ (30,761) $ (11,793) $ (42,554) Other comprehensive (loss) income before reclassifications 10,453 2,385 12,838 Amounts reclassified from accumulated other comprehensive loss 990 — 990 Net current period other comprehensive (loss) income 11,443 2,385 13,828 Balance as of September 30, 2021 $ (19,318) $ (9,408) $ (28,726) Other comprehensive income (loss) before reclassifications 2,051 (23,943) (21,892) Amounts reclassified from accumulated other comprehensive loss 472 — 472 Net current period other comprehensive income (loss) 2,523 (23,943) (21,420) Balance as of September 30, 2022 $ (16,795) $ (33,351) $ (50,146)
Reclassification out of Accumulated Other Comprehensive Income	The following is a summary of the amounts reclassified from accumulated other comprehensive loss to net income: Fiscal Year Ended (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Amortization of defined benefit pension items: Amortization of net loss (included within other income, net) $ 631 $ 1,327 $ 888 Tax expense (159) (337) (227) Net reclassifications for the period $ 472 $ 990 $ 661

INVENTORIES, NET (Tables)

INVENTORIES, NET (Tables)	12 Months Ended
	Sep. 30, 2022
Inventory Disclosure [Abstract]
Schedule of Inventory, Net	(in thousands) September 30, 2022 September 30, 2021 Purchased materials and manufactured parts, net $ 166,038 $ 105,460 Work in process, net 61,182 35,043 Finished goods, net 227,291 145,486 Inventories, net $ 454,511 $ 285,989

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	12 Months Ended
	Sep. 30, 2022
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets as follows: Buildings 4 to 40 years Building improvements 3 to 20 years Machinery and equipment 1 to 20 years Leasehold improvements Lesser of remaining term of the lease or useful life Software 2 to 10 years As of September 30, 2022 and September 30, 2021, property, plant and equipment at cost and accumulated depreciation were as follows: (in thousands) September 30, 2022 September 30, 2021 Land $ 22,113 $ 23,043 Buildings and related improvements 172,633 136,680 Machinery and equipment 427,460 372,503 Leasehold improvements 10,512 9,720 Software 36,884 28,288 Construction in progress 99,491 43,055 Property, plant and equipment, at cost 769,093 613,289 Accumulated depreciation (378,873) (337,667) Property, plant and equipment, net $ 390,220 $ 275,622

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	12 Months Ended
	Sep. 30, 2022
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	Changes in the carrying amount of goodwill are as follows: Segment (in thousands) Electrical Safety & Infrastructure Total Balance as of September 30, 2020 $ 144,662 $ 43,577 $ 188,239 Goodwill acquired during year 9,948 — 9,948 Exchange rate effects 861 — 861 Balance as of September 30, 2021 $ 155,471 $ 43,577 $ 199,048 Goodwill acquired during year 87,964 9,431 97,395 Exchange rate effects (6,727) (386) (7,113) Balance as of September 30, 2022 $ 236,708 $ 52,622 $ 289,330
Schedule of Finite-Lived Intangible Assets	The following table provides the gross carrying value, accumulated amortization, and net carrying value for each major class of intangible assets: September 30, 2022 September 30, 2021 (in thousands) Weighted Average Useful Life (Years) Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value Amortizable Intangible Assets: Customer relationships 11 $ 532,768 $ (267,940) $ 264,828 $ 371,048 $ (234,946) $ 136,102 Other 8 35,681 (10,602) 25,079 23,633 (11,411) 12,222 Total 568,449 (278,542) 289,907 394,681 (246,357) 148,324 Indefinite-lived Intangible Assets: Trade names 92,799 — 92,799 92,880 — 92,880 Total $ 661,248 $ (278,542) $ 382,706 $ 487,561 $ (246,357) $ 241,204
Schedule of Indefinite-Lived Intangible Assets	The following table provides the gross carrying value, accumulated amortization, and net carrying value for each major class of intangible assets: September 30, 2022 September 30, 2021 (in thousands) Weighted Average Useful Life (Years) Gross Carrying Value Accumulated Amortization Net Carrying Value Gross Carrying Value Accumulated Amortization Net Carrying Value Amortizable Intangible Assets: Customer relationships 11 $ 532,768 $ (267,940) $ 264,828 $ 371,048 $ (234,946) $ 136,102 Other 8 35,681 (10,602) 25,079 23,633 (11,411) 12,222 Total 568,449 (278,542) 289,907 394,681 (246,357) 148,324 Indefinite-lived Intangible Assets: Trade names 92,799 — 92,799 92,880 — 92,880 Total $ 661,248 $ (278,542) $ 382,706 $ 487,561 $ (246,357) $ 241,204
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	Expected amortization expense for intangible assets over the next five years and thereafter is as follows (in thousands): 2023 $ 50,650 2024 47,457 2025 36,938 2026 32,515 2027 30,537 2028 and thereafter 91,810

DEBT (Tables)

DEBT (Tables)	12 Months Ended
	Sep. 30, 2022
Debt Disclosure [Abstract]
Schedule of Debt	Debt as of September 30, 2022 and September 30, 2021 was as follows: (in thousands) September 30, 2022 September 30, 2021 New Senior Secured Term Loan Facility due May 26, 2028 $ 371,381 $ 371,095 Senior Notes Due June 1, 2031 400,000 400,000 ABL Credit Facility — — Deferred financing costs (10,844) (12,709) Long-term debt $ 760,537 $ 758,386
Schedule of Contractual Obligation, Fiscal Year Maturity	As of September 30, 2022, future contractual maturities of long-term debt are as follows (in thousands): 2023 $ — 2024 — 2025 — 2026 — 2027 — 2028 and thereafter $ 773,000

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value	The following table presents the recurring assets and liabilities measured at fair value as of September 30, 2022 and September 30, 2021 in accordance with the fair value hierarchy: September 30, 2022 September 30, 2021 (in thousands) Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Assets Cash equivalents $ 291,757 $ — $ — $ 489,987 $ — $ — Forward currency contracts — — — — 127 — Liabilities Forward currency contracts — $ — — — $ 183 —
Estimated Fair Value of Financial Instruments Not Carried at Fair Value	The estimated fair value of financial instruments not carried at fair value in the consolidated balance sheets were as follows: September 30, 2022 September 30, 2021 (in thousands) Carrying Value Fair Value Carrying Value Fair Value New Senior Secured Term Loan Facility due May 26, 2028 $ 373,000 $ 370,203 $ 373,000 $ 371,486 Senior Notes due June 2031 400,000 318,912 400,000 415,828 Total debt $ 773,000 $ 689,115 $ 773,000 $ 787,314

SEGMENT INFORMATION (Tables)

SEGMENT INFORMATION (Tables)	12 Months Ended
	Sep. 30, 2022
Segment Reporting [Abstract]
Schedule of Segment Information	Fiscal year ended September 30, 2022 September 30, 2021 September 30, 2020 (in thousands) External Net Sales Inter- segment Sales Adjusted EBITDA External Net Sales Inter- segment Sales Adjusted EBITDA External Net Sales Inter- segment Sales Adjusted EBITDA Electrical $ 3,013,755 $ — $ 1,273,410 $ 2,229,862 $ 3,437 $ 873,868 $ 1,267,988 $ 2,559 $ 292,809 Safety & Infrastructure 900,194 394 $ 138,390 698,152 168 $ 81,827 497,433 90 $ 67,821 Eliminations (394) — (3,605) — (2,649) Consolidated operations $ 3,913,949 $ — $ 2,928,014 $ — $ 1,765,421 $ — Capital Expenditures Total Assets (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 September 30, 2022 September 30, 2021 September 30, 2020 Electrical $ 61,721 $ 34,995 $ 16,067 $ 1,524,670 $ 1,122,835 $ 794,931 Safety & Infrastructure 38,280 22,407 15,470 618,331 482,942 255,903 Unallocated 35,775 7,072 2,233 455,995 604,322 507,691 Consolidated operations $ 135,776 $ 64,474 $ 33,770 $ 2,598,996 $ 2,210,099 $ 1,558,525 Presented below is a reconciliation of operating segment Adjusted EBITDA to Income before income taxes: Fiscal Year Ended (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Operating segment Adjusted EBITDA Electrical $ 1,273,410 $ 873,868 $ 292,809 Safety & Infrastructure 138,390 81,827 67,821 Total $ 1,411,800 $ 955,695 $ 360,630 Unallocated expenses (a) (70,010) (58,148) (33,995) Depreciation and amortization (84,415) (78,557) (74,470) Interest expense, net (30,676) (32,899) (40,062) Loss on extinguishment of debt — (4,202) (273) Stock-based compensation (17,245) (17,047) (13,064) Transaction costs (3,424) (667) (196) Other (b) (2,410) 15,826 3,428 Income before income taxes $ 1,203,620 $ 780,001 $ 201,998 (a) Represents unallocated selling, general and administrative activities and associated expenses including, in part, executive, legal, finance, human resources, information technology, business development and communications, as well as certain costs and earnings of employee-related benefits plans, such as stock-based compensation and a portion of self-insured medical costs. (b) Represents other items, such as inventory reserves and adjustments, loss on disposal of property, plant and equipment, insurance recovery related to damages of property, plant and equipment, release of indemnified uncertain tax positions and realized or unrealized gain (loss) on foreign currency impacts of intercompany loans, restructuring charges, gain on purchase of business, impairment charges, and related forward currency derivatives. The Company’s long-lived assets and net sales by geography were as follows: Long-lived assets Net sales (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 September 30, 2022 September 30, 2021 September 30, 2020 United States $ 410,263 $ 258,069 $ 203,694 $ 3,552,893 $ 2,637,118 $ 1,563,258 Other Americas 7,195 6,180 146 102,626 53,151 26,421 Europe 38,396 45,917 41,283 213,581 183,985 132,299 Asia-Pacific 5,400 6,569 1,759 44,849 53,760 43,443 Total $ 461,255 $ 316,735 $ 246,882 $ 3,913,949 $ 2,928,014 $ 1,765,421 The table below shows the amount of net sales from external customers for each of the Company’s product categories which accounted for 10% or more of consolidated net sales in any of the last three fiscal years: Fiscal Year Ended (in thousands) September 30, 2022 September 30, 2021 September 30, 2020 Metal Electrical Conduit and Fittings $ 635,481 $ 612,137 $ 484,476 Plastic Pipe and Conduit 1,479,331 893,199 308,561 Electrical Cable and Flexible Conduit 535,194 424,411 322,888 Other Electrical products 363,749 300,115 152,063 Electrical 3,013,755 2,229,862 1,267,988 Mechanical Pipe 445,453 395,289 244,902 Other Safety & Infrastructure products 454,741 302,863 252,531 Safety & Infrastructure 900,194 698,152 497,433 Net sales $ 3,913,949 $ 2,928,014 $ 1,765,421

BASIS OF PRESENTATION AND SUM_4

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Share Repurchase Program (Details)	Nov. 11, 2022 USD ($)	Sep. 30, 2022 USD ($) vote	Apr. 26, 2022 USD ($)	Nov. 16, 2021 USD ($)	Sep. 30, 2021 USD ($)	Jan. 28, 2021 USD ($)	Dec. 25, 2020 USD ($)	Feb. 05, 2019 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of vote per share, common stock | vote		1
Stock repurchase program, authorized amount			$ 800,000,000	$ 400,000,000		$ 100,000,000		$ 50,000,000
Remaining authorized repurchase amount		$ 300,000,000			$ 0		$ 0
Subsequent Event [Line Items]
Stock repurchase program, authorized amount			$ 800,000,000	$ 400,000,000		$ 100,000,000		$ 50,000,000
Subsequent Event
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Stock repurchase program, authorized amount	$ 1,300,000,000
Subsequent Event [Line Items]
Stock repurchase program, authorized amount	$ 1,300,000,000

BASIS OF PRESENTATION AND SUM_5

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition (Details)	12 Months Ended
	Sep. 30, 2022
Minimum
Disaggregation of Revenue [Line Items]
Performance obligation and payment period	30 days
Maximum
Disaggregation of Revenue [Line Items]
Performance obligation and payment period	60 days

BASIS OF PRESENTATION AND SUM_6

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Property, Plant and Equipment (Details)	12 Months Ended
	Sep. 30, 2022
Minimum | Buildings
Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	4 years
Minimum | Building improvements
Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	3 years
Minimum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	1 year
Minimum | Software
Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	2 years
Maximum | Buildings
Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	40 years
Maximum | Building improvements
Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	20 years
Maximum | Machinery and equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	20 years
Maximum | Software
Property, Plant and Equipment [Line Items]
Estimated useful lives (years)	10 years

BASIS OF PRESENTATION AND SUM_7

BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Goodwill and Indefinite-Lived Intangible Asset Impairments (Details)	12 Months Ended
	Sep. 30, 2022 USD ($) reportingUnit	Sep. 30, 2021 USD ($) reportingUnit	Sep. 30, 2020 USD ($) reportingUnit
Finite-Lived Intangible Assets [Line Items]
Number of reporting units | reportingUnit	6	6	6
Goodwill impairment	$ 0	$ 0	$ 0
Impairment indefinite-lived asset	$ 0	$ 0	$ 0
Customer relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	6 years
Customer relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	14 years
Other | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	1 year
Other | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life (years)	20 years

LEASES - Assets and Liabilities

LEASES - Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Assets
Operating lease assets	$ 68,715	$ 38,569
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Right-of-use assets, net	Right-of-use assets, net
Finance lease assets	$ 5,209	$ 4,966
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Right-of-use assets, net	Right-of-use assets, net
Right-of-use assets, at cost	$ 73,924	$ 43,535
Less: accumulated amortization	(2,889)	(2,422)
Right-of-use assets, net	71,035	41,113
Current liabilities:
Current portion of operating lease liabilities	$ 12,777	$ 10,873
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Current lease obligations	Current lease obligations
Current portion of finance lease liabilities	$ 1,012	$ 912
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Current lease obligations	Current lease obligations
Current lease obligations	$ 13,789	$ 11,785
Noncurrent liabilities:
Operating lease liabilities	$ 56,601	$ 28,434
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Long-term lease obligations	Long-term lease obligations
Finance lease liabilities	$ 1,374	$ 1,802
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-term lease obligations	Long-term lease obligations
Long-term lease obligations	$ 57,975	$ 30,236
Total lease obligations	$ 71,764	$ 42,021

LEASES - Additional Information

LEASES - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease, cost	$ 19,315	$ 17,317
Cost of sales
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease, cost	15,583	14,536
Selling, General and Administrative Expenses
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease, cost	$ 3,732	$ 2,781

LEASES - Lease Cost (Details)

LEASES - Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Interest on lease liabilities	$ 71	$ 49
Variable lease costs	2,471	938
Short term lease costs	2,857	1,815
Total lease costs	19,315	17,317
Amortization of right-of-use assets	$ 13,916	$ 14,515	$ 14,803

LEASES - Maturity of Lease Liab

LEASES - Maturity of Lease Liabilities (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Financing Leases
2023	$ 1,068
2024	796
2025	443
2026	241
2027	23
2028 and after	0
Total lease payments	2,571
Less: Interest	(185)
Present value of lease liabilities	2,386
Operating Leases
2023	15,259
2024	13,651
2025	11,023
2026	9,416
2027	7,769
2028 and after	19,277
Total lease payments	76,395
Less: Interest	(7,017)
Present value of lease liabilities	$ 69,378

LEASES - Lease Term and Discoun

LEASES - Lease Term and Discount Rate (Details)	Sep. 30, 2022	Sep. 30, 2021
Weighted-average remaining lease term (years)
Operating leases	8 years 1 month 6 days	5 years 2 months 12 days
Finance leases	2 years 8 months 12 days	3 years 3 months 18 days
Weighted-average discount rate
Operating leases	4.50%	4%
Finance leases	3%	2.50%

ACQUISITIONS - Narrative (Detai

ACQUISITIONS - Narrative (Details) $ in Thousands								12 Months Ended
	Aug. 31, 2022 USD ($) acquiree	Jun. 22, 2022 USD ($)	May 19, 2022 USD ($)	Dec. 21, 2021 USD ($)	Dec. 20, 2021 USD ($)	Feb. 24, 2021 USD ($)	Oct. 22, 2020 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)
Business Acquisition [Line Items]
Purchase price payable								$ 12,628	$ 0	$ 0
Business acquisition, goodwill deductible for tax purposes								31,100
Selling, General and Administrative Expenses
Business Acquisition [Line Items]
Acquisition-related expenses								3,424	$ 667
Cascade and Northwest Polymers
Business Acquisition [Line Items]
Business combination, number of acquiree | acquiree	2
Cash consideration, net of cash acquired	$ 62,100
Cash consideration	52,738
Purchase price payable	$ 9,362
Business acquisition, goodwill deductible for tax purposes								19,400
United Poly Systems, LLC
Business Acquisition [Line Items]
Cash consideration, net of cash acquired		$ 227,234
Cash consideration		227,234
Purchase price payable		$ 0
Business acquisition, goodwill deductible for tax purposes								$ 11,700
Talon Products, LLC
Business Acquisition [Line Items]
Cash consideration, net of cash acquired			$ 4,193
Purchase price payable			$ 402
Four Star Industries LLC
Business Acquisition [Line Items]
Cash consideration, net of cash acquired				$ 23,195
Sasco Tubes & Roll Forming Inc
Business Acquisition [Line Items]
Cash consideration, net of cash acquired					$ 16,184
Cash consideration					13,320
Purchase price payable					$ 2,864
FRE Composites
Business Acquisition [Line Items]
Cash consideration, net of cash acquired						$ 36,993
Goodwill recognized						$ 1,600
Queen City Plastics
Business Acquisition [Line Items]
Cash consideration, net of cash acquired							$ 6,214

ACQUISITIONS - Summary of Level

ACQUISITIONS - Summary of Level 3 Fair Values Assigned to Net Assets Acquired and Liabilities Assumed As of Acquisition Date (Details) - USD ($) $ in Thousands			12 Months Ended
	Jun. 22, 2022	Feb. 24, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Fair value of consideration transferred:
Purchase price payable			$ 12,628	$ 0	$ 0
Fair value of assets acquired and liabilities assumed:
Excess purchase price attributed to goodwill acquired			289,330	$ 199,048	$ 188,239
Fiscal 2022 Acquisitions
Fair value of consideration transferred:
Cash consideration			320,278
Purchase price payable			12,628
Working Capital Adjustment			0
Total consideration transferred			332,906
Fair value of assets acquired and liabilities assumed:
Cash			11,765
Accounts receivable			32,970
Inventories			21,566
Intangible assets			183,170
Fixed assets			22,181
Accounts payable			(17,026)
Income Taxes			(17,617)
Other			(1,498)
Net assets acquired			235,511
Excess purchase price attributed to goodwill acquired			97,395
United Poly
Fair value of consideration transferred:
Cash consideration	$ 227,234
Purchase price payable	0
Working Capital Adjustment	0
Total consideration transferred	227,234
Fair value of assets acquired and liabilities assumed:
Cash	11,639
Accounts receivable	23,679
Inventories	13,455
Intangible assets	128,840
Fixed assets	13,648
Accounts payable	(11,940)
Income Taxes	(15,542)
Other	(1,742)
Net assets acquired	162,037
Excess purchase price attributed to goodwill acquired	65,197
Other
Fair value of consideration transferred:
Cash consideration			93,044
Purchase price payable			12,628
Working Capital Adjustment			0
Total consideration transferred			105,672
Fair value of assets acquired and liabilities assumed:
Cash			126
Accounts receivable			9,291
Inventories			8,111
Intangible assets	$ 54,330		54,330
Fixed assets			8,533
Accounts payable			(5,086)
Income Taxes			(2,075)
Other			244
Net assets acquired			73,474
Excess purchase price attributed to goodwill acquired			$ 32,198
FRE Composites
Fair value of consideration transferred:
Total consideration transferred		$ 36,993
Fair value of assets acquired and liabilities assumed:
Cash		437
Accounts receivable		2,163
Inventories		3,355
Intangible assets		18,300
Fixed assets		8,509
Accounts payable		(1,186)
Income Taxes		(4,293)
Other		(240)
Net assets acquired		27,045
Excess purchase price attributed to goodwill acquired		$ 9,948

ACQUISITIONS - Summary of Fair

ACQUISITIONS - Summary of Fair Value as of Acquisition Date (Details) - USD ($) $ in Thousands	Jun. 22, 2022	Feb. 24, 2021	Sep. 30, 2022
United Poly
Business Acquisition [Line Items]
Intangible assets	$ 128,840
United Poly | Customer relationships
Business Acquisition [Line Items]
Intangible assets	$ 111,700
Weighted Average Useful Life (Years)	11 years
United Poly | Other
Business Acquisition [Line Items]
Intangible assets	$ 17,140
Weighted Average Useful Life (Years)	8 years
Other
Business Acquisition [Line Items]
Intangible assets	$ 54,330		$ 54,330
Other | Customer relationships
Business Acquisition [Line Items]
Intangible assets	$ 50,020
Weighted Average Useful Life (Years)	9 years
Other | Other
Business Acquisition [Line Items]
Intangible assets	$ 4,310
Weighted Average Useful Life (Years)	8 years
FRE Composites
Business Acquisition [Line Items]
Intangible assets		$ 18,300
FRE Composites | Customer relationships
Business Acquisition [Line Items]
Intangible assets		$ 14,700
Weighted Average Useful Life (Years)		12 years
FRE Composites | Other
Business Acquisition [Line Items]
Intangible assets		$ 3,600
Weighted Average Useful Life (Years)		6 years

ACQUISITIONS - Pro Forma Result

ACQUISITIONS - Pro Forma Results (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Business Combination and Asset Acquisition [Abstract]
Pro forma net sales	$ 4,060,993	$ 3,048,378
Pro forma net income	$ 920,022	$ 584,754

POSTRETIREMENT BENEFITS - Net P

POSTRETIREMENT BENEFITS - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Weighted-average assumptions used to determine net periodic pension cost during the period:
Discount rate	2.70%	2.50%	3.10%
Expected return on plan assets	4%	6.20%	6.30%
Pension Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Interest cost	$ 2,958	$ 2,729	$ 3,739
Expected return on plan assets	(5,392)	(6,424)	(6,331)
Amortization of actuarial loss	631	1,327	888
Net periodic cost	$ (1,803)	$ (2,368)	$ (1,704)

POSTRETIREMENT BENEFITS - Chang

POSTRETIREMENT BENEFITS - Change in Benefit Obligations (Details) - Pension Plan - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Change in benefit obligations:
Beginning balance, benefit obligations	$ 140,745	$ 146,759
Interest cost	2,958	2,729	$ 3,739
Actuarial loss	(36,411)	(3,170)
Benefits and administrative expenses paid	(6,090)	(5,573)
Ending balance, benefit obligations	101,202	140,745	146,759
Change in plan assets:
Beginning balance, fair value of plan assets	138,056	106,736
Actual return on plan assets	(28,230)	17,258
Employer contributions	188	19,635
Benefits and administrative expenses paid	(6,090)	(5,573)
Ending balance, fair value of plan assets	103,925	138,056	$ 106,736
Amounts recognized in the consolidated balance sheets consist of:
Pension Non-Current Assets	2,723	1,130
Pension liabilities	0	(3,819)
Net amount recognized	2,723	(2,689)
Amounts recognized in accumulated other comprehensive loss (before income taxes) consist of:
Net actuarial loss	(23,616)	(27,036)
Total loss recognized	$ (23,616)	$ (27,036)
Weighted-average assumptions used to determine pension benefit obligations at year end:
Discount rate	5.40%	2.70%

POSTRETIREMENT BENEFITS - Benef

POSTRETIREMENT BENEFITS - Benefit Obligation In Excess Of Plan Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plan, Pension Plan with Project Benefit Obligation in Excess of Plan Assets [Abstract]
Accumulated benefit obligation	$ 0	$ 122,655
Fair value of plan assets	0	118,843
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	0	122,655
Fair value of plan assets	$ 0	$ 118,843

POSTRETIREMENT BENEFITS - Narra

POSTRETIREMENT BENEFITS - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plans expense	$ 4,615	$ 3,400	$ 3,718
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	188	19,635
Estimated employer contributions in next fiscal year	234
Multiemployer Plan [Line Items]
Liability	$ 4,685	$ 5,021
Pension Plan | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Policy target allocation (as a percentage)	50%
Pension Plan | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Policy target allocation (as a percentage)	50%

POSTRETIREMENT BENEFITS - Weigh

POSTRETIREMENT BENEFITS - Weighted-Average Asset Allocations (Details) - Pension Plan	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	100%	100%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	50%	56%
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	46%	43%
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Plan asset allocations	4%	1%

POSTRETIREMENT BENEFITS - Asset

POSTRETIREMENT BENEFITS - Asset Allocations by Fair Value Hierarchy (Details) - Pension Plan - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 103,925	$ 138,056	$ 106,736
United States equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29,583	48,274
Non-U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22,913	28,787
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	47,433	59,488
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,996	1,507
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	79,131	138,056
Level 1 | United States equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29,583	48,274
Level 1 | Non-U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22,913	28,787
Level 1 | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22,639	59,488
Level 1 | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,996	1,507
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24,794	0
Level 2 | United States equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 | Non-U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24,794	0
Level 2 | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0

POSTRETIREMENT BENEFITS - Futur

POSTRETIREMENT BENEFITS - Future Expected Benefit Payments (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Retirement Benefits [Abstract]
2023	$ 6,693
2024	6,893
2025	7,101
2026	7,294
2027	7,390
2028 to 2032	$ 37,238

STOCK INCENTIVE PLAN - Narrativ

STOCK INCENTIVE PLAN - Narrative (Details) - USD ($) $ in Thousands, shares in Millions		12 Months Ended
	Nov. 21, 2019	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense		$ 17,245	$ 17,047	$ 13,064
Employee service share-based compensation, tax benefit from compensation expense		$ 1,634	$ 2,073	$ 3,014
2020 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance (shares)	2
Life of awards	10 years

STOCK INCENTIVE PLAN - Stock Op

STOCK INCENTIVE PLAN - Stock Options Assumptions (Details) - Stock Options	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0%	0%	0%
Expected volatility	49%	59%	36%
Range of risk-free interest rates	1.40%	0.52%
Range of risk free interest rates, minimum			1.67%
Range of risk free interest rates, maximum
Range of expected option lives	6 years	6 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of expected option lives			6 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of expected option lives

STOCK INCENTIVE PLAN - Stock _2

STOCK INCENTIVE PLAN - Stock Options Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Shares
Outstanding, beginning balance (shares)	769	1,375	1,836
Granted (shares)	42	72	67
Exercised (shares)	(98)	(678)	(508)
Forfeited (shares)	0	0	(20)
Outstanding, ending balance (shares)	713	769	1,375
Exercisable (shares)	505
Weighted-Average Exercise Price
Outstanding, beginning balance (in dollars per share)	$ 19.95	$ 15.66	$ 12.94
Granted (in dollars per share)	105.94	29.80	37.24
Exercised (in dollars per share)	12.58	12.30	8.55
Forfeited (in dollars per share)	0	0	19.13
Outstanding, ending balance (in dollars per share)	26	19.95	15.66
Exercisable (in dollars per share)	18.56
Stock Options, Additional Disclosures
Weighted average grant date fair value of options granted (in dollars per share)	49.39
Weighted average grant date fair value, options outstanding (in dollars per share)	13.29	10.89
Weighted average grant date fair value of options exercised (in dollars per share)	$ 9.84
Outstanding, aggregate intrinsic value	$ 38,062	$ 51,441	$ 11,443	$ 31,957
Exercised, aggregate intrinsic value	8,703	$ 33,075	$ 14,548
Exercisable, aggregate intrinsic value	$ 29,938
Outstanding, weighted average remaining contractual term (in years)	5 years 2 months 19 days
Exercisable, weighted average remaining contractual term (in years)	4 years 4 months 17 days

STOCK INCENTIVE PLAN - Stock _3

STOCK INCENTIVE PLAN - Stock Options Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of common stock, net of taxes withheld	$ (24,045)	$ 2,660	$ (2,972)
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 948
Weighted-average period (years)	5 years 2 months 12 days
Fair value of shares vested	$ 1,447	1,465	1,894
Issuance of common stock, net of taxes withheld	1,230	8,535	4,347
Tax benefit for tax deductions from stock options exercised	$ 2,176	$ 8,228	$ 3,681

STOCK INCENTIVE PLAN - Restrict

STOCK INCENTIVE PLAN - Restricted Stock Narrative (Details) - Restricted Stock Units (RSUs) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years
Unrecognized compensation expense	$ 7,712
Weighted-average period (years)	1 year 3 months 18 days
Fair value of shares vested in period	$ 20,342	$ 8,897	$ 14,513

STOCK INCENTIVE PLAN - Schedule

STOCK INCENTIVE PLAN - Schedule of Nonvested Restricted Stock (Details) - Restricted Stock Units (RSUs) - $ / shares shares in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Shares
Nonvested, beginning balance (shares)	384	405	674
Nonvested, granted (shares)	100	218	166
Nonvested, vested (shares)	(208)	(229)	(403)
Nonvested, forfeited (shares)	(14)	(10)	(32)
Nonvested, ending balance (shares)	262	384	405
Weighted-average grant-date fair value
Nonvested, beginning of year (in dollars per share)	$ 30.30	$ 26.44	$ 19.37
Nonvested, granted (in dollars per share)	103.94	32.01	37.24
Nonvested, vested (in dollars per share)	27.40	23.78	19.43
Nonvested, forfeited (in dollars per share)	49.23	28.48	22.29
Nonvested, ending of year (in dollars per share)	$ 58.72	$ 30.30	$ 26.44

STOCK INCENTIVE PLAN - Performa

STOCK INCENTIVE PLAN - Performance Share Units Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Closing stock price (in dollars per share)	$ 105.94	$ 29.80	$ 37.24
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance condition, percentage of the award and a market condition	70%
Performance condition, peer group, remaining percentage	30%
Award vesting period (years)	3 years
Unrecognized compensation expense	$ 5,369
Weighted-average period (years)	11 months 15 days

STOCK INCENTIVE PLAN - Perfor_2

STOCK INCENTIVE PLAN - Performance Share Assumptions (Details) - Performance Shares - $ / shares	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0%	0%	0%
Expected volatility	63%
Expected volatility, minimum		61%	21%
Expected volatility, maximum			53%
Range of risk-free interest rates	0.83%	0.21%	1.59%
Expected life	3 years	3 years	3 years
Fair value (in dollars per share)	$ 122.25	$ 33.80	$ 44.22

STOCK INCENTIVE PLAN - Schedu_2

STOCK INCENTIVE PLAN - Schedule of Nonvested Performance Shares (Details) - $ / shares shares in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested, beginning balance (shares)	453	425	455
Shares issued (shares)	52	156	115
Nonvested, vested (shares)	(381)	(171)	(162)
Adjustment for achieved performance (shares)	190	57	31
Nonvested, forfeited (shares)	(1)	(14)	(14)
Nonvested, ending balance (shares)	313	453	425
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Nonvested, beginning of year (in dollars per share)	$ 28.07	$ 25.15	$ 21.11
Grant date fair value (in dollars per share)	113.51	31.67	40.43
Nonvested, vested (in dollars per share)	18.17	21.55	25.21
Adjustment for achieved performance (in dollars per share)	18.17	22.95	21.68
Nonvested, forfeited (in dollars per share)	57.61	29.43	22.82
Nonvested, ending of year (in dollars per share)	$ 48.19	$ 28.07	$ 25.15
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested, beginning balance (shares)	384	405	674
Shares issued (shares)	100	218	166
Nonvested, vested (shares)	(208)	(229)	(403)
Nonvested, forfeited (shares)	(14)	(10)	(32)
Nonvested, ending balance (shares)	262	384	405
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Nonvested, beginning of year (in dollars per share)	$ 30.30	$ 26.44	$ 19.37
Grant date fair value (in dollars per share)	103.94	32.01	37.24
Nonvested, vested (in dollars per share)	27.40	23.78	19.43
Nonvested, forfeited (in dollars per share)	49.23	28.48	22.29
Nonvested, ending of year (in dollars per share)	$ 58.72	$ 30.30	$ 26.44

OTHER INCOME, NET (Details)

OTHER INCOME, NET (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Other Income, Nonoperating [Abstract]
Gain on purchase of business	$ 0	$ (731)	$ 0
Undesignated foreign currency derivative instruments	(4,379)	2,201	1,269
Business interruption insurance recovery	0	(15,500)	0
Foreign exchange loss (gain) on intercompany loans	5,342	(1,534)	(2,342)
Pension-related benefits	(1,803)	(2,368)	(1,704)
Other	350	(220)	0
Other income, net	$ (490)	$ (18,152)	$ (2,777)

INCOME TAXES - Components of In

INCOME TAXES - Components of Income (Loss) from Continuing Operations and Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Components of income before income taxes:
United States	$ 1,174,109	$ 770,350	$ 201,784
Non-U.S	29,511	9,651	214
Income before income taxes	1,203,620	780,001	201,998
United States:
Federal	228,141	182,105	32,335
State	49,793	46,913	9,668
Non-U.S:	9,198	6,432	3,210
Current income tax expense	287,132	235,450	45,213
United States:
Federal	3,174	(35,442)	5,102
State	753	(7,281)	49
Non-U.S:	(873)	(583)	(668)
Deferred income (benefit) tax expense	3,054	(43,306)	4,483
Income tax expense	$ 290,186	$ 192,144	$ 49,696

INCOME TAXES - Differences Betw

INCOME TAXES - Differences Between Federal Income Tax Rate and Effective Income Tax Rate (Details)	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Statutory federal tax	21%	21%	21%
Adjustments to reconcile to the effective income tax rate:
State income taxes	3%	4%	4%
Stock-based compensation	(1.00%)	(1.00%)	(2.00%)
Other	1%	1%	2%
Effective income tax rate	24%	25%	25%

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Operating Loss Carryforwards [Line Items]
State income tax expense	$ 39,759	$ 30,680	$ 7,690
Limitations on executive compensation	6,996	2,587	1,243
Excess tax benefit from share-based compensation	$ 11,438	7,352	4,203
Current year valuation allowance expense		2,190	2,099
Operating loss carryforwards expiration term (year)	5 years
Unrecognized tax benefits	$ 985	3,333	1,614	$ 794
Accrued interest and penalties	77	260
Settlements	(3,012)	(230)	(227)
Increase of unrecognized tax benefits related to various state jurisdictions' uncertain tax positions	664
Increase (decrease) of accrued penalties and interest for uncertain tax positions	(183)	72	134
Unrecognized tax benefits, increase		$ 1,949	$ 1,047
Undistributed income	100,493
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carrying forwards	12,942
State
Operating Loss Carryforwards [Line Items]
Operating loss carrying forwards	29,094
Non-U.S.
Operating Loss Carryforwards [Line Items]
Operating loss carrying forwards	$ 52,250

INCOME TAXES - Components of Ne

INCOME TAXES - Components of Net Deferred Income Tax Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Deferred tax assets:
Accrued liabilities and reserves	$ 47,582	$ 42,932
Tax loss and credit carryforwards	17,272	16,096
Postretirement benefits	583	2,057
Inventory	29,501	36,021
Lease obligations	17,779	10,616
Other	1,079	633
Deferred tax assets	113,796	108,355
Deferred tax liabilities:
Property, plant and equipment	(28,475)	(21,784)
Intangible assets	(56,886)	(43,657)
Loss on investment	0	(5,102)
Right-of-use assets, net	(17,095)	(10,247)
Other	(4,156)	(3,095)
Deferred tax liabilities	(106,612)	(83,885)
Net deferred tax liability before valuation allowance	7,184	24,470
Valuation allowance	(13,415)	(11,523)
Net deferred tax liability	$ (6,231)
Net deferred tax assets		$ 12,947

INCOME TAXES - Unrecognized Tax

INCOME TAXES - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 3,333	$ 1,614	$ 794
Additions based on tax positions related to prior years	322	291	925
Additions based on tax positions related to current year	342	1,658	122
Settlements	(3,012)	(230)	(227)
Ending balance	$ 985	$ 3,333	$ 1,614

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net income	$ 913,434	$ 587,857	$ 152,302
Less: Undistributed earnings allocated to participating securities	14,460	11,380	3,356
Net income available to common shareholders, basic	898,974	576,477	148,946
Net income available to common shareholders, diluted	$ 898,974	$ 576,477	$ 148,946
Denominator:
Basic weighted average common shares outstanding (in shares)	43,717	46,569	47,265
Effect of dilutive securities: non-participating employee stock options (shares)	563	737	779
Diluted weighted average common shares outstanding (shares)	44,280	47,306	48,044
Basic earnings per share (in dollars per share)	$ 20.56	$ 12.38	$ 3.15
Diluted earnings per share (in dollars per share)	$ 20.30	$ 12.19	$ 3.10
Common Stock
Denominator:
Antidilutive securities excluded from computation of earnings per share, amount	0	0	300

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE LOSS - Schedule of Change in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 864,736	$ 378,410	$ 232,936
Other comprehensive (loss) income before reclassifications	(21,892)	12,838
Amounts reclassified from accumulated other comprehensive loss	472	990
Total other comprehensive (loss) income	(21,420)	13,828	(856)
Balance at end of period	1,249,787	864,736	378,410
Defined benefit pension items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(19,318)	(30,761)
Other comprehensive (loss) income before reclassifications	2,051	10,453
Amounts reclassified from accumulated other comprehensive loss	472	990	661
Total other comprehensive (loss) income	2,523	11,443
Balance at end of period	(16,795)	(19,318)	(30,761)
Currency translation adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(9,408)	(11,793)
Other comprehensive (loss) income before reclassifications	(23,943)	2,385
Amounts reclassified from accumulated other comprehensive loss	0	0
Total other comprehensive (loss) income	(23,943)	2,385
Balance at end of period	(33,351)	(9,408)	(11,793)
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(28,726)	(42,554)	(41,698)
Total other comprehensive (loss) income	(21,420)	13,828	(856)
Balance at end of period	$ (50,146)	$ (28,726)	$ (42,554)

ACCUMULATED OTHER COMPREHENSI_4

ACCUMULATED OTHER COMPREHENSIVE LOSS - Summary of Amounts Reclassified (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net reclassifications for the period	$ 472	$ 990
Defined benefit pension items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of net loss (included within other income, net)	631	1,327	$ 888
Tax expense	(159)	(337)	(227)
Net reclassifications for the period	$ 472	$ 990	$ 661

INVENTORIES, NET - Narrative (D

INVENTORIES, NET - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Inventory Disclosure [Abstract]
Inventories at lower of LIFO cost or market	82%	81%
FIFO inventory, higher than reported	$ 64,550	$ 108,911
Effect of LIFO inventory liquidation on operating income	248	6,592
Inventory Valuation Reserves	$ (18,996)	$ (11,780)

INVENTORIES, NET - Schedule of

INVENTORIES, NET - Schedule of Company Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Inventory Disclosure [Abstract]
Purchased materials and manufactured parts, net	$ 166,038	$ 105,460
Work in process, net	61,182	35,043
Finished goods, net	227,291	145,486
Inventories, net	$ 454,511	$ 285,989

PROPERTY, PLANT AND EQUIPMENT -

PROPERTY, PLANT AND EQUIPMENT - Schedule of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 769,093	$ 613,289
Accumulated depreciation	(378,873)	(337,667)
Property, plant and equipment, net	390,220	275,622
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	22,113	23,043
Buildings and related improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	172,633	136,680
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	427,460	372,503
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	10,512	9,720
Software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	36,884	28,288
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 99,491	$ 43,055

PROPERTY, PLANT AND EQUIPMENT_2

PROPERTY, PLANT AND EQUIPMENT - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 48,239	$ 44,913	$ 42,208

GOODWILL AND INTANGIBLE ASSET_2

GOODWILL AND INTANGIBLE ASSETS - Goodwill (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Goodwill [Roll Forward]
Balance at beginning of period	$ 199,048	$ 188,239
Goodwill acquired during year	97,395	9,948
Exchange rate effects	(7,113)	861
Balance at end of period	289,330	199,048
Electrical
Goodwill [Roll Forward]
Balance at beginning of period	155,471	144,662
Goodwill acquired during year	87,964	9,948
Exchange rate effects	(6,727)	861
Balance at end of period	236,708	155,471
Safety & Infrastructure
Goodwill [Roll Forward]
Balance at beginning of period	43,577	43,577
Goodwill acquired during year	9,431	0
Exchange rate effects	(386)	0
Balance at end of period	$ 52,622	$ 43,577

GOODWILL AND INTANGIBLE ASSET_3

GOODWILL AND INTANGIBLE ASSETS - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Indefinite-lived Intangible Assets [Line Items]
Amortization expense	$ 36,176	$ 33,644	$ 32,262
Electrical
Indefinite-lived Intangible Assets [Line Items]
Accumulated impairment loss	$ 3,924
Safety & Infrastructure
Indefinite-lived Intangible Assets [Line Items]
Accumulated impairment loss		$ 43,000

GOODWILL AND INTANGIBLE ASSET_4

GOODWILL AND INTANGIBLE ASSETS - Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Amortizable intangible assets:
Gross Carrying Value	$ 568,449	$ 394,681
Accumulated Amortization	(278,542)	(246,357)
Net Carrying Value	289,907	148,324
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Value	661,248	487,561
Net Carrying Value	382,706	241,204
Trade names
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Carrying value	92,799	92,880
Customer relationships
Amortizable intangible assets:
Gross Carrying Value	532,768	371,048
Accumulated Amortization	(267,940)	(234,946)
Net Carrying Value	$ 264,828	136,102
Customer relationships | Weighted Average
Amortizable intangible assets:
Weighted Average Useful Life (Years)	11 years
Other
Amortizable intangible assets:
Gross Carrying Value	$ 35,681	23,633
Accumulated Amortization	(10,602)	(11,411)
Net Carrying Value	$ 25,079	$ 12,222
Other | Weighted Average
Amortizable intangible assets:
Weighted Average Useful Life (Years)	8 years

GOODWILL AND INTANGIBLE ASSET_5

GOODWILL AND INTANGIBLE ASSETS - Expected Amortization Expense (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2023	$ 50,650
2024	47,457
2025	36,938
2026	32,515
2027	30,537
2028 and thereafter	$ 91,810

DEBT - Schedule of Debt (Detail

DEBT - Schedule of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Debt Instrument [Line Items]
Deferred financing costs	$ (10,844)	$ (12,709)
Long-term debt	760,537	758,386
Secured Debt
Debt Instrument [Line Items]
Carrying Value	773,000,000	773,000
Secured Debt | New Senior Secured Term Loan Facility due May 26, 2028
Debt Instrument [Line Items]
Carrying Value	371,381	371,095
Secured Debt | Senior Notes Due June 1, 2031
Debt Instrument [Line Items]
Carrying Value	400,000	400,000
Secured Debt | ABL Credit Facility
Debt Instrument [Line Items]
Carrying Value	$ 0	$ 0

DEBT - First Lien Loan - Narrat

DEBT - First Lien Loan - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Repayments of long-term debt		$ 0	$ 835,120	$ 40,000
Atkore International | New Senior Secured Term Loan Facility due May 26, 2028 | Secured Debt
Debt Instrument [Line Items]
Repayments of long-term debt	$ 26,000

DEBT - Contractual Obligation (

DEBT - Contractual Obligation (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Debt Disclosure [Abstract]
2023	$ 0
2024	0
2025	0
2026	0
2027	0
2028 and thereafter	$ 773,000

DEBT - New Senior Secured Term

DEBT - New Senior Secured Term Loan Facility - Narrative (Details) - Secured Debt - Senior Term Loan Facility Due May 26, 2028	May 26, 2021 USD ($)
Debt Instrument [Line Items]
Debt instrument, face amount	$ 400,000,000
Debt instrument, annual amortization rate	1%
LIBOR
Debt Instrument [Line Items]
LIBOR floor rate (%)	0.50%
Debt instrument, basis spread on variable rate	2%
Alternate Base Rate
Debt Instrument [Line Items]
LIBOR floor rate (%)	1.50%
Debt instrument, basis spread on variable rate	1%

DEBT - Senior Notes - Narrative

DEBT - Senior Notes - Narrative (Details) - Senior Notes - Senior Notes due June 2031	May 26, 2021 USD ($)
Debt Instrument [Line Items]
Debt instrument, face amount	$ 400,000,000
Debt instrument, interest rate, stated percentage	4.25%

DEBT - ABL Credit Facility - Na

DEBT - ABL Credit Facility - Narrative (Details) - USD ($)			12 Months Ended
	May 26, 2021	Aug. 28, 2020	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Gain (loss) on extinguishment of debt			$ 0	$ (4,202,000)	$ (273,000)
Atkore International | Domestic Line of Credit | ABL Credit Facility | LIBOR | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.75%
Atkore International | Domestic Line of Credit | ABL Credit Facility | LIBOR | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		2.25%
Atkore International | Domestic Line of Credit | ABL Credit Facility | Alternate Base Rate | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.75%
Atkore International | Domestic Line of Credit | ABL Credit Facility | Alternate Base Rate | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.25%
Atkore International | Domestic Line of Credit | Amended ABL Credit Facility | LIBOR | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.25%
Atkore International | Domestic Line of Credit | Amended ABL Credit Facility | LIBOR | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.75%
Atkore International | Domestic Line of Credit | Amended ABL Credit Facility | Alternate Base Rate | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.25%
Atkore International | Domestic Line of Credit | Amended ABL Credit Facility | Alternate Base Rate | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.75%
Atkore International | Foreign Line of Credit | ABL Credit Facility
Debt Instrument [Line Items]
Line of credit facility, unused capacity, commitment fee percentage		0.375%
Atkore International | Foreign Line of Credit | ABL Credit Facility | Bankers Acceptance Rate | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.75%
Atkore International | Foreign Line of Credit | ABL Credit Facility | Bankers Acceptance Rate | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		2.25%
Atkore International | Foreign Line of Credit | ABL Credit Facility | Prime Rate | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.75%
Atkore International | Foreign Line of Credit | ABL Credit Facility | Prime Rate | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.25%
Atkore International | Foreign Line of Credit | Amended ABL Credit Facility | Line Of Credit Facility, Commitment Option One
Debt Instrument [Line Items]
Line of credit facility, unused capacity, commitment fee percentage	0.375%
Atkore International | Foreign Line of Credit | Amended ABL Credit Facility | Line Of Credit Facility, Commitment Option Two
Debt Instrument [Line Items]
Line of credit facility, unused capacity, commitment fee percentage	0.30%
Atkore International | Foreign Line of Credit | Amended ABL Credit Facility | Line Of Credit Facility, Commitment Option Three
Debt Instrument [Line Items]
Line of credit facility, unused capacity, commitment fee percentage	0.25%
Atkore International | Foreign Line of Credit | Amended ABL Credit Facility | Bankers Acceptance Rate | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.25%
Atkore International | Foreign Line of Credit | Amended ABL Credit Facility | Bankers Acceptance Rate | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.75%
Atkore International | Foreign Line of Credit | Amended ABL Credit Facility | Prime Rate | Minimum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.25%
Atkore International | Foreign Line of Credit | Amended ABL Credit Facility | Prime Rate | Maximum
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.75%
Atkore International | Line of Credit | Amended ABL Credit Facility
Debt Instrument [Line Items]
Aggregate commitments			325,000,000
Credit availability			$ 312,905,000	315,499,000
Borrowing base percentage of eligible accounts receivable (%)			85%
Borrowing base percentage of eligible inventory (plus) (%)			80%
Debt instrument, covenant, borrowing base, percentage of inventory subject to certain limitations (%)			85%
Borrowings outstanding			$ 0	$ 0
Atkore International | Line of Credit | Amended ABL Credit Facility | Secured Debt
Debt Instrument [Line Items]
Debt instrument, extended term, period from amendment date	5 years
Debt instrument, extended term, period prior to maturity date	91 days
Line of credit facility, term, outstanding obligations threshold amount	$ 100,000,000

DEBT - Use of Proceeds - Narrat

DEBT - Use of Proceeds - Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
	May 26, 2021	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Debt Instrument [Line Items]
Loss on extinguishment of debt		$ 0	$ 4,202	$ 273
First Lien Term Loan Facility due December 22, 2023 | Secured Debt
Debt Instrument [Line Items]
Repayments of debt	$ 772,000
Repayment of debt interest	4,000
Loss on extinguishment of debt	$ 4,200

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details) - GBP (£)	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Foreign Exchange Contract
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Notional Amount	£ 0	£ 37,400,000	£ 43,300,000

FAIR VALUE MEASUREMENTS - Asset

FAIR VALUE MEASUREMENTS - Assets and Liabilities Measured at Fair Value (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Level 1
Assets
Cash equivalents	$ 291,757	$ 489,987
Forward currency contracts	0	0
Liabilities
Forward currency contracts	0	0
Level 2
Assets
Cash equivalents	0	0
Forward currency contracts	0	127
Liabilities
Forward currency contracts	0	183
Level 3
Assets
Cash equivalents	0	0
Forward currency contracts	0	0
Liabilities
Forward currency contracts	$ 0	$ 0

FAIR VALUE MEASUREMENTS - Estim

FAIR VALUE MEASUREMENTS - Estimated Fair Value of Financial Instruments Not Carried at Fair Value (Details) - Secured Debt - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	$ 773,000,000	$ 773,000
Fair Value	689,115	787,314
New Senior Secured Term Loan Facility due May 26, 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	373,000	373,000
Fair Value	370,203	371,486
Senior Notes due June 2031
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	400,000	400,000
Fair Value	$ 318,912	$ 415,828

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Purchase obligation for fiscal 2023	$ 175,282
Purchase obligation for fiscal 2024	4,731
Purchase obligation thereafter	5,600
Business interruption insurance recovery	0	$ 15,500	$ 0
Minimum
Loss Contingencies [Line Items]
Probable losses	1,000
Maximum
Loss Contingencies [Line Items]
Probable losses	$ 8,000

GUARANTEES (Details)

GUARANTEES (Details) $ in Thousands	Sep. 30, 2022 USD ($)
Workers' Compensation and General Liability Insurance Policies
Guarantor Obligations [Line Items]
Guarantees	$ 12,095
Surety Bond
Guarantor Obligations [Line Items]
Guarantees	$ 26,782

SEGMENT INFORMATION - Schedule

SEGMENT INFORMATION - Schedule of Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Net sales	$ 3,913,949	$ 2,928,014	$ 1,765,421
Capital Expenditures	135,776	64,474	33,770
Total Assets	2,598,996	2,210,099	1,558,525
Electrical
Segment Reporting Information [Line Items]
Net sales	3,013,755	2,229,862	1,267,988
Safety & Infrastructure
Segment Reporting Information [Line Items]
Net sales	900,194	698,152	497,433
Operating Segments
Segment Reporting Information [Line Items]
Net sales	3,913,949	2,928,014	1,765,421
Adjusted EBITDA	1,411,800	955,695	360,630
Operating Segments | Electrical
Segment Reporting Information [Line Items]
Net sales	3,013,755	2,229,862	1,267,988
Adjusted EBITDA	1,273,410	873,868	292,809
Capital Expenditures	61,721	34,995	16,067
Total Assets	1,524,670	1,122,835	794,931
Operating Segments | Safety & Infrastructure
Segment Reporting Information [Line Items]
Net sales	900,194	698,152	497,433
Adjusted EBITDA	138,390	81,827	67,821
Capital Expenditures	38,280	22,407	15,470
Total Assets	618,331	482,942	255,903
Intersegment Sales
Segment Reporting Information [Line Items]
Net sales	(394)	(3,605)	(2,649)
Intersegment Sales | Electrical
Segment Reporting Information [Line Items]
Net sales	0	3,437	2,559
Intersegment Sales | Safety & Infrastructure
Segment Reporting Information [Line Items]
Net sales	394	168	90
Unallocated
Segment Reporting Information [Line Items]
Capital Expenditures	35,775	7,072	2,233
Total Assets	$ 455,995	$ 604,322	$ 507,691

SEGMENT INFORMATION - Reconcili

SEGMENT INFORMATION - Reconciliation of Operating Segment Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Unallocated expenses	$ (70,010)	$ (58,148)	$ (33,995)
Depreciation and amortization	(84,415)	(78,557)	(74,470)
Interest expense, net	(30,676)	(32,899)	(40,062)
Loss on extinguishment of debt	0	(4,202)	(273)
Stock-based compensation	(17,245)	(17,047)	(13,064)
Transaction costs	(3,424)	(667)	(196)
Other	(2,410)	15,826	3,428
Income before income taxes	1,203,620	780,001	201,998
Operating Segments
Segment Reporting Information [Line Items]
Adjusted EBITDA	1,411,800	955,695	360,630
Operating Segments | Electrical
Segment Reporting Information [Line Items]
Adjusted EBITDA	1,273,410	873,868	292,809
Operating Segments | Safety & Infrastructure
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 138,390	$ 81,827	$ 67,821

SEGMENT INFORMATION - Schedul_2

SEGMENT INFORMATION - Schedule of Long-lived Assets and Net Sales By Geography (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	$ 461,255	$ 316,735	$ 246,882
Net sales	3,913,949	2,928,014	1,765,421
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	410,263	258,069	203,694
Net sales	3,552,893	2,637,118	1,563,258
Other Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	7,195	6,180	146
Net sales	102,626	53,151	26,421
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	38,396	45,917	41,283
Net sales	213,581	183,985	132,299
Asia-Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	5,400	6,569	1,759
Net sales	$ 44,849	$ 53,760	$ 43,443

SEGMENT INFORMATION - Schedul_3

SEGMENT INFORMATION - Schedule of Net Sales From External Customers by Product Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Revenue from External Customer [Line Items]
Net sales	$ 3,913,949	$ 2,928,014	$ 1,765,421
Electrical
Revenue from External Customer [Line Items]
Net sales	3,013,755	2,229,862	1,267,988
Electrical | Metal Electrical Conduit and Fittings
Revenue from External Customer [Line Items]
Net sales	635,481	612,137	484,476
Electrical | Plastic Pipe and Conduit
Revenue from External Customer [Line Items]
Net sales	1,479,331	893,199	308,561
Electrical | Electrical Cable and Flexible Conduit
Revenue from External Customer [Line Items]
Net sales	535,194	424,411	322,888
Electrical | Other Electrical products
Revenue from External Customer [Line Items]
Net sales	363,749	300,115	152,063
Safety & Infrastructure
Revenue from External Customer [Line Items]
Net sales	900,194	698,152	497,433
Safety & Infrastructure | Mechanical Pipe
Revenue from External Customer [Line Items]
Net sales	445,453	395,289	244,902
Safety & Infrastructure | Other Safety & Infrastructure products
Revenue from External Customer [Line Items]
Net sales	$ 454,741	$ 302,863	$ 252,531

SEGMENT INFORMATION - Narrative

SEGMENT INFORMATION - Narrative (Details) - employee	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Jul. 14, 2020
Segment Reporting Information [Line Items]
Employees represented by a union under a collective bargaining agreement (approximately) (%)	18%
Number of employees represented by a union under a collective bargaining agreement			350
Accounts Receivable Benchmark | Customer Concentration Risk | CED National
Segment Reporting Information [Line Items]
Concentration risk, percentage	10%	11%

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - USD ($) shares in Millions		1 Months Ended
	Nov. 07, 2022	Nov. 14, 2022	Nov. 11, 2022	Apr. 26, 2022	Nov. 16, 2021	Jan. 28, 2021	Feb. 05, 2019
Subsequent Event [Line Items]
Stock repurchase program, authorized amount				$ 800,000,000	$ 400,000,000	$ 100,000,000	$ 50,000,000
Subsequent Event
Subsequent Event [Line Items]
Repurchase of stock (in shares)		1.7
Stock repurchased during period		$ 150,100,000
Stock repurchase program, authorized amount			$ 1,300,000,000
Subsequent Event | Elite Polymer
Subsequent Event [Line Items]
Business combination, purchase price	$ 91,600,000

SCHEDULE I - CONDENSED FINANC_2

SCHEDULE I - CONDENSED FINANCIAL INFORMATION - Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Assets
Total Assets	$ 2,598,996	$ 2,210,099	$ 1,558,525
Liabilities and Equity
Total Liabilities	1,349,209	1,345,363
Equity:
Common stock, $0.01 par value, 1,000,000,000 shares authorized, 41,351,350 and 45,997,159 shares issued and outstanding, respectively	415	461
Treasury stock, held at cost, 260,900 and 260,900 shares, respectively	(2,580)	(2,580)
Additional paid-in capital	500,117	506,921
Retained earnings	801,981	388,660
Accumulated other comprehensive loss	(50,146)	(28,726)
Total Equity	1,249,787	864,736	$ 378,410	$ 232,936
Total Liabilities and Equity	2,598,996	2,210,099
Parent Company
Assets
Investment in subsidiary	1,249,787	864,736
Total Assets	1,249,787	864,736
Liabilities and Equity
Total Liabilities	0	0
Equity:
Common stock, $0.01 par value, 1,000,000,000 shares authorized, 41,351,350 and 45,997,159 shares issued and outstanding, respectively	415	461
Treasury stock, held at cost, 260,900 and 260,900 shares, respectively	(2,580)	(2,580)
Additional paid-in capital	500,117	506,921
Retained earnings	801,981	388,660
Accumulated other comprehensive loss	(50,146)	(28,726)
Total Equity	1,249,787	864,736
Total Liabilities and Equity	$ 1,249,787	$ 864,736

SCHEDULE I - CONDENSED FINANC_3

SCHEDULE I - CONDENSED FINANCIAL INFORMATION - Balance Sheets Additional Information (Details) - $ / shares	Sep. 30, 2022	Sep. 30, 2021
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	41,351,350	45,997,159
Common stock, shares outstanding (in shares)	41,351,350	45,997,159
Treasury stock shares (in shares)	260,900	260,900
Parent Company
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	41,351,350	45,997,159
Common stock, shares outstanding (in shares)	41,351,350	45,997,159
Treasury stock shares (in shares)	260,900	260,900

SCHEDULE I - CONDENSED FINANC_4

SCHEDULE I - CONDENSED FINANCIAL INFORMATION - Condensed Statements of Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Condensed Income Statements, Captions [Line Items]
Net income	$ 913,434	$ 587,857	$ 152,302
Other comprehensive (loss) income of subsidiary, net of tax	(21,420)	13,828	(856)
Comprehensive income	892,014	601,685	151,446
Parent Company
Condensed Income Statements, Captions [Line Items]
Net income	913,434	587,857	152,302
Other comprehensive (loss) income of subsidiary, net of tax	(21,420)	13,828	(856)
Comprehensive income	$ 892,014	$ 601,685	$ 151,446

SCHEDULE I - CONDENSED FINANC_5

SCHEDULE I - CONDENSED FINANCIAL INFORMATION - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Cash Flows from Operating Activities:
Net cash provided by operating activities	$ 786,835	$ 572,902	$ 248,762
Cash Flows from Investing Activities:
Net cash used for investing activities	(442,802)	(97,961)	(27,513)
Cash Flows from Financing Activities:
Repurchase of common stock	(500,161)	(135,066)
Net cash used for financing activities	(524,206)	(184,456)	(61,179)
Increase (decrease) in cash and cash equivalents	(187,538)	291,818	161,056
Cash and cash equivalents:
Cash and cash equivalents at beginning of period	576,289
Cash and cash equivalents at end of period	388,751	576,289
Parent Company
Cash Flows from Operating Activities:
Net cash provided by operating activities	0	0	0
Cash Flows from Investing Activities:
Distribution received from subsidiary	500,161	135,066	15,011
Distribution paid to subsidiary	24,045	(2,660)	2,972
Net cash used for investing activities	524,206	132,406	17,983
Cash Flows from Financing Activities:
Issuance of common stock, net of taxes withheld	(24,045)	2,660	(2,972)
Repurchase of common stock	(500,161)	(135,066)	(15,011)
Net cash used for financing activities	(524,206)	(132,406)	(17,983)
Increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents:
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	$ 0	$ 0	$ 0

SCHEDULE I - CONDENSED FINANC_6

SCHEDULE I - CONDENSED FINANCIAL INFORMATION - Narrative (Details) - USD ($) $ in Thousands, shares in Millions			12 Months Ended
	Apr. 09, 2014	Mar. 06, 2014	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020	Dec. 22, 2010
Condensed Financial Statements, Captions [Line Items]
Payment to redeem shares	$ 250,000
Parent Company
Condensed Financial Statements, Captions [Line Items]
Distribution received from subsidiary			$ 500,161	$ 135,066	$ 15,011
Common Stock
Condensed Financial Statements, Captions [Line Items]
Non-binding letter of intent to acquire common stock (in shares)		40.3
Expense related to share redemption	$ 2,000
Atkore International | CD&R
Condensed Financial Statements, Captions [Line Items]
Preferred stock, percentage of outstanding capital stock (on an as-converted basis) (%)						51%
Common stock, percentage of outstanding capital stock (%)						49%

SCHEDULE II - VALUATION AND Q_2

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Accounts Receivable Allowance for Current and Expected Credit Losses:
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ (2,510)	$ (3,167)	$ (2,608)
Additional (Charges)/Benefit to Income	(1,276)	(339)	(1,990)
Write offs and Other	1,242	996	1,431
Balance at End of Year	(2,544)	(2,510)	(3,167)
Deferred Tax Valuation Allowance:
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	(11,523)	(10,203)	(7,764)
Additional (Charges)/Benefit to Income	(5,265)	(2,190)	(2,047)
Write offs and Other	3,373	870	(392)
Balance at End of Year	$ (13,415)	$ (11,523)	$ (10,203)

Uncategorized Items - atkr-2022

Label	Element	Value
Accounting Standards Update [Extensible Enumeration]	us-gaap_AccountingStandardsUpdateExtensibleList	Accounting Standards Update 2016-02 [Member]