Ecovyst (ECVT) 10-Q 3 May 24 2024 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Mar. 31, 2024	Apr. 26, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	001-38221
Entity Registrant Name	Ecovyst Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-3406833
Entity Address, Address Line One	300 Lindenwood Drive
Entity Address, City or Town	Malvern
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19355
City Area Code	(484)
Local Phone Number	617-1200
Title of 12(b) Security	Common stock, par value $0.01 per share
Trading Symbol	ECVT
Security Exchange Name	NYSE
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
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		117,005,486
Entity Central Index Key	0001708035
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Statement [Abstract]
Sales	$ 160,537	$ 160,874
Cost of goods sold	121,314	124,381
Gross profit	39,223	36,493
Selling, general and administrative expenses	21,604	21,119
Other operating expense, net	3,666	6,716
Operating income	13,953	8,658
Equity in net (income) from affiliated companies	(2,072)	(223)
Interest expense, net	13,409	9,832
Other expense (income), net	216	(427)
Income (loss) before income taxes	2,400	(524)
Provision for income taxes	1,179	947
Net income (loss)	$ 1,221	$ (1,471)
Net income (loss) per share:
Basic income per share (in dollars per share)	$ 0.01	$ (0.01)
Diluted income per share (in dollars per share)	$ 0.01	$ (0.01)
Weighted average shares outstanding:
Basic (in shares)	116,955,043	122,178,867
Diluted (in shares)	117,451,149	122,178,867

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 1,221	$ (1,471)
Other comprehensive income (loss), net of tax:
Pension and postretirement costs	(6)	(24)
Net gain (loss) from hedging activities	3,864	(7,920)
Foreign currency translation	(1,684)	2,185
Total other comprehensive income (loss)	2,174	(5,759)
Comprehensive income (loss)	$ 3,395	$ (7,230)

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
ASSETS
Cash and cash equivalents	$ 103,136	$ 88,365
Accounts receivable, net	78,432	81,314
Inventories, net	52,503	45,115
Derivative assets	13,490	13,419
Prepaid and other current assets	20,968	17,774
Total current assets	268,529	245,987
Investments in affiliated companies	413,171	440,198
Property, plant and equipment, net	572,307	576,904
Goodwill	404,252	404,470
Other intangible assets, net	112,928	116,550
Right-of-use lease assets	25,813	24,281
Other long-term assets	33,813	29,361
Total assets	1,830,813	1,837,751
LIABILITIES
Current maturities of long-term debt	9,000	9,000
Accounts payable	33,544	40,195
Operating lease liabilities—current	8,207	8,193
Accrued liabilities	56,756	61,693
Total current liabilities	107,507	119,081
Long-term debt, excluding current portion	857,220	858,946
Deferred income taxes	117,234	115,791
Operating lease liabilities—noncurrent	17,446	16,030
Other long-term liabilities	20,050	22,439
Total liabilities	1,119,457	1,132,287
Commitments and contingencies (Note 15)
EQUITY
Common stock ($0.01 par); authorized shares 450,000,000; issued shares 140,872,846 and 140,744,045 on March 31, 2024 and December 31, 2023, respectively; outstanding shares 117,001,446 and 116,116,895 on March 31, 2024 and December 31, 2023, respectively	1,409	1,407
Preferred stock ($0.01 par); authorized shares 50,000,000; no shares issued or outstanding on March 31, 2024 and December 31, 2023	0	0
Additional paid-in capital	1,096,965	1,102,581
Accumulated deficit	(169,635)	(170,856)
Treasury stock, at cost; shares 23,871,400 and 24,627,150 on March 31, 2024 and December 31, 2023, respectively	(218,599)	(226,710)
Accumulated other comprehensive income (loss)	1,216	(958)
Total equity	711,356	705,464
Total liabilities and equity	$ 1,830,813	$ 1,837,751

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Common stock, par (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares (in shares)	450,000,000	450,000,000
Common stock, issued shares (in shares)	140,872,846	140,744,045
Common stock, outstanding shares (in shares)	117,001,446	116,116,895
Preferred stock, par (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized shares (in shares)	50,000,000	50,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Treasury stock (in shares)	23,871,400	24,627,150

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	(Accumulated deficit)	Treasury stock, at cost	Accumulated other comprehensive income
Beginning balance at Dec. 31, 2022	$ 707,229	$ 1,396	$ 1,091,475	$ (242,010)	$ (149,624)	$ 5,992
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (loss)	(1,471)			(1,471)
Total other comprehensive income (loss)	(5,759)					(5,759)
Other comprehensive income	(5,759)					(5,759)
Repurchases of common shares	(29,850)				(29,850)
Tax withholdings on equity award vesting	(866)				(866)
Stock compensation expense	4,756		4,756
Shares issued under equity incentive plan, net of forfeitures	112	10	102
Ending balance at Mar. 31, 2023	674,151	1,406	1,096,333	(243,481)	(180,340)	233
Beginning balance at Dec. 31, 2023	705,464	1,407	1,102,581	(170,856)	(226,710)	(958)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (loss)	1,221			1,221
Total other comprehensive income (loss)	2,174					2,174
Other comprehensive income	2,174					2,174
Tax withholdings on equity award vesting	(1,218)				(1,218)
Stock compensation expense	3,674		3,674
Shares issued under equity incentive plan, net of forfeitures	41	2	(9,290)		9,329
Ending balance at Mar. 31, 2024	$ 711,356	$ 1,409	$ 1,096,965	$ (169,635)	$ (218,599)	$ 1,216

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities:
Net income (loss)	$ 1,221	$ (1,471)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	18,415	16,692
Amortization	3,518	3,505
Amortization of deferred financing costs and original issue discount	525	508
Foreign currency exchange loss (gain)	169	(437)
Deferred income tax provision	156	2,790
Net loss on asset disposals	648	1,178
Stock compensation	3,680	4,068
Equity in net income from affiliated companies	(2,072)	(223)
Dividends received from affiliated companies	28,000	0
Other, net	(4,385)	(3,775)
Working capital changes that provided (used) cash:
Receivables	2,797	8,364
Inventories	(7,094)	(1,323)
Prepaids and other current assets	(3,258)	(9,732)
Accounts payable	(3,903)	(1,946)
Accrued liabilities	(1,914)	(14,084)
Net cash provided by operating activities	36,503	4,114
Cash flows from investing activities:
Purchases of property, plant and equipment	(17,372)	(18,698)
Net cash used in investing activities	(17,372)	(18,698)
Cash flows from financing activities:
Repayments of long-term debt	(2,250)	(2,250)
Repurchases of common shares	0	(29,850)
Tax withholdings on equity award vesting	(1,218)	(866)
Repayment of financing obligation	(736)	(701)
Other, net	21	97
Net cash used in financing activities	(4,183)	(33,570)
Effect of exchange rate changes on cash and cash equivalents	(177)	(1,147)
Net change in cash and cash equivalents	14,771	(49,301)
Cash and cash equivalents at beginning of period	88,365	110,920
Cash and cash equivalents at end of period	$ 103,136	$ 61,619

Background and Basis of Present

Background and Basis of Presentation	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Background and Basis of Presentation	1. Background and Basis of Presentation: Description of Business Ecovyst Inc. and subsidiaries (the “Company” or “Ecovyst”) is a leading integrated and innovative global provider of advanced materials, specialty catalysts and services. The Company supports customers globally through its strategically located network of manufacturing facilities. The Company believes that its products and services contribute to improving the sustainability of the environment. The Company has two uniquely positioned specialty businesses: Ecoservices provides sulfuric acid recycling to the North American refining industry for the production of alkylate and provides high quality and high strength virgin sulfuric acid for industrial and mining applications. Ecoservices also provides chemical waste handling and treatment services, as well as ex-situ catalyst activation services for the refining and petrochemical industry. Advanced Materials & Catalysts provides finished silica catalysts, catalyst supports and functionalized silicas necessary to produce high performing plastics and to enable sustainable chemistry, and through the Zeolyst Joint Venture, innovates and supplies specialty zeolites used for catalysts that support the production of sustainable fuels, remove nitrogen oxides from diesel engine emissions and that are broadly applied in refining and petrochemical processes. The Company’s regeneration services product group, which is a part of the Company’s Ecoservices segment, typically experiences seasonal fluctuations as a result of higher demand for gasoline products in the summer months and lower demand in the winter months. These demand fluctuations result in higher sales and working capital requirements in the second and third quarters. Basis of Presentation The condensed consolidated financial statements included herein are unaudited. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) have been condensed or omitted pursuant to such rules and regulations for interim reporting. In the opinion of management, all adjustments of a normal and recurring nature necessary to state fairly the financial position and results of operations have been included. The results of operations are not necessarily indicative of the expected results for the full year. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023.

New Accounting Standards

New Accounting Standards	3 Months Ended
	Mar. 31, 2024
Accounting Standards Update and Change in Accounting Principle [Abstract]
New Accounting Standards	2. New Accounting Standards: Accounting Standards Not Yet Adopted In November 2023, the Financial Accounting Standards Board (“FASB”) issued guidance to improve the disclosures related to public business entities reportable segments. This new guidance requires entities to provide information regarding significant segment expenses, especially those segment expenses that are regularly reported to the Company’s chief operating decision maker (the Company’s Chief Executive Officer), or CODM. The guidance also require public entities to disclose the nature, type and amounts of other segment items by reportable segment. Public business entities will also have to report all annual disclosures about segments profits or losses that are required by ASC 280 on an interim basis, including the significant segment expenses and other segment items. The new guidance is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The disclosure will be implemented as required for the fiscal year ended December 31, 2024. The Company is currently evaluating the impact of this guidance. In December 2023, FASB issued guidance to improve disclosures related to incomes taxes. This new guidance requires public business entities to disaggregate information on the effective tax rate reconciliation and income taxes paid to provide greater transparency. Public business entities will be required to provide additional information in specified categories related to effective tax rate reconciliation in tabular form and provide income taxes paid by jurisdictions, with further disaggregation needed if amounts exceed 5% of the total. The new guidance is effective for fiscal years beginning after December 15, 2024. The disclosure will be implemented as required for the fiscal year ended December 31, 2025. The Company is currently evaluating the impact of this guidance. In October 2023, FASB issued guidance to amend either presentation or disclosure requirements related to fourteen subtopics in the FASB Accounting Standards Codification, that are currently in the SEC Regulation S-X or Regulation S-K. The new guidance was issued in response to the SEC’s ruling on disclosure simplification. For entities subject to existing SEC disclosure requirements, the effective date of each amendment of the topics will be the date that the SEC removes the related disclosure from Regulation S-X or Regulation S-K. The guidance must be applied prospectively, with no early adoption permitted for entities subject to those existing SEC disclosures. The Company is currently evaluating the impact of the new guidance as it pertains to the fourteen subtopics that would impact the business and will apply prospectively once in effect. In August 2023, the FASB issued guidance for entities that meet the definition of a joint venture or a corporate joint venture, to adopt a new basis of accounting upon the formation of the joint venture. The new guidance requires the initial measurement of contributed net assets and liabilities at fair value on the formation date, recognition of goodwill for the difference between the fair value of the joint venture’s equity and net assets, and disclosures about the nature and financial impact of the transaction. The new guidance requires prospective application and is effective for all joint ventures that are formed on or after January 1, 2025, with early adoption permitted. Joint ventures that formed before January 1, 2025 may elect to retrospectively apply the new guidance. The Company will apply the guidance to any new joint ventures formed after the effective date.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	3. Revenue from Contracts with Customers: Disaggregated Revenue The Company’s primary means of disaggregating revenues is by reportable segments, which can be found in Note 17 to these condensed consolidated financial statements. The Company’s portfolio of products is integrated into a variety of end uses, which are described in the table below. Key End Uses Key Products Clean fuels, emission control & other • Refining hydrocracking catalysts • Emission control catalysts • Catalyst supports used in production of sustainable fuels such as renewable diesel • Catalysts used in production of sustainable aviation fuels • Catalyst activation • Aluminum sulfate solution • Ammonium bisulfite solution Polyethylene, polymers & engineered plastics • Catalysts for high-density polyethylene and chemicals syntheses • Antiblock for film packaging • Catalyst for advanced recycling Regeneration and treatment services • Sulfuric acid regeneration services • Treatment services Industrial, mining & automotive • Sulfuric acid for mining • Sulfur derivatives for industrial production • Sulfuric derivatives for nylon production The following tables disaggregate the Company’s sales, by segment and end uses, for the three months ended March 31, 2024 and 2023, respectively: Three months ended March 31, 2024 Ecoservices Advanced Materials & Catalyst (2) Total Clean fuels, emission control & other $ 7,389 $ — $ 7,389 Polyethylene, polymers & engineered plastics — 18,935 18,935 Regeneration and treatment services (1) 83,319 — 83,319 Industrial, mining & automotive 50,894 — 50,894 Total segment sales $ 141,602 $ 18,935 $ 160,537 Three months ended March 31, 2023 Ecoservices Advanced Materials & Catalyst (2) Total Clean fuels, emission control & other $ 4,740 $ — $ 4,740 Polyethylene, polymers & engineered plastics — 23,134 23,134 Regeneration and treatment services (1) 88,344 — 88,344 Industrial, mining & automotive 44,656 — 44,656 Total segment sales $ 137,740 $ 23,134 $ 160,874 (1) As described in Note 1 to these condensed consolidated financial statements, the Company experiences seasonal s ales fluctuations to customers in the regeneration services product group. (2) Excludes the Company’s proportionate share of sales from the Zeolyst International and Zeolyst C.V. joint ventures (collectively, the “Zeolyst Joint Venture”) accounted for using the equity method (see Note 9 to these condensed consolidated financial statements for further information).

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements: Fair values are based on quoted market prices when available. When market prices are not available, fair values are generally estimated using discounted cash flow analyses, incorporating current market inputs for similar financial instruments with comparable terms and credit quality. In instances where there is little or no market activity for the same or similar instruments, the Company estimates fair values using methods, models and assumptions that management believes a hypothetical market participant would use to determine a current transaction price. These valuation techniques involve some level of management estimation and judgment that becomes significant with increasingly complex instruments or pricing models. Where appropriate, adjustments are included to reflect the risk inherent in a particular methodology, model or input used. The Company’s financial assets and liabilities carried at fair value have been classified based upon a fair value hierarchy. The hierarchy gives the highest ranking to fair values determined using unadjusted quoted prices in active markets for identical assets and liabilities (Level 1) and the lowest ranking to fair values determined using methodologies and models with unobservable inputs (Level 3). The classification of an asset or a liability is based on the lowest level input that is significant to its measurement. For example, a Level 3 fair value measurement may include inputs that are both observable (Levels 1 and 2) and unobservable (Level 3). The levels of the fair value hierarchy are as follows: • Level 1—Values are unadjusted quoted prices for identical assets and liabilities in active markets accessible at the measurement date. Active markets provide pricing data for trades occurring at least weekly and include exchanges and dealer markets. • Level 2—Inputs include quoted prices for similar assets or liabilities in active markets, quoted prices from those willing to trade in markets that are not active, or other inputs that are observable or can be corroborated by market data for the term of the instrument. Such inputs include market interest rates and volatilities, spreads and yield curves. • Level 3—Certain inputs are unobservable (supported by little or no market activity) and significant to the fair value measurement. Unobservable inputs reflect the Company’s best estimate of what hypothetical market participants would use to determine a transaction price for the asset or liability at the reporting date. The following tables present information about the Company’s assets and liabilities that were measured at fair value on a recurring basis as of March 31, 2024 and December 31, 2023, and indicates the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value. March 31, Quoted Prices in Significant Other Significant Derivative assets: Interest rate caps (Note 12) $ 22,066 $ — $ 22,066 $ — Derivative liabilities: Interest rate caps (Note 12) $ 743 $ — $ 743 $ — December 31, Quoted Prices in Significant Other Significant Derivative assets: Interest rate caps (Note 12) $ 19,021 $ — $ 19,021 $ — Derivative liabilities: Interest rate caps (Note 12) $ 2,496 $ — $ 2,496 $ — Derivative contracts Derivative assets and liabilities can be exchange-traded or traded over-the-counter (“OTC”). The Company generally values exchange-traded derivatives using models that calibrate to market transactions and eliminate timing differences between the closing price of the exchange-traded derivatives and their underlying instruments. OTC derivatives are valued using market transactions and other market evidence whenever possible, including market-based inputs to models, model calibration to market transactions, broker or dealer quotations or alternative pricing sources with reasonable levels of price transparency. When models are used, the selection of a particular model to value an OTC derivative depends on the contractual terms of, and specific risks inherent in, the instrument as well as the availability of pricing information in the market. The Company generally uses similar models to value similar instruments. Valuation models require a variety of inputs, including contractual terms, market prices and rates, forward curves, measures of volatility, and correlations of such inputs. For OTC derivatives that trade in liquid markets, such as forward contracts, swaps and options, model inputs can generally be corroborated by observable market data by correlation or other means, and model selection does not involve significant management judgment. As of March 31, 2024, th e Company had interest rate c aps th at were fair valued using Level 2 inputs. In addition, the Company applies a credit valuation adjustment to reflect credit risk which is calculated based on credit default swaps. To the extent that the Company’s net exposure under a specific master agreement is an asset, the Company utilizes the counterparty’s default swap rate. If the net exposure under a specific master agreement is a liability, the Company utilizes a default swap rate comparable to Ecovyst. The credit valuation adjustment is added to the discounted fair value to reflect the exit price that a market participant would be willing to receive to assume the Company’s liabilities or that a market participant would be willing to pay for the Company’s assets.

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Stockholders' Equity	5. Stockholders' Equity: Accumulated Other Comprehensive Income (Loss) The following tables present the tax effects of each component of other comprehensive income (loss) for the three months ended March 31, 2024 and 2023, respectively: Three months ended March 31, 2024 2023 Pre-tax Tax benefit/ After-tax amount Pre-tax Tax benefit After-tax amount Defined benefit and other postretirement plans: Net loss $ (1) $ — $ (1) $ (1) $ — $ (1) Net prior service cost (7) 2 (5) (31) 8 (23) Benefit plans, net (8) 2 (6) (32) 8 (24) Net gain (loss) from hedging activities 5,152 (1,288) 3,864 (10,303) 2,383 (7,920) Foreign currency translation (1,684) — (1,684) 2,185 — 2,185 Other comprehensive income (loss) $ 3,460 $ (1,286) $ 2,174 $ (8,150) $ 2,391 $ (5,759) The following tables present the changes in accumulated other comprehensive income, net of tax, by component for the three months ended March 31, 2024 and 2023, respectively: Defined benefit Net gain (loss) Foreign Total December 31, 2023 $ 612 $ 12,546 $ (14,116) $ (958) Other comprehensive income (loss) before reclassifications — 7,356 (1,684) 5,672 Amounts reclassified from accumulated other comprehensive loss (1) (6) (3,492) — (3,498) Net current period other comprehensive income (loss) (6) 3,864 (1,684) 2,174 March 31, 2024 $ 606 $ 16,410 $ (15,800) $ 1,216 December 31, 2022 $ (508) $ 24,672 $ (18,172) $ 5,992 Other comprehensive income (loss) before reclassifications (48) (7,394) 2,185 (5,257) Amounts reclassified from accumulated other comprehensive income (loss) (1) 24 (526) — (502) Net current period other comprehensive income (loss) (24) (7,920) 2,185 (5,759) March 31, 2023 $ (532) $ 16,752 $ (15,987) $ 233 (1) See the following table for details about these reclassifications. Amounts in parentheses indicate debits. The following table presents the reclassifications out of accumulated other comprehensive income for the three months ended March 31, 2024 and 2023, respectively: Details about Accumulated Other Comprehensive Income Components Amounts reclassified from Accumulated Other Comprehensive Loss (Income) (1) Affected line item where Three months ended 2024 2023 Amortization of defined benefit and other postretirement items: Net loss (gain) $ 1 $ (1) Other (expense) income (2) Net prior service cost (credit) 7 (31) Other (expense) income (2) 8 (32) Total before tax (2) 8 Tax (expense) benefit $ 6 $ (24) Net of tax Gains and losses on cash flow hedges: Interest rate caps $ 4,656 $ 698 Interest income (1,164) (172) Tax expense $ 3,492 $ 526 Net of tax Total reclassifications for the period $ 3,498 $ 502 Net of tax (1) Amounts in parentheses indicate debits to profit/loss. (2) These accumulated other comprehensive income (loss) components are components of net periodic pension and other postretirement cost (see Note 14 to these condensed consolidated financial statements for additional details). Treasury Stock Repurchases 2022 Stock Repurchase Program On April 27, 2022, the Board approved a stock repurchase program that authorized the Company to purchase up to $450,000 of the Company’s common stock over the four-year period from the date of approval. Under the plan, the Company is permitted to repurchase shares from time to time for cash in open market transactions or in privately negotiated transactions with an equity sponsor in accordance with applicable federal securities laws, with the Company determining the timing and the amount of any repurchases based on its evaluation of market conditions, share price and other factors. During the three months ended March 31, 2024, the Company did not repurchase any of its common stock pursuant to the stock repurchase program. As of March 31, 2024, $234,592 was available for share repurchases under the program. During the three m onths ended March 31, 2023, in connection with a secondary offering of the Company’s common stock by an equity sponsor in March 2023, the Company repurchased 3,000,000 shares of its common stock sold in the offering from underwriters at a price of $9.95 per share concurrently with the closing of the offering, for a total of $29,850, excluding brokerage commissions and accrued excise tax . Tax Withholdings on Equity Award Vesting In connection with the vesting of restricted stock awards (“RSA” or “RSAs”), restricted stock units (“RSU” or “RSUs”) and performance stock units (“PSU” or “PSUs”), shares of common stock may be delivered to the Company by employees to satisfy withholding tax obligations at the instruction of the employee award holders. These transactions, when they occur, are accounted for as stock repurchases by the Company, with the shares returned to treasury stock at a cost representing the payment by the Company of the tax obligations on behalf of the employees in lieu of shares for the vesting unit. There were 128,801 and 95,269 shares delivered to the Company to cover tax payments for the three months ended March 31, 2024 and 2023, respectively and the fair value of those shares withheld were $1,218 and $866 for the three months ended March 31, 2024 and 2023, respectively.

Goodwill

Goodwill	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	6. Goodwill: The change in the carrying amount of goodwill for the three months ended March 31, 2024 is summarized as follows: Ecoservices Advanced Materials & Catalysts Total Balance as of December 31, 2023 $ 326,589 $ 77,881 $ 404,470 Foreign exchange impact — (218) (218) Balance as of March 31, 2024 $ 326,589 $ 77,663 $ 404,252

Other Operating Expense, Net

Other Operating Expense, Net	3 Months Ended
	Mar. 31, 2024
Other Income and Expenses [Abstract]
Other Operating Expense, Net	7. Other Operating Expense, Net: A summary of other operating expense, net is as follows: Three months ended 2024 2023 Amortization expense $ 2,645 $ 2,637 Transaction and other related costs 58 1,434 Restructuring, integration and business optimization costs 226 1,023 Net loss on asset disposals 648 1,178 Other, net 89 444 $ 3,666 $ 6,716

Inventories, Net

Inventories, Net	3 Months Ended
	Mar. 31, 2024
Inventory Disclosure [Abstract]
Inventories, Net	8. Inventories, Net: Inventories, net are classified and valued as follows: March 31, December 31, Finished products and work in process $ 48,001 $ 41,658 Raw materials 4,502 3,457 $ 52,503 $ 45,115 Valued at lower of cost or market: LIFO basis $ 30,642 $ 24,815 Valued at lower of cost and net realizable value: FIFO or average cost basis 21,861 20,300 $ 52,503 $ 45,115

Investments in Affiliated Compa

Investments in Affiliated Companies	3 Months Ended
	Mar. 31, 2024
Equity Method Investments and Joint Ventures [Abstract]
Investments in Affiliated Companies	9. Investments in Affiliated Companies: The Company accounts for investments in affiliated companies under the equity method. Affiliated companies accounted for on the equity basis as of March 31, 2024 are as follows: Company Country Percent Zeolyst International USA 50% Zeolyst C.V. Netherlands 50% Following is summarized information of the combined investments (1) : Three months ended 2024 2023 Sales $ 56,860 $ 55,897 Gross profit 17,177 10,110 Operating income 6,844 2,399 Net income 7,345 3,647 (1) Summarized information of the combined investments is presented at 100%; the Company’s share of the net assets and net income of affiliates is calculated based on the percent ownership specified in the table above. The Company’s investments in affiliated companies balance as of March 31, 2024 and December 31, 2023 includes net purchase accounting fair value adjustments of $223,014 and $224,614, respectively, related to a prior business combination, consisting primarily of goodwill and intangible assets such as customer relationships, technical know-how and trade names. Consolidated equity in net income from affiliates is net of $1,601 of amortization expense related to purchase accounting fair value adjustments for the three months ended March 31, 2024 and 2023, respectively. The Company had receivables due from affiliates of $3,136 and $3,231 as of March 31, 2024 and December 31, 2023, respectively, which are included in prepaid and other current assets. The Company had no payables from affiliates as of March 31, 2024 and $1,351 as of December 31, 2023, which is included in accrued liabilities. Receivables and payables due from affiliates are generally non-trade. There were no sales to affiliates for the three months ended March 31, 2024 and $1,700 for the three months ended March 31, 2023, respectively. There were no purchases from affiliates for the three months ended March 31, 2024 and immaterial for the three months ended March 31, 2023, respectively.

Property, Plant and Equipment

Property, Plant and Equipment	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	10. Property, Plant and Equipment: A summary of property, plant and equipment, at cost, and related accumulated depreciation is as follows: March 31, December 31, Land $ 96,804 $ 96,833 Buildings and improvements 85,761 84,860 Machinery and equipment 825,370 820,509 Construction in progress 48,936 42,000 1,056,871 1,044,202 Less: accumulated depreciation (484,564) (467,298) $ 572,307 $ 576,904 Depreciation expense was $18,415 and $16,692 for the three months ended March 31, 2024 and 2023, respectively.

Long-term Debt

Long-term Debt	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Long-term Debt	11. Long-term Debt: The summary of long-term debt is as follows: March 31, December 31, Senior Secured Term Loan Facility due June 2028 (the “2021 Term Loan Facility”) $ 875,250 $ 877,500 ABL Facility — — Total debt 875,250 877,500 Original issue discount (5,831) (6,162) Deferred financing costs (3,199) (3,392) Total debt, net of original issue discount and deferred financing costs 866,220 867,946 Less: current portion (9,000) (9,000) Total long-term debt, excluding current portion $ 857,220 $ 858,946 The 2021 Term Loan Facility bears interest at an adjusted term Secured Overnight Financing Rate (“SOFR”) (with a 0.50% minimum floor and a credit spread adjustment of 10 basis points) plus 2.75% per annum (or, depending on the borrower’s first lien net leverage ratio, 2.50%). The interest rate on the 2021 Term Loan Facility was 7.91% as of March 31, 2024. The borrowings under the senior secured asset-based lending revolving credit facility (“ABL Facility”) bears interest at a rate equal to an adjusted term SOFR, which includes a credit spread adjustment of 10 basis points or the base rate plus a margin of between 1.25% to 1.75% or 0.25% to 0.75%, respectively. The interest rate on the ABL Facility was 8.75% as of March 31, 2024. Fair Value of Debt The fair value of a financial instrument is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants. As of March 31, 2024 and December 31, 2023, the fair value of the 2021 Term Loan Facility was $873,062 and $876,403, respectively. The fair value is classified as Level 2 based upon the fair value hierarchy (see Note 4 to these condensed consolidated financial statements for further information on fair value measurements).

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments	12. Financial Instruments: The Company uses interest rate related derivative instruments to manage its exposure to changes in interest rates on its variable-rate debt instruments. The Company does not speculate using derivative instruments. By using derivative financial instruments to hedge exposures to changes in interest rates, the Company exposes itself to credit risk and market risk. Credit risk is the failure of the counterparty to perform under the terms of the derivative contract. When the fair value of a derivative contract is an asset, the counterparty owes the Company, which creates credit risk for the Company. When the fair value of a derivative contract is a liability, the Company owes the counterparty and therefore, the Company is not exposed to the counterparty’s credit risk in those circumstances. The Company minimizes counterparty credit risk in derivative instruments by entering into transactions with high quality counterparties. The derivative instruments entered into by the Company do not contain credit-risk-related contingent features. Market risk is the adverse effect on the value of a derivative instrument that results from a change in interest rates. The market risk associated with the Company’s derivative instruments is managed by establishing and monitoring parameters that limit the types and degree of market risk that may be undertaken. Use of Derivative Financial Instruments to Manage Interest Rate Risk. The Company is exposed to fluctuations in interest rates on its senior secured credit facilities. Changes in interest rates will not affect the market value of such debt but will affect the Company’s interest payments over the term of the loans. Likewise, an increase in interest rates could have a material impact on the Company’s condensed consolidated statements of cash flows. The Company hedges the interest rate fluctuations on debt obligations through interest rate cap agreements. The Company records these agreements at fair value as assets or liabilities in its condensed consolidated balance sheets. As the derivatives are designated and qualify as cash flow hedges, the gains or losses on the interest rate cap agreements are recorded in stockholders’ equity as a component of other comprehensive income, net of tax. Reclassifications of the gains and losses on the interest rate cap agreements into earnings are recorded as part of interest expense in the condensed consolidated statements of income as the Company makes its interest payments on the hedged portion of its senior secured credit facilities. Fair value is determined based on estimated amounts that would be received or paid to terminate the contracts at the reporting date based on quoted market prices. The following table provides a summary of the Company’s interest rate cap agreements: Financial instrument Number of instruments In effect as of March 31, 2024 Current notional amount of instruments in effect Annuitized premium of instruments in effect Interest rate cap 4 3 $ 650,000 $ 24,817 The current notional amounts of the three interest rate cap agreements in effect at March 31, 2024 are $250,000, $250,000 and $150,000. The Company entered into a $250,000 interest rate cap to mitigate interest rate volatility from August 2022 to October 2024, a $250,000 interest rate cap agreement to mitigate interest rate volatility from September 2023 to October 2025 and a $150,000 interest rate cap agreement to mitigate interest rate volatility from August 2023 to July 2024. The $150,000 interest rate cap agreement will increase to $175,000 to mitigate interest rate volatility from August 2024 to July 2026. The cap rate in effect at March 31, 2024 for all agreements in effect was 1.00%. The Company has also entered into a forward starting interest rate cap agreement to mitigate interest volatility from November 2024 to October 2026. In February 2023, the Company amended all existing interest rate cap agreements to replace LIBOR with SOFR as the benchmark interest rate, with all other terms of the agreements remaining the same. This amendment changed the previously annuitized premiums on the existing interest rate cap agreements. The fair values of derivative instruments held as of March 31, 2024 and December 31, 2023, respectively are shown below: Balance sheet location March 31, December 31, Derivative assets Derivatives designated as cash flow hedges: Interest rate caps Prepaid and other current assets $ 13,490 $ 13,419 Interest rate caps Other long-term assets 8,576 5,602 Total derivative assets $ 22,066 $ 19,021 Derivative liabilities Derivatives designated as cash flow hedges: Interest rate caps Other long-term liabilities $ 743 $ 2,496 Total derivative liabilities $ 743 $ 2,496 The following table shows the effect of the Company’s derivative instruments designated as cash flow hedges on AOCI for the three months ended March 31, 2024 and 2023, respectively: Three months ended March 31, 2024 2023 Location of gain (loss) reclassified from AOCI into income Amount of gain (loss) recognized in OCI on derivatives Amount of gain (loss) reclassified from AOCI into income Amount of gain (loss) recognized in OCI on derivatives Amount of gain (loss) reclassified from AOCI into income Interest rate caps Interest (expense) income $ 9,808 $ (4,656) $ (9,605) $ 698 The following table shows the effect of the Company’s cash flow hedge accounting on the condensed consolidated statements of income for the three months ended March 31, 2024 and 2023, respectively: Location and amount of gain (loss) recognized in income on cash flow hedging relationships Three months ended 2024 2023 Total amounts of income and expense line items presented in the statement of income in which the effects of cash flow hedges are recorded in interest (expense) income $ (13,409) $ (9,832) The effects of cash flow hedging: Gain (loss) on cash flow hedging relationships: Interest contracts: Amount of loss reclassified from AOCI into income 4,656 698 The amount of unrealized losses in AOCI related to the Company’s cash flow hedges that is expected to be reclassified to the condensed consolidated statement of income over the next twelve months is $9,199 as of March 31, 2024.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes: The effective income tax rate for the three months ended March 31, 2024 was 49.1%, compared to (180.7)% for the three months ended March 31, 2023. The Company’s effective income tax rate for the three months ended March 31, 2024 was different from the effective tax rate for the three months ended March 31, 2023 primarily due to a stock compensation shortfall recognized discretely in the respective quarters with lower profits before tax in the prior year. The difference between the U.S. federal statutory income tax rate and the Company’s effective income tax rate for the three months ended March 31, 2024 was mainly due to state and local taxes, a discrete shortfall tax expense related to stock compensation and a discrete tax expense associated with the recording of accrued penalties and interest on historical uncertain tax positions. The difference between the U.S. federal statutory income tax rate and the Company’s effective income tax rate for the three months ended March 31, 2023 was mainly due to state and local taxes, a discrete shortfall tax expense related to stock compensation and a discrete tax expense associated with the recording of accrued penalties and interest on historical uncertain tax positions.

Benefit Plans

Benefit Plans	3 Months Ended
	Mar. 31, 2024
Retirement Benefits [Abstract]
Benefit Plans	14. Benefit Plans: The following tables present the components of net periodic expense (benefit) for the Company-sponsored defined benefit pension and postretirement plans, which cover certain employees and retirees located in the U.S. Defined Benefit Pension Plans Three months ended 2024 2023 Interest cost $ 808 $ 871 Expected return on plan assets (827) (837) Net periodic (benefit) expense $ (19) $ 34 Other Postretirement Benefit Plan Three months ended 2024 2023 Interest cost $ 6 $ 6 Amortization of prior service credit (7) (31) Amortization of net gain (1) (1) Net periodic benefit $ (2) $ (26) All components of net periodic (benefit) expense other than service cost are presented within other expense (income), net in the Company’s condensed consolidated statements of income.

Commitments and Contingent Liab

Commitments and Contingent Liabilities	3 Months Ended
	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	15. Commitments and Contingent Liabilities: There is a risk of environmental impact in the Company’s manufacturing operations. The Company’s environmental policies and practices are designed to comply with existing laws and regulations and to minimize the possibility of significant environmental impact. The Company is also subject to various other lawsuits and claims with respect to matters such as governmental regulations, labor and other actions arising out of the normal course of business. All claims that are probable and reasonably estimable have been accrued for in the Company’s condensed consolidated financial statements. When these matters are ultimately concluded and determined, the Company believes that there will be no material adverse effect on its consolidated financial position, results of operations or liquidity.

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2024
Related Party Transactions [Abstract]
Related Party Transactions	16. Related Party Transactions: The Company maintains certain policies and procedures for the review, approval and ratification of related party transactions to ensure that all transactions with selected parties are fair, reasonable and in the Company’s best interests. All significant relationships and transactions are separately identified by management if they meet the definition of a related party or a related party transaction. Related party transactions include transactions that occurred during the year, or are currently proposed, in which the Company was or will be a participant, and for which any related person had or will have a direct or indirect material interest. All related party transactions are reviewed, approved and documented by the appropriate level of the Company’s management in accordance with these policies and procedures. Joint Venture Agreement The Company entered into a joint venture agreement (the “ZI Partnership Agreement”) in 1988 with Shell Catalysts & Technologies, an affiliate of Royal Dutch Shell plc, to form Zeolyst International, a 50/50 joint venture partnership (the “Partnership”). Under the terms of the ZI Partnership Agreement, the Partnership leases certain land used in its Kansas City production facilities from Ecovyst. This lease, which has been recorded as an operating lease, provided for rental payments to the Company of $77 for the three months ended March 31, 2024 and 2023, respectively. The terms of this lease are evergreen as long as the ZI Partnership Agreement is in place. The Partnership had no sales to the Company for the three months ended March 31, 2024 and 2023, respectively. The Partnership purchases certain of its raw materials from the Company and is charged for various manufacturing costs incurred at the Company’s Kansas City production facility. The amount of these costs charged to the Partnership were $4,034 and $5,841 for the three months ended March 31, 2024 and 2023, respectively. Certain administrative, marketing, engineering, management-related, and research and development services are provided to the Partnership by the Company. The Partnership was charged $4,300 and $3,634 for the three months ended March 31, 2024 and 2023, respectively, for these services. In addition, the Partnership was charged certain product demonstration costs of $357 and $500 for the three months ended March 31, 2024 and 2023, respectively. These charges to the Partnership are recorded as reductions in either cost of goods sold or selling, general and administrative expenses in the consolidated statements of income, depending on the nature of the expenditures. The Company had an accounts receivable from the Partnership of $3,115 and $3,164 as of March 31, 2024 and December 31, 2023, respectively. There were no accounts payable with the Partnership as of March 31, 2024 and December 31, 2023, respectively. Other From time to time, the Company makes sales to and purchases raw materials from portfolio companies of funds that are affiliated with INEOS Capital Partners. The Company had sales of $1,249 and $595 to companies affiliated with INEOS Capital Partners for the three months ended March 31, 2024 and 2023, respectively. There were no purchases of raw materials from companies affiliated with INEOS Capital Partners for the three months ended March 31, 2024 and immaterial for the three months ended March 31, 2023.

Reportable Segments

Reportable Segments	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Reportable Segments	17. Reportable Segments: Summarized financial information for the Company’s reportable segments is shown in the following table: Three months ended 2024 2023 Sales: Ecoservices $ 141,602 $ 137,740 Advanced Materials & Catalysts (1) 18,935 23,134 Total $ 160,537 $ 160,874 Adjusted EBITDA: (2) Ecoservices $ 41,494 $ 36,787 Advanced Materials & Catalysts (3) 11,129 12,989 Adjusted EBITDA from reportable segments $ 52,623 $ 49,776 (1) Excludes the Company’s proportionate share of sales from the Zeolyst Joint Venture accounted for using the equity method (see Note 9 to these condensed consolidated financial statements for further information). The proportionate share of sales excluded is $23,481 and $22,074 for the three months ended March 31, 2024 and 2023, respectively. (2) The Company defines Adjusted EBITDA as EBITDA adjusted for certain items as noted in the reconciliation below. Management evaluates the performance of its segments and allocates resources based on several factors, of which the primary measure is Adjusted EBITDA. Adjusted EBITDA should not be considered as an alternative to net income as an indicator of the Company’s operating performance. Adjusted EBITDA as defined by the Company may not be comparable with EBITDA or Adjusted EBITDA as defined by other companies. (3) The Adjusted EBITDA for the Company’s Advanced Materials & Catalysts segment includes the Company’s 50% portion of the Adjusted EBITDA from the Zeolyst Joint Venture. The Adjusted EBITDA from the Zeolyst Joint Venture included in the Advanced Materials & Catalysts segment was $6,927 for the three months ended March 31, 2024, which includes $2,072 of equity in net income plus $1,601 of amortization of investment in affiliate step-up and $3,254 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the Advanced Materials & Catalysts segment was $5,436 for the three months ended March 31, 2023, which includes $226 of equity in net income plus $1,601 of amortization of investment in affiliate step-up and $3,609 of joint venture depreciation, amortization and interest. A reconciliation of income (loss) before income taxes to Adjusted EBITDA is as follows: Three months ended 2024 2023 Reconciliation of income (loss) before income taxes to Adjusted EBITDA from reportable segments Income (loss) before income taxes $ 2,400 $ (524) Interest expense, net 13,409 9,832 Depreciation and amortization 21,933 20,197 Unallocated corporate expenses 7,081 6,926 Joint venture depreciation, amortization and interest 3,254 3,609 Amortization of investment in affiliate step-up 1,601 1,601 Net loss on asset disposals 648 1,178 Foreign exchange loss (gain) 178 (738) LIFO (benefit) expense (1,124) 1,399 Transaction and other related costs 58 1,434 Equity-based compensation 3,680 4,068 Restructuring, integration and business optimization expenses 226 1,023 Other (721) (229) Adjusted EBITDA from reportable segments $ 52,623 $ 49,776

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	18. Stock-Based Compensation: The Company has an equity incentive plan under which it grants common stock awards to employees, directors and affiliates of the Company. At March 31, 2024, 7,994,600 shares of common stock were available for issuance under the plan. The Company historically has settled these awards through the issuance of new shares. RSU During the three months ended March 31, 2024, the Company granted 1,108,063 RSUs under its equity incentive plan. Each RSU provides the recipient with the right to receive a share of common stock subject to graded vesting terms based on service, which for the awards granted during the three months ended March 31, 2024, generally requires approximately one year of service for members of the Company’s board of directors and approximately three years of service for employees. The value of the RSUs granted during the three months ended March 31, 2024 was based on the average of the high and low trading prices of the Company’s common stock on the NYSE on the preceding trading day, in accordance with the Company’s policy for valuing such awards. Compensation expense related to the RSUs is recognized on a straight-line basis over the respective vesting period. PSU 2024 Grants During the three months ended March 31, 2024, the Company granted 535,629 PSUs (at target) under its equity incentive plan. The PSUs granted during the three months ended March 31, 2024 provide the recipients with the right to receive shares of common stock dependent on 50% of a Company-specific financial performance target and 50% on the relative increase in the total shareholder return (“TSR”) goal (“the Performance measures”). The Performance measures are measured independently of each other, but achievement of both metrics is measured on the same three-year performance period from January 1, 2024 through December 31, 2026 (“Performance period”). Depending on the Company’s performance relative to the Performance measures, each PSU award recipient is eligible to receive a percentage of the target number of shares granted to the recipient, ranging from 50% to 200%. The PSUs, to the extent earned, will vest on the date the Compensation Committee of the Company’s Board of Directors (“Compensation Committee”) certifies the achievement of the Performance measures for the Performance period, which will occur subsequent to the end of the Performance period and after the Company files its annual consolidated financial statements for the year ending December 31, 2026. Achievement of the Company-specific financial performance target is measured based on the actual three-year cumulative results across the Performance period. The TSR goal is based on the Company’s actual TSR performance against companies in the S&P 1500 Specialty Chemicals Index over the Performance period. The TSR goal, which determines how much of the 50% of the PSUs granted during 2024 may be earned, is considered a market condition as opposed to a vesting condition. Because a market condition is not considered a vesting condition, it is reflected in the grant date fair value of the award and the associated compensation cost based on the fair value of the award is recognized over the Performance period, regardless of whether the Company actually achieves the market condition or the level of achievement, as long as service is provided by the recipient. The Company used a Monte Carlo simulation to estimate the $11.64 weighted average fair value of the awards granted subject to the TSR goal during the three months ended March 31, 2024, with the following weighted average assumptions: Expected dividend yield — % Risk-free interest rate 4.09 % Expected volatility 39.45 % Expected term (in years) 2.95 2021 Grants In February 2024, the Compensation Committee certified the achievement of the performance metrics for the three-year period ended December 31, 2023, related to the PSUs granted during the year ended December 31, 2021. The PSUs granted during the year ended December 31, 2021 provide the recipients with the right to receive shares of common stock dependent on the achievement of a TSR goal, and are generally subject to the provision of service through the vesting date of the award. The TSR goal was based on the Company’s actual TSR percentage increase over the performance period. The awards vested during the three months ended March 31, 2024 with no percentage of the TSR goal earned. Award Activity The following table summarizes the activity for the Company’s RSUs and PSUs for the three months ended March 31, 2024: Restricted Stock Units Performance Stock Units Number of Weighted average grant date fair value (per share) Number of Weighted average grant date fair value (per share) Nonvested as of December 31, 2023 1,962,828 $ 10.55 959,217 (1) $ 11.84 Granted 1,108,063 $ 8.82 535,629 $ 10.23 Vested (996,148) $ 10.36 — $ — Forfeited (19,197) $ 11.10 (126,497) $ 12.99 Nonvested as of March 31, 2024 2,055,546 $ 9.35 1,368,349 (1) $ 11.10 (1) Based on target. During the three months ended March 31, 2024, the Company also granted 4,540 of RSAs with a weighted average grant date fair value of $8.81 per share that immediately vested. Cash proceeds received by the Company from the exercise of stock options were not material for the three months ended March 31, 2024. Stock-Based Compensation Expense For the three months ended March 31, 2024 and 2023, stock-based compensation expense for the Company was $3,680 and $4,068, respectively. The associated income tax benefit based on the applicable statutory rate recognized in the condensed consolidated statements of income for the three months ended March 31, 2024 and 2023 was $902 and $973, respectively. As of March 31, 2024, unrecognized compensation cost was $16,857 for RSUs and $10,670 for PSUs, and the weighted-average period over which these costs are expected to be recognized at March 31, 2024 was 2.01 years for the RSUs and 2.36 years for the PSUs.

Earnings per Share

Earnings per Share	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Earnings per Share	19. Earnings per Share: Basic earnings per share is calculated as income available to common stockholders, divided by the weighted average number of common shares outstanding during the period. The weighted average number of common shares outstanding during the period for the computation of basic earnings per share excludes RSAs that have legally been issued but are nonvested during the period, as the sale of these shares is prohibited pending satisfaction of certain vesting conditions by the award recipients in order to earn the rights to the shares. Diluted earnings per share is calculated as income available to common stockholders, divided by the weighted average number of common and potential common shares outstanding during the period, if dilutive. Potential common shares reflect (1) unvested RSAs and RSUs with service vesting conditions, (2) PSUs with vesting conditions considered probable of achievement and (3) options to purchase common stock, all of which have been included in the diluted earnings per share calculation using the treasury stock method. The reconciliation from basic to diluted weighted average shares outstanding is as follows: Three months ended 2024 2023 Weighted average shares outstanding – Basic 116,955,043 122,178,867 Dilutive effect of unvested common shares and RSUs with service conditions, PSUs considered probable of vesting and assumed stock option exercises and conversions 496,106 — Weighted average shares outstanding – Diluted 117,451,149 122,178,867 Basic and diluted income per share are calculated as follows: Three months ended 2024 2023 Numerator: Net income (loss) $ 1,221 $ (1,471) Denominator: Weighted average shares outstanding – Basic 116,955,043 122,178,867 Weighted average shares outstanding – Diluted 117,451,149 122,178,867 Net income (loss) per share: Basic income (loss) per share $ 0.01 $ (0.01) Diluted income (loss) per share $ 0.01 $ (0.01) The table below presents the details of the Company’s weighted average equity-based awards outstanding during each respective period that were excluded from the calculation of diluted earnings per share: Three months ended 2024 2023 RSAs with performance only targets not achieved — 200,096 Stock options with performance only targets not achieved — 208,968 Anti-dilutive RSUs and PSUs (1) 558,989 432,308 Anti-dilutive stock options (1) 367,100 695,777 (1) Does not include 1,044,098 of RSUs and PSUs, and 352,771 of stock options, for the three months ended March 31, 2023 due to the net loss attributable to Ecovyst Inc. for the period. RSAs and stock options with performance only vesting conditions were not included in the dilution calculation, as the performance targets have not been achieved nor were probable of achievement as of the end of the respective periods. These awards and stock options were canceled on March 7, 2023 (see Note 18 to these condensed consolidated financial statements for additional information). Certain stock options to purchase shares of common stock were excluded from the computation of diluted earnings per share for the respective periods because the options’ exercise price was greater than the average market price of the common shares. These stock options and anti-dilutive awards are not included in the dilution calculation, as their inclusion would have the effect of increasing diluted income per share or reducing diluted loss per share.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	3 Months Ended
	Mar. 31, 2024
Supplemental Cash Flow Elements [Abstract]
Supplemental Cash Flow Information	20. Supplemental Cash Flow Information: The following table presents supplemental cash flow information for the Company: Three months ended 2024 2023 Cash paid during the period for: Income taxes, net of refunds $ 3,608 $ 136 Interest (1) 12,569 15,185 Non-cash investing activity: Capital expenditures acquired on account but unpaid as of the period end 713 650 Right-of-use assets obtained in exchange for new lease liabilities (non-cash): Operating leases 2,131 1,621 (1) Cash paid for interest is shown net of capitalized interest and includes the cash received or paid on the Company’s interest rate cap agreements designated as cash flow hedges for the periods presented (see Note 12 to these condensed consolidated financial statements for details).

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2024
Subsequent Events [Abstract]
Subsequent Events	21. Subsequent Events: The Company has evaluated subsequent events since the balance sheet date and determined that there are no additional items to disclose.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net income (loss)	$ 1,221	$ (1,471)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Background and Basis of Prese_2

Background and Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The condensed consolidated financial statements included herein are unaudited. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) have been condensed or omitted pursuant to such rules and regulations for interim reporting. In the opinion of management, all adjustments of a normal and recurring nature necessary to state fairly the financial position and results of operations have been included. The results of operations are not necessarily indicative of the expected results for the full year. The accompanying unaudited condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023.
Accounting Standards Not Yet Adopted	Accounting Standards Not Yet Adopted In November 2023, the Financial Accounting Standards Board (“FASB”) issued guidance to improve the disclosures related to public business entities reportable segments. This new guidance requires entities to provide information regarding significant segment expenses, especially those segment expenses that are regularly reported to the Company’s chief operating decision maker (the Company’s Chief Executive Officer), or CODM. The guidance also require public entities to disclose the nature, type and amounts of other segment items by reportable segment. Public business entities will also have to report all annual disclosures about segments profits or losses that are required by ASC 280 on an interim basis, including the significant segment expenses and other segment items. The new guidance is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. The disclosure will be implemented as required for the fiscal year ended December 31, 2024. The Company is currently evaluating the impact of this guidance. In December 2023, FASB issued guidance to improve disclosures related to incomes taxes. This new guidance requires public business entities to disaggregate information on the effective tax rate reconciliation and income taxes paid to provide greater transparency. Public business entities will be required to provide additional information in specified categories related to effective tax rate reconciliation in tabular form and provide income taxes paid by jurisdictions, with further disaggregation needed if amounts exceed 5% of the total. The new guidance is effective for fiscal years beginning after December 15, 2024. The disclosure will be implemented as required for the fiscal year ended December 31, 2025. The Company is currently evaluating the impact of this guidance. In October 2023, FASB issued guidance to amend either presentation or disclosure requirements related to fourteen subtopics in the FASB Accounting Standards Codification, that are currently in the SEC Regulation S-X or Regulation S-K. The new guidance was issued in response to the SEC’s ruling on disclosure simplification. For entities subject to existing SEC disclosure requirements, the effective date of each amendment of the topics will be the date that the SEC removes the related disclosure from Regulation S-X or Regulation S-K. The guidance must be applied prospectively, with no early adoption permitted for entities subject to those existing SEC disclosures. The Company is currently evaluating the impact of the new guidance as it pertains to the fourteen subtopics that would impact the business and will apply prospectively once in effect. In August 2023, the FASB issued guidance for entities that meet the definition of a joint venture or a corporate joint venture, to adopt a new basis of accounting upon the formation of the joint venture. The new guidance requires the initial measurement of contributed net assets and liabilities at fair value on the formation date, recognition of goodwill for the difference between the fair value of the joint venture’s equity and net assets, and disclosures about the nature and financial impact of the transaction. The new guidance requires prospective application and is effective for all joint ventures that are formed on or after January 1, 2025, with early adoption permitted. Joint ventures that formed before January 1, 2025 may elect to retrospectively apply the new guidance. The Company will apply the guidance to any new joint ventures formed after the effective date.
Derivative contracts	Derivative contracts Derivative assets and liabilities can be exchange-traded or traded over-the-counter (“OTC”). The Company generally values exchange-traded derivatives using models that calibrate to market transactions and eliminate timing differences between the closing price of the exchange-traded derivatives and their underlying instruments. OTC derivatives are valued using market transactions and other market evidence whenever possible, including market-based inputs to models, model calibration to market transactions, broker or dealer quotations or alternative pricing sources with reasonable levels of price transparency. When models are used, the selection of a particular model to value an OTC derivative depends on the contractual terms of, and specific risks inherent in, the instrument as well as the availability of pricing information in the market. The Company generally uses similar models to value similar instruments. Valuation models require a variety of inputs, including contractual terms, market prices and rates, forward curves, measures of volatility, and correlations of such inputs. For OTC derivatives that trade in liquid markets, such as forward contracts, swaps and options, model inputs can generally be corroborated by observable market data by correlation or other means, and model selection does not involve significant management judgment. As of March 31, 2024, th e Company had interest rate c aps th at were fair valued using Level 2 inputs. In addition, the Company applies a credit valuation adjustment to reflect credit risk which is calculated based on credit default swaps. To the extent that the Company’s net exposure under a specific master agreement is an asset, the Company utilizes the counterparty’s default swap rate. If the net exposure under a specific master agreement is a liability, the Company utilizes a default swap rate comparable to Ecovyst. The credit valuation adjustment is added to the discounted fair value to reflect the exit price that a market participant would be willing to receive to assume the Company’s liabilities or that a market participant would be willing to pay for the Company’s assets.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	3 Months Ended
	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The Company’s portfolio of products is integrated into a variety of end uses, which are described in the table below. Key End Uses Key Products Clean fuels, emission control & other • Refining hydrocracking catalysts • Emission control catalysts • Catalyst supports used in production of sustainable fuels such as renewable diesel • Catalysts used in production of sustainable aviation fuels • Catalyst activation • Aluminum sulfate solution • Ammonium bisulfite solution Polyethylene, polymers & engineered plastics • Catalysts for high-density polyethylene and chemicals syntheses • Antiblock for film packaging • Catalyst for advanced recycling Regeneration and treatment services • Sulfuric acid regeneration services • Treatment services Industrial, mining & automotive • Sulfuric acid for mining • Sulfur derivatives for industrial production • Sulfuric derivatives for nylon production The following tables disaggregate the Company’s sales, by segment and end uses, for the three months ended March 31, 2024 and 2023, respectively: Three months ended March 31, 2024 Ecoservices Advanced Materials & Catalyst (2) Total Clean fuels, emission control & other $ 7,389 $ — $ 7,389 Polyethylene, polymers & engineered plastics — 18,935 18,935 Regeneration and treatment services (1) 83,319 — 83,319 Industrial, mining & automotive 50,894 — 50,894 Total segment sales $ 141,602 $ 18,935 $ 160,537 Three months ended March 31, 2023 Ecoservices Advanced Materials & Catalyst (2) Total Clean fuels, emission control & other $ 4,740 $ — $ 4,740 Polyethylene, polymers & engineered plastics — 23,134 23,134 Regeneration and treatment services (1) 88,344 — 88,344 Industrial, mining & automotive 44,656 — 44,656 Total segment sales $ 137,740 $ 23,134 $ 160,874 (1) As described in Note 1 to these condensed consolidated financial statements, the Company experiences seasonal s ales fluctuations to customers in the regeneration services product group. (2) Excludes the Company’s proportionate share of sales from the Zeolyst International and Zeolyst C.V. joint ventures (collectively, the “Zeolyst Joint Venture”) accounted for using the equity method (see Note 9 to these condensed consolidated financial statements for further information).

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measured on Recurring Basis	The following tables present information about the Company’s assets and liabilities that were measured at fair value on a recurring basis as of March 31, 2024 and December 31, 2023, and indicates the fair value hierarchy of the valuation techniques the Company utilized to determine such fair value. March 31, Quoted Prices in Significant Other Significant Derivative assets: Interest rate caps (Note 12) $ 22,066 $ — $ 22,066 $ — Derivative liabilities: Interest rate caps (Note 12) $ 743 $ — $ 743 $ — December 31, Quoted Prices in Significant Other Significant Derivative assets: Interest rate caps (Note 12) $ 19,021 $ — $ 19,021 $ — Derivative liabilities: Interest rate caps (Note 12) $ 2,496 $ — $ 2,496 $ —

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Pre-tax and After-tax Components of Other Comprehensive Income (Loss)	The following tables present the tax effects of each component of other comprehensive income (loss) for the three months ended March 31, 2024 and 2023, respectively: Three months ended March 31, 2024 2023 Pre-tax Tax benefit/ After-tax amount Pre-tax Tax benefit After-tax amount Defined benefit and other postretirement plans: Net loss $ (1) $ — $ (1) $ (1) $ — $ (1) Net prior service cost (7) 2 (5) (31) 8 (23) Benefit plans, net (8) 2 (6) (32) 8 (24) Net gain (loss) from hedging activities 5,152 (1,288) 3,864 (10,303) 2,383 (7,920) Foreign currency translation (1,684) — (1,684) 2,185 — 2,185 Other comprehensive income (loss) $ 3,460 $ (1,286) $ 2,174 $ (8,150) $ 2,391 $ (5,759) The following tables present the changes in accumulated other comprehensive income, net of tax, by component for the three months ended March 31, 2024 and 2023, respectively: Defined benefit Net gain (loss) Foreign Total December 31, 2023 $ 612 $ 12,546 $ (14,116) $ (958) Other comprehensive income (loss) before reclassifications — 7,356 (1,684) 5,672 Amounts reclassified from accumulated other comprehensive loss (1) (6) (3,492) — (3,498) Net current period other comprehensive income (loss) (6) 3,864 (1,684) 2,174 March 31, 2024 $ 606 $ 16,410 $ (15,800) $ 1,216 December 31, 2022 $ (508) $ 24,672 $ (18,172) $ 5,992 Other comprehensive income (loss) before reclassifications (48) (7,394) 2,185 (5,257) Amounts reclassified from accumulated other comprehensive income (loss) (1) 24 (526) — (502) Net current period other comprehensive income (loss) (24) (7,920) 2,185 (5,759) March 31, 2023 $ (532) $ 16,752 $ (15,987) $ 233 (1) See the following table for details about these reclassifications. Amounts in parentheses indicate debits.
Reclassifications out of Accumulated Other Comprehensive Income	The following table presents the reclassifications out of accumulated other comprehensive income for the three months ended March 31, 2024 and 2023, respectively: Details about Accumulated Other Comprehensive Income Components Amounts reclassified from Accumulated Other Comprehensive Loss (Income) (1) Affected line item where Three months ended 2024 2023 Amortization of defined benefit and other postretirement items: Net loss (gain) $ 1 $ (1) Other (expense) income (2) Net prior service cost (credit) 7 (31) Other (expense) income (2) 8 (32) Total before tax (2) 8 Tax (expense) benefit $ 6 $ (24) Net of tax Gains and losses on cash flow hedges: Interest rate caps $ 4,656 $ 698 Interest income (1,164) (172) Tax expense $ 3,492 $ 526 Net of tax Total reclassifications for the period $ 3,498 $ 502 Net of tax (1) Amounts in parentheses indicate debits to profit/loss. (2) These accumulated other comprehensive income (loss) components are components of net periodic pension and other postretirement cost (see Note 14 to these condensed consolidated financial statements for additional details).

Goodwill (Tables)

Goodwill (Tables)	3 Months Ended
	Mar. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Change in Carrying Amount of Goodwill	The change in the carrying amount of goodwill for the three months ended March 31, 2024 is summarized as follows: Ecoservices Advanced Materials & Catalysts Total Balance as of December 31, 2023 $ 326,589 $ 77,881 $ 404,470 Foreign exchange impact — (218) (218) Balance as of March 31, 2024 $ 326,589 $ 77,663 $ 404,252

Other Operating Expense, Net (T

Other Operating Expense, Net (Tables)	3 Months Ended
	Mar. 31, 2024
Other Income and Expenses [Abstract]
Summary of Other Operating Expense, Net	A summary of other operating expense, net is as follows: Three months ended 2024 2023 Amortization expense $ 2,645 $ 2,637 Transaction and other related costs 58 1,434 Restructuring, integration and business optimization costs 226 1,023 Net loss on asset disposals 648 1,178 Other, net 89 444 $ 3,666 $ 6,716

Inventories, Net (Tables)

Inventories, Net (Tables)	3 Months Ended
	Mar. 31, 2024
Inventory Disclosure [Abstract]
Inventories, Net	Inventories, net are classified and valued as follows: March 31, December 31, Finished products and work in process $ 48,001 $ 41,658 Raw materials 4,502 3,457 $ 52,503 $ 45,115 Valued at lower of cost or market: LIFO basis $ 30,642 $ 24,815 Valued at lower of cost and net realizable value: FIFO or average cost basis 21,861 20,300 $ 52,503 $ 45,115

Investments in Affiliated Com_2

Investments in Affiliated Companies (Tables)	3 Months Ended
	Mar. 31, 2024
Equity Method Investments and Joint Ventures [Abstract]
Ownership Percentage and Summarized Income Statement	Affiliated companies accounted for on the equity basis as of March 31, 2024 are as follows: Company Country Percent Zeolyst International USA 50% Zeolyst C.V. Netherlands 50% Following is summarized information of the combined investments (1) : Three months ended 2024 2023 Sales $ 56,860 $ 55,897 Gross profit 17,177 10,110 Operating income 6,844 2,399 Net income 7,345 3,647 (1) Summarized information of the combined investments is presented at 100%; the Company’s share of the net assets and net income of affiliates is calculated based on the percent ownership specified in the table above.

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	3 Months Ended
	Mar. 31, 2024
Property, Plant and Equipment [Abstract]
Summary of Property, Plant and Equipment	A summary of property, plant and equipment, at cost, and related accumulated depreciation is as follows: March 31, December 31, Land $ 96,804 $ 96,833 Buildings and improvements 85,761 84,860 Machinery and equipment 825,370 820,509 Construction in progress 48,936 42,000 1,056,871 1,044,202 Less: accumulated depreciation (484,564) (467,298) $ 572,307 $ 576,904

Long-term Debt (Tables)

Long-term Debt (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Summary of Long-Term Debt	The summary of long-term debt is as follows: March 31, December 31, Senior Secured Term Loan Facility due June 2028 (the “2021 Term Loan Facility”) $ 875,250 $ 877,500 ABL Facility — — Total debt 875,250 877,500 Original issue discount (5,831) (6,162) Deferred financing costs (3,199) (3,392) Total debt, net of original issue discount and deferred financing costs 866,220 867,946 Less: current portion (9,000) (9,000) Total long-term debt, excluding current portion $ 857,220 $ 858,946

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Interest Rate Cap Agreements	The following table provides a summary of the Company’s interest rate cap agreements: Financial instrument Number of instruments In effect as of March 31, 2024 Current notional amount of instruments in effect Annuitized premium of instruments in effect Interest rate cap 4 3 $ 650,000 $ 24,817
Fair Values of Derivative Instruments Held	The fair values of derivative instruments held as of March 31, 2024 and December 31, 2023, respectively are shown below: Balance sheet location March 31, December 31, Derivative assets Derivatives designated as cash flow hedges: Interest rate caps Prepaid and other current assets $ 13,490 $ 13,419 Interest rate caps Other long-term assets 8,576 5,602 Total derivative assets $ 22,066 $ 19,021 Derivative liabilities Derivatives designated as cash flow hedges: Interest rate caps Other long-term liabilities $ 743 $ 2,496 Total derivative liabilities $ 743 $ 2,496
Effect of Derivative Instruments Designated as Hedges on Other Comprehensive Income	The following table shows the effect of the Company’s derivative instruments designated as cash flow hedges on AOCI for the three months ended March 31, 2024 and 2023, respectively: Three months ended March 31, 2024 2023 Location of gain (loss) reclassified from AOCI into income Amount of gain (loss) recognized in OCI on derivatives Amount of gain (loss) reclassified from AOCI into income Amount of gain (loss) recognized in OCI on derivatives Amount of gain (loss) reclassified from AOCI into income Interest rate caps Interest (expense) income $ 9,808 $ (4,656) $ (9,605) $ 698
Cash Flow Hedge Impact on Income Statement	The following table shows the effect of the Company’s cash flow hedge accounting on the condensed consolidated statements of income for the three months ended March 31, 2024 and 2023, respectively: Location and amount of gain (loss) recognized in income on cash flow hedging relationships Three months ended 2024 2023 Total amounts of income and expense line items presented in the statement of income in which the effects of cash flow hedges are recorded in interest (expense) income $ (13,409) $ (9,832) The effects of cash flow hedging: Gain (loss) on cash flow hedging relationships: Interest contracts: Amount of loss reclassified from AOCI into income 4,656 698

Benefit Plans (Tables)

Benefit Plans (Tables)	3 Months Ended
	Mar. 31, 2024
Retirement Benefits [Abstract]
Components of Net Periodic Expense (Benefit)	Defined Benefit Pension Plans Three months ended 2024 2023 Interest cost $ 808 $ 871 Expected return on plan assets (827) (837) Net periodic (benefit) expense $ (19) $ 34 Other Postretirement Benefit Plan Three months ended 2024 2023 Interest cost $ 6 $ 6 Amortization of prior service credit (7) (31) Amortization of net gain (1) (1) Net periodic benefit $ (2) $ (26)

Reportable Segments (Tables)

Reportable Segments (Tables)	3 Months Ended
	Mar. 31, 2024
Segment Reporting [Abstract]
Summary Financial Information by Reportable Segment	Summarized financial information for the Company’s reportable segments is shown in the following table: Three months ended 2024 2023 Sales: Ecoservices $ 141,602 $ 137,740 Advanced Materials & Catalysts (1) 18,935 23,134 Total $ 160,537 $ 160,874 Adjusted EBITDA: (2) Ecoservices $ 41,494 $ 36,787 Advanced Materials & Catalysts (3) 11,129 12,989 Adjusted EBITDA from reportable segments $ 52,623 $ 49,776 (1) Excludes the Company’s proportionate share of sales from the Zeolyst Joint Venture accounted for using the equity method (see Note 9 to these condensed consolidated financial statements for further information). The proportionate share of sales excluded is $23,481 and $22,074 for the three months ended March 31, 2024 and 2023, respectively. (2) The Company defines Adjusted EBITDA as EBITDA adjusted for certain items as noted in the reconciliation below. Management evaluates the performance of its segments and allocates resources based on several factors, of which the primary measure is Adjusted EBITDA. Adjusted EBITDA should not be considered as an alternative to net income as an indicator of the Company’s operating performance. Adjusted EBITDA as defined by the Company may not be comparable with EBITDA or Adjusted EBITDA as defined by other companies. (3) The Adjusted EBITDA for the Company’s Advanced Materials & Catalysts segment includes the Company’s 50% portion of the Adjusted EBITDA from the Zeolyst Joint Venture. The Adjusted EBITDA from the Zeolyst Joint Venture included in the Advanced Materials & Catalysts segment was $6,927 for the three months ended March 31, 2024, which includes $2,072 of equity in net income plus $1,601 of amortization of investment in affiliate step-up and $3,254 of joint venture depreciation, amortization and interest. The Adjusted EBITDA from the Zeolyst Joint Venture included in the Advanced Materials & Catalysts segment was $5,436 for the three months ended March 31, 2023, which includes $226 of equity in net income plus $1,601 of amortization of investment in affiliate step-up and $3,609 of joint venture depreciation, amortization and interest.
Reconciliation of Net Income to Segment Adjusted EBITDA	A reconciliation of income (loss) before income taxes to Adjusted EBITDA is as follows: Three months ended 2024 2023 Reconciliation of income (loss) before income taxes to Adjusted EBITDA from reportable segments Income (loss) before income taxes $ 2,400 $ (524) Interest expense, net 13,409 9,832 Depreciation and amortization 21,933 20,197 Unallocated corporate expenses 7,081 6,926 Joint venture depreciation, amortization and interest 3,254 3,609 Amortization of investment in affiliate step-up 1,601 1,601 Net loss on asset disposals 648 1,178 Foreign exchange loss (gain) 178 (738) LIFO (benefit) expense (1,124) 1,399 Transaction and other related costs 58 1,434 Equity-based compensation 3,680 4,068 Restructuring, integration and business optimization expenses 226 1,023 Other (721) (229) Adjusted EBITDA from reportable segments $ 52,623 $ 49,776

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]
Valuation Assumptions	The Company used a Monte Carlo simulation to estimate the $11.64 weighted average fair value of the awards granted subject to the TSR goal during the three months ended March 31, 2024, with the following weighted average assumptions: Expected dividend yield — % Risk-free interest rate 4.09 % Expected volatility 39.45 % Expected term (in years) 2.95
Activity of Restricted Stock Units	The following table summarizes the activity for the Company’s RSUs and PSUs for the three months ended March 31, 2024: Restricted Stock Units Performance Stock Units Number of Weighted average grant date fair value (per share) Number of Weighted average grant date fair value (per share) Nonvested as of December 31, 2023 1,962,828 $ 10.55 959,217 (1) $ 11.84 Granted 1,108,063 $ 8.82 535,629 $ 10.23 Vested (996,148) $ 10.36 — $ — Forfeited (19,197) $ 11.10 (126,497) $ 12.99 Nonvested as of March 31, 2024 2,055,546 $ 9.35 1,368,349 (1) $ 11.10 (1) Based on target.
Activity of Performance Stock Units	The following table summarizes the activity for the Company’s RSUs and PSUs for the three months ended March 31, 2024: Restricted Stock Units Performance Stock Units Number of Weighted average grant date fair value (per share) Number of Weighted average grant date fair value (per share) Nonvested as of December 31, 2023 1,962,828 $ 10.55 959,217 (1) $ 11.84 Granted 1,108,063 $ 8.82 535,629 $ 10.23 Vested (996,148) $ 10.36 — $ — Forfeited (19,197) $ 11.10 (126,497) $ 12.99 Nonvested as of March 31, 2024 2,055,546 $ 9.35 1,368,349 (1) $ 11.10 (1) Based on target.

Earnings per Share (Tables)

Earnings per Share (Tables)	3 Months Ended
	Mar. 31, 2024
Earnings Per Share [Abstract]
Reconciliation from Basic to Diluted Weighted Average Shares Outstanding	The reconciliation from basic to diluted weighted average shares outstanding is as follows: Three months ended 2024 2023 Weighted average shares outstanding – Basic 116,955,043 122,178,867 Dilutive effect of unvested common shares and RSUs with service conditions, PSUs considered probable of vesting and assumed stock option exercises and conversions 496,106 — Weighted average shares outstanding – Diluted 117,451,149 122,178,867
Calculation of Basic and Diluted Earnings per Share	Basic and diluted income per share are calculated as follows: Three months ended 2024 2023 Numerator: Net income (loss) $ 1,221 $ (1,471) Denominator: Weighted average shares outstanding – Basic 116,955,043 122,178,867 Weighted average shares outstanding – Diluted 117,451,149 122,178,867 Net income (loss) per share: Basic income (loss) per share $ 0.01 $ (0.01) Diluted income (loss) per share $ 0.01 $ (0.01)
Anti-dilutive Shares	The table below presents the details of the Company’s weighted average equity-based awards outstanding during each respective period that were excluded from the calculation of diluted earnings per share: Three months ended 2024 2023 RSAs with performance only targets not achieved — 200,096 Stock options with performance only targets not achieved — 208,968 Anti-dilutive RSUs and PSUs (1) 558,989 432,308 Anti-dilutive stock options (1) 367,100 695,777 (1) Does not include 1,044,098 of RSUs and PSUs, and 352,771 of stock options, for the three months ended March 31, 2023 due to the net loss attributable to Ecovyst Inc. for the period.

Supplemental Cash Flow Inform_2

Supplemental Cash Flow Information (Tables)	3 Months Ended
	Mar. 31, 2024
Supplemental Cash Flow Elements [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	The following table presents supplemental cash flow information for the Company: Three months ended 2024 2023 Cash paid during the period for: Income taxes, net of refunds $ 3,608 $ 136 Interest (1) 12,569 15,185 Non-cash investing activity: Capital expenditures acquired on account but unpaid as of the period end 713 650 Right-of-use assets obtained in exchange for new lease liabilities (non-cash): Operating leases 2,131 1,621 (1) Cash paid for interest is shown net of capitalized interest and includes the cash received or paid on the Company’s interest rate cap agreements designated as cash flow hedges for the periods presented (see Note 12 to these condensed consolidated financial statements for details).

Background and Basis of Prese_3

Background and Basis of Presentation - (Details)	3 Months Ended
	Mar. 31, 2024 reporting_unit
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of reporting units	2

Revenue from Contracts with C_3

Revenue from Contracts with Customers - (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	$ 160,537	$ 160,874
Clean fuels, emission control & other
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	7,389	4,740
Polyethylene, polymers & engineered plastics
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	18,935	23,134
Regeneration and treatment services
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	83,319	88,344
Industrial, mining & automotive
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	50,894	44,656
Ecoservices
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	141,602	137,740
Ecoservices | Clean fuels, emission control & other
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	7,389	4,740
Ecoservices | Polyethylene, polymers & engineered plastics
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Ecoservices | Regeneration and treatment services
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	83,319	88,344
Ecoservices | Industrial, mining & automotive
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	50,894	44,656
Advanced Materials & Catalysts
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	18,935	23,134
Advanced Materials & Catalysts | Clean fuels, emission control & other
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Advanced Materials & Catalysts | Polyethylene, polymers & engineered plastics
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	18,935	23,134
Advanced Materials & Catalysts | Regeneration and treatment services
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Advanced Materials & Catalysts | Industrial, mining & automotive
Disaggregated Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	$ 0	$ 0

Fair Value Measurements - (Deta

Fair Value Measurements - (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Derivative assets:
Interest rate caps	$ 22,066	$ 19,021
Derivative liabilities:
Derivative Liability	743	2,496
Quoted Prices in Active Markets (Level 1)
Derivative assets:
Interest rate caps	0	0
Derivative liabilities:
Derivative Liability	0	0
Significant Other Observable Inputs (Level 2)
Derivative assets:
Interest rate caps	22,066	19,021
Derivative liabilities:
Derivative Liability	743	2,496
Significant Unobservable Inputs (Level 3)
Derivative assets:
Interest rate caps	0	0
Derivative liabilities:
Derivative Liability	$ 0	$ 0

Stockholders' Equity - Pre-tax

Stockholders' Equity - Pre-tax and After-tax Components of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Other Comprehensive Income (Loss) [Line Items]
Pre-tax amount	$ 3,460	$ (8,150)
Tax benefit/ (expense)	(1,286)	2,391
Total other comprehensive income (loss)	2,174	(5,759)
Defined benefit and other postretirement plans
Other Comprehensive Income (Loss) [Line Items]
Pre-tax amount	(8)	(32)
Tax benefit/ (expense)	2	8
Total other comprehensive income (loss)	(6)	(24)
Net loss (gain)
Other Comprehensive Income (Loss) [Line Items]
Pre-tax amount	(1)	(1)
Tax benefit/ (expense)	0	0
Total other comprehensive income (loss)	(1)	(1)
Net prior service cost (credit)
Other Comprehensive Income (Loss) [Line Items]
Pre-tax amount	(7)	(31)
Tax benefit/ (expense)	2	8
Total other comprehensive income (loss)	(5)	(23)
Net gain (loss) from hedging activities
Other Comprehensive Income (Loss) [Line Items]
Pre-tax amount	5,152	(10,303)
Tax benefit/ (expense)	(1,288)	2,383
Total other comprehensive income (loss)	3,864	(7,920)
Foreign currency translation
Other Comprehensive Income (Loss) [Line Items]
Pre-tax amount	(1,684)	2,185
Tax benefit/ (expense)	0	0
Total other comprehensive income (loss)	$ (1,684)	$ 2,185

Stockholders' Equity - Change b

Stockholders' Equity - Change by Component (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 705,464	$ 707,229
Other comprehensive income (loss) before reclassifications	5,672	(5,257)
Amounts reclassified from accumulated other comprehensive income	(3,498)	(502)
Total other comprehensive income (loss)	2,174	(5,759)
Ending balance	711,356	674,151
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(958)	5,992
Total other comprehensive income (loss)	2,174	(5,759)
Ending balance	1,216	233
Defined benefit and other postretirement plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	612	(508)
Other comprehensive income (loss) before reclassifications	0	(48)
Amounts reclassified from accumulated other comprehensive income	(6)	24
Total other comprehensive income (loss)	(6)	(24)
Ending balance	606	(532)
Net gain (loss) from hedging activities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	12,546	24,672
Other comprehensive income (loss) before reclassifications	7,356	(7,394)
Amounts reclassified from accumulated other comprehensive income	(3,492)	(526)
Total other comprehensive income (loss)	3,864	(7,920)
Ending balance	16,410	16,752
Foreign currency translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(14,116)	(18,172)
Other comprehensive income (loss) before reclassifications	(1,684)	2,185
Amounts reclassified from accumulated other comprehensive income	0	0
Total other comprehensive income (loss)	(1,684)	2,185
Ending balance	$ (15,800)	$ (15,987)

Stockholders' Equity - Reclassi

Stockholders' Equity - Reclassifications out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income	$ (216)	$ 427
Total before tax	2,400	(524)
Interest expense, net	13,409	9,832
Tax expense	(1,179)	(947)
Amounts Reclassified from Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications for the period	3,498	502
Defined benefit and other postretirement plans  | Amounts Reclassified from Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	8	(32)
Tax expense	(2)	8
Total reclassifications for the period	6	(24)
Net loss (gain) | Amounts Reclassified from Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income	1	(1)
Net prior service cost (credit) | Amounts Reclassified from Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other (expense) income	7	(31)
Net gain (loss) from hedging activities | Amounts Reclassified from Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense, net	(4,656)	(698)
Tax expense	(1,164)	(172)
Total reclassifications for the period	$ 3,492	$ 526

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Apr. 27, 2022	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Equity, Class of Treasury Stock [Line Items]
Repurchases of common shares value		$ 218,599		$ 226,710
Shares withheld for tax withholding obligation (in shares)		128,801	95,269
Fair value of shares withheld for tax payments		$ 1,218	$ 866
April 2022 Stock Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount	$ 450,000
Stock repurchase program, period (in years)	4 years
Shares acquired (in shares)		0	3,000,000
Average cost per share (in dollars per share)			$ 9.95
Repurchases of common shares value			$ 29,850
Remaining authorized repurchase amount		$ 234,592

Goodwill - (Details)

Goodwill - (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 404,470
Foreign exchange impact	(218)
Ending balance	404,252
Ecoservices
Goodwill [Roll Forward]
Beginning balance	326,589
Foreign exchange impact	0
Ending balance	326,589
Advanced Materials & Catalysts
Goodwill [Roll Forward]
Beginning balance	77,881
Foreign exchange impact	(218)
Ending balance	$ 77,663

Other Operating Expense, Net -

Other Operating Expense, Net - (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Other Income and Expenses [Abstract]
Amortization expense	$ 2,645	$ 2,637
Transaction and other related costs	58	1,434
Restructuring, integration and business optimization costs	226	1,023
Net loss on asset disposals	648	1,178
Other, net	89	444
Total other operating expense, net	$ 3,666	$ 6,716

Inventories, Net - Classificati

Inventories, Net - Classification (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Finished products and work in process	$ 48,001	$ 41,658
Raw materials	4,502	3,457
Inventories, net	52,503	45,115
Valued at lower of cost or market:
LIFO basis	30,642	24,815
Valued at lower of cost and net realizable value:
FIFO or average cost basis	$ 21,861	$ 20,300

Investments in Affiliated Com_3

Investments in Affiliated Companies - Ownership Percentage (Details)	Mar. 31, 2024
Zeolyst International
Schedule of Equity Method Investments [Line Items]
Percent ownership	50%
Zeolyst C.V.
Schedule of Equity Method Investments [Line Items]
Percent ownership	50%

Investments in Affiliated Com_4

Investments in Affiliated Companies - Summarized Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Schedule of Equity Method Investments [Line Items]
Gross profit	$ 39,223	$ 36,493
Operating income	13,953	8,658
Net income (loss)	1,221	(1,471)
Equity Method Investment, Nonconsolidated Investee
Schedule of Equity Method Investments [Line Items]
Sales	56,860	55,897
Gross profit	17,177	10,110
Operating income	6,844	2,399
Net income (loss)	$ 7,345	$ 3,647

Investments in Affiliated Com_5

Investments in Affiliated Companies - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Business Combination
Amortization of investment in affiliate step-up	$ (1,601,000)	$ (1,601,000)
Accounts payable	33,544,000		$ 40,195,000
Related Party
Business Combination
Accounts receivable, after allowance for credit loss	3,136,000		3,231,000
Accounts payable	0		1,351,000
Sales	0	1,700,000
Purchases from related party	0	$ 0
Business Combination
Business Combination
Net purchase accounting fair value adjustments	223,014,000		$ 224,614,000
Amortization of investment in affiliate step-up	$ 1,601,000

Property, Plant and Equipment -

Property, Plant and Equipment - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment
Property, plant and equipment, gross	$ 1,056,871	$ 1,044,202
Less: accumulated depreciation	(484,564)	(467,298)
Property, plant and equipment, net	572,307	576,904
Land
Property, Plant and Equipment
Property, plant and equipment, gross	96,804	96,833
Buildings and improvements
Property, Plant and Equipment
Property, plant and equipment, gross	85,761	84,860
Machinery and equipment
Property, Plant and Equipment
Property, plant and equipment, gross	825,370	820,509
Construction in progress
Property, Plant and Equipment
Property, plant and equipment, gross	$ 48,936	$ 42,000

Property, Plant and Equipment_2

Property, Plant and Equipment - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Property, Plant and Equipment [Abstract]
Depreciation	$ 18,415	$ 16,692

Long-term Debt - Summary of Lon

Long-term Debt - Summary of Long-Term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument
Total debt	$ 875,250	$ 877,500
Original issue discount	(5,831)	(6,162)
Deferred financing costs	(3,199)	(3,392)
Total debt, net of original issue discount and deferred financing costs	866,220	867,946
Less: current portion	(9,000)	(9,000)
Total long-term debt, excluding current portion	857,220	858,946
2021 Term Loan Facility
Debt Instrument
Total debt	875,250	877,500
ABL Facility
Debt Instrument
Total debt	$ 0	$ 0

Long-term Debt - Narrative (Det

Long-term Debt - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
2021 Term Loan Facility
Debt Instrument
Long-term debt, fair value	$ 873,062	$ 876,403
2021 Term Loan Facility | Secured Overnight Financing Rate
Debt Instrument
Effective interest rate	7.91%
Variable rate floor	0.0050
Credit spread adjustment	0.10%
Variable rate on spread	2.75%
First lien leverage ratio	0.0250
ABL Facility | Secured Overnight Financing Rate
Debt Instrument
Effective interest rate	8.75%
Credit spread adjustment	0.10%
ABL Facility | Secured Overnight Financing Rate | Minimum
Debt Instrument
Variable rate on spread	1.25%
ABL Facility | Secured Overnight Financing Rate | Maximum
Debt Instrument
Variable rate on spread	1.75%
ABL Facility | Base Rate | Minimum
Debt Instrument
Variable rate on spread	0.25%
ABL Facility | Base Rate | Maximum
Debt Instrument
Variable rate on spread	0.75%

Financial Instruments - Interes

Financial Instruments - Interest Rate Cap Agreements (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) derivative_instrument_held derivative
Derivative
Number of instruments | derivative	4
Annuitized premium of instruments in effect	$ 24,817
Cash flow hedging
Derivative
Number of instruments in effect | derivative_instrument_held	3
Current notional amount of instruments in effect	$ 650,000

Financial Instruments - Narrati

Financial Instruments - Narrative (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($) derivative_instrument_held
Derivative
Amount of derivative loss expected to be transferred from OCI	$ 9,199
Cash flow hedging
Derivative
Number of instruments in effect | derivative_instrument_held	3
Notional amount	$ 650,000
Derivative, cap interest rate	1%
Cash flow hedging | Interest Rate Cap One
Derivative
Notional amount	$ 250,000
Cash flow hedging | Interest Rate Cap Two
Derivative
Notional amount	250,000
Cash flow hedging | Interest Rate Cap Three
Derivative
Notional amount	150,000
Cash flow hedging | Interest Rate Cap Three Period Two
Derivative
Notional amount	$ 175,000

Financial Instruments - Fair Va

Financial Instruments - Fair Values of Derivative Instruments Held (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Derivative assets
Derivative Asset, Current, Statement of Financial Position [Extensible Enumeration]	Prepaid and other current assets	Prepaid and other current assets
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other long-term assets	Other long-term assets
Derivative asset, current	$ 13,490	$ 13,419
Derivative liabilities
Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other long-term liabilities	Other long-term liabilities
Derivatives designated as hedging instrument | Cash flow hedging | Interest rate caps
Derivative assets
Derivative asset, current	$ 13,490	$ 13,419
Derivative asset, noncurrent	8,576	5,602
Interest rate caps	22,066	19,021
Derivative liabilities
Derivative liability, noncurrent	743	2,496
Derivative liability	$ 743	$ 2,496

Financial Instruments - Effect

Financial Instruments - Effect of Derivative Instruments Designated as Hedges on Other Comprehensive Income (Details) - Interest rate caps - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Amount of gain (loss) reclassified from AOCI into income
Amount of gain (loss) recognized in OCI on derivatives	$ 9,808	$ (9,605)
Interest (expense) income
Amount of gain (loss) reclassified from AOCI into income
Amount of gain (loss) reclassified from AOCI into income	$ (4,656)	$ 698

Financial Instruments - Cash Fl

Financial Instruments - Cash Flow Hedge Impact on Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Derivative
Interest expense, net	$ (13,409)	$ (9,832)

Income Taxes - (Details)

Income Taxes - (Details)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income Tax Disclosure [Abstract]
Effective income tax rate	49.10%	(180.70%)

Benefit Plans - (Details)

Benefit Plans - (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Defined Benefit Pension Plans
Defined Benefit Plan, Net Periodic Expense (Benefit)
Interest cost	$ 808	$ 871
Expected return on plan assets	(827)	(837)
Net periodic (benefit) expense	(19)	34
Other Postretirement Benefits Plan
Defined Benefit Plan, Net Periodic Expense (Benefit)
Interest cost	6	6
Amortization of prior service credit	(7)	(31)
Amortization of net gain	(1)	(1)
Net periodic (benefit) expense	$ (2)	$ (26)

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Related Party Transaction [Line Items]
Accounts payable, related parties	$ 33,544,000		$ 40,195,000
Related Party
Related Party Transaction [Line Items]
Sales	0	$ 1,700,000
Purchases from related party	0	0
Accounts receivable, after allowance for credit loss	3,136,000		3,231,000
Accounts payable, related parties	0		1,351,000
Related Party | Corporate Joint Venture
Related Party Transaction [Line Items]
Accounts receivable, after allowance for credit loss	3,115,000		3,164,000
Accounts payable, related parties	0		$ 0
Related Party | INEOS Capital Partners
Related Party Transaction [Line Items]
Sales	1,249,000	595,000
Related Party | Operating Lease Rental Payments | Corporate Joint Venture
Related Party Transaction [Line Items]
Sales	77,000	77,000
Related Party | Sales from Partnership to Company
Related Party Transaction [Line Items]
Purchases from related party	0	0
Related Party | Manufacturing Costs | Corporate Joint Venture
Related Party Transaction [Line Items]
Sales	4,034,000	5,841,000
Related Party | Services | Corporate Joint Venture
Related Party Transaction [Line Items]
Sales	4,300,000	3,634,000
Related Party | Product Demonstration Costs | Corporate Joint Venture
Related Party Transaction [Line Items]
Sales	$ 357,000	$ 500,000

Reportable Segments - Summary F

Reportable Segments - Summary Financial Information by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting
Sales	$ 160,537	$ 160,874
Adjusted EBITDA from reportable segments	52,623	49,776
Equity in net income from affiliated companies	2,072	223
Amortization of investment in affiliate step-up	1,601	1,601
Joint venture depreciation, amortization and interest	3,254	3,609
Ecoservices
Segment Reporting
Sales	141,602	137,740
Adjusted EBITDA from reportable segments	41,494	36,787
Advanced Materials & Catalysts
Segment Reporting
Sales	18,935	23,134
Adjusted EBITDA from reportable segments	11,129	12,989
Advanced Materials & Catalysts | Zeolyst Joint Venture
Segment Reporting
Sales	23,481	22,074
Adjusted EBITDA from reportable segments	$ 6,927	5,436
Percent ownership	50%
Equity in net income from affiliated companies	$ 2,072	226
Amortization of investment in affiliate step-up	1,601	1,601
Joint venture depreciation, amortization and interest	$ 3,254	$ 3,609

Reportable Segments - Reconcili

Reportable Segments - Reconciliation of Net Income to Segment Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting [Abstract]
Income (loss) before income taxes	$ 2,400	$ (524)
Interest expense, net	13,409	9,832
Depreciation and amortization	21,933	20,197
Unallocated corporate expenses	7,081	6,926
Joint venture depreciation, amortization and interest	3,254	3,609
Amortization of investment in affiliate step-up	1,601	1,601
Net loss on asset disposals	648	1,178
Foreign exchange loss (gain)	178	(738)
LIFO (benefit) expense	(1,124)	1,399
Transaction and other related costs	58	1,434
Equity-based compensation	3,680	4,068
Restructuring, integration and business optimization expenses	226	1,023
Other Nonoperating Income (Expense)	(721)	(229)
Adjusted EBITDA from reportable segments	$ 52,623	$ 49,776

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details)	Mar. 31, 2024 shares
Share-Based Payment Arrangement [Abstract]
Number of shares available for grant (in shares)	7,994,600

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Units and Performance Stock Units (Details)	1 Months Ended	3 Months Ended
	Feb. 29, 2024	Mar. 31, 2024 $ / shares shares
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Granted (in shares) | shares		1,108,063
Granted, weighted average grant date fair value (in dollars per share) | $ / shares		$ 8.82
Restricted Stock Units | Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award
Award requisite service period (in years)		1 year
Restricted Stock Units | Employee
Share-based Compensation Arrangement by Share-based Payment Award
Award requisite service period (in years)		3 years
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Granted (in shares) | shares		535,629
Granted, weighted average grant date fair value (in dollars per share) | $ / shares		$ 10.23
Performance Stock Units | 2024 Grants
Share-based Compensation Arrangement by Share-based Payment Award
Granted (in shares) | shares		535,629
Award requisite performance period		3 years
Granted, weighted average grant date fair value (in dollars per share) | $ / shares		$ 11.64
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected dividend yield		0%
Risk-free interest rate		4.09%
Expected volatility		39.45%
Expected term (in years)		2 years 11 months 12 days
Performance Stock Units | 2024 Grants | Company Performance Measure
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Granted, percentage of target		0.50
Performance Stock Units | 2024 Grants | Total Shareholder Return (TSR)
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Granted, percentage of target		0.50
Performance Stock Units | 2024 Grants | Minimum
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting percentage		50%
Performance Stock Units | 2024 Grants | Maximum
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting percentage		200%
Performance Stock Units | 2021 Grants
Share-based Compensation Arrangement by Share-based Payment Award
Award requisite service period (in years)	3 years

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of RSU and PSU Activity (Details)	3 Months Ended
	Mar. 31, 2024 $ / shares shares
Restricted Stock Units
Number of units
Nonvested, beginning balance (in shares) | shares	1,962,828
Granted (in shares) | shares	1,108,063
Vested (in shares) | shares	(996,148)
Forfeited (in shares) | shares	(19,197)
Nonvested, ending balance (in shares) | shares	2,055,546
Weighted average grant date fair value (per share)
Nonvested, beginning balance (in dollars per share) | $ / shares	$ 10.55
Granted (in dollars per share) | $ / shares	8.82
Vested (in dollars per share) | $ / shares	10.36
Forfeited (in dollars per share) | $ / shares	11.10
Nonvested, ending balance (in dollars per share) | $ / shares	$ 9.35
Performance Stock Units
Number of units
Nonvested, beginning balance (in shares) | shares	959,217
Granted (in shares) | shares	535,629
Vested (in shares) | shares	0
Forfeited (in shares) | shares	(126,497)
Nonvested, ending balance (in shares) | shares	1,368,349
Weighted average grant date fair value (per share)
Nonvested, beginning balance (in dollars per share) | $ / shares	$ 11.84
Granted (in dollars per share) | $ / shares	10.23
Vested (in dollars per share) | $ / shares	0
Forfeited (in dollars per share) | $ / shares	12.99
Nonvested, ending balance (in dollars per share) | $ / shares	$ 11.10
RSA
Number of units
Granted (in shares) | shares	4,540
Weighted average grant date fair value (per share)
Granted (in dollars per share) | $ / shares	$ 8.81

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award
Stock compensation expense	$ 3,680	$ 4,068
Stock-based compensation expense, tax benefit	$ 902	$ 973
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Forfeited, performance-based restricted shares (in shares)	19,197
Unrecognized stock-based compensation expense	$ 16,857
Unrecognized stock-based compensation expense, period for recognition	2 years 3 days
Performance Stock Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award
Unrecognized stock-based compensation expense	$ 10,670
Unrecognized stock-based compensation expense, period for recognition	2 years 4 months 9 days

Earnings per Share - Reconcilia

Earnings per Share - Reconciliation from Basic to Diluted Weighted Average Shares Outstanding (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Weighted average shares outstanding – Basic (in shares)	116,955,043	122,178,867
Dilutive effect of unvested common shares and restricted stock units with service conditions, performance stock units considered probable of vesting and assumed stock option exercises and conversions (in shares)	496,106	0
Weighted average shares outstanding – Diluted (in shares)	117,451,149	122,178,867

Earnings per Share - Calculatio

Earnings per Share - Calculation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Numerator:
Net income (loss)	$ 1,221	$ (1,471)
Denominator:
Weighted average shares outstanding – Basic (in shares)	116,955,043	122,178,867
Weighted average shares outstanding – Diluted (in shares)	117,451,149	122,178,867
Net income (loss) per share:
Basic income per share (in dollars per share)	$ 0.01	$ (0.01)
Diluted income per share (in dollars per share)	$ 0.01	$ (0.01)

Earnings per Share - Anti-dilut

Earnings per Share - Anti-dilutive Shares (Details) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
RSA
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive stock options (in shares)	0	200,096
Stock options with performance only targets not achieved
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive stock options (in shares)	0	208,968
Anti-dilutive RSUs and PSUs(1)
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive stock options (in shares)	558,989	432,308
Anti-dilutive stock options, exclusions (in shares)		1,044,098
Anti-dilutive stock options(1)
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive stock options (in shares)	367,100	695,777
Anti-dilutive stock options, exclusions (in shares)		352,771

Supplemental Cash Flow Inform_3

Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash paid during the period for:
Income taxes, net of refunds	$ 3,608	$ 136
Interest	12,569	15,185
Non-cash investing activity:
Capital expenditures acquired on account but unpaid as of the period end	713	650
Right-of-use assets obtained in exchange for new lease liabilities (non-cash):
Operating leases	$ 2,131	$ 1,621