Stepan (SCL) 10-K 29 Feb 24 2023 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2023	Jan. 31, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2023
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Trading Symbol	SCL
Entity Registrant Name	STEPAN COMPANY
Entity Well Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Central Index Key	0000094049
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Tax Identification Number	36-1823834
Entity File Number	1-4462
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	1101 Skokie Boulevard
Entity Address, Address Line Two	Suite 500
Entity Address, City or Town	Northbrook
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60062
City Area Code	847
Local Phone Number	446-7500
Security Exchange Name	NYSE
Title of 12(b) Security	Common Stock, $1 par value
Document Annual Report	true
Document Transition Report	false
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding		22,381,409
Entity Public Float			$ 1,992,777,852
ICFR Auditor Attestation Flag	true
Auditor Name	DELOITTE & TOUCHE LLP
Auditor Location	Chicago, Illinois
Auditor Firm ID	34
Documents Incorporated by Reference	Documents Incorporated by Reference Part of Form 10-K Document Incorporated Part III, Items 10-14 Portions of the Proxy Statement for Annual Meeting of Stockholders expected to be held April 30, 2024. * Based on reported ownership by all directors and executive officers at June 30, 2023 .
Document Financial Statement Error Correction [Flag]	false

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Net Sales (Note 1)	[1]	$ 2,325,768,000	$ 2,773,270,000	$ 2,345,966,000
Cost of Sales		2,048,170,000	2,346,201,000	1,950,156,000
Gross Profit		277,598,000	427,069,000	395,810,000
Operating Expenses:
Selling (Note 1)		48,367,000	59,030,000	59,186,000
Administrative (Note 1)		93,202,000	102,177,000	92,906,000
Research, development and technical services (Note 1)		59,039,000	66,633,000	62,689,000
Deferred compensation (income) expense (Note 12)		4,371,000	(9,393,000)	6,895,000
Total Operating expenses		204,979,000	218,447,000	221,676,000
Goodwill and other intangibles impairment (Note 4)		2,038,000	978,000
Business restructuring, assets impairment and loss on asset disposition (Note 22)	[2]	11,968,000	308,000	3,353,000
Operating Income		58,613,000	207,336,000	170,781,000
Other Income (Expense):
Interest, net (Note 6)		(12,103,000)	(9,809,000)	(5,753,000)
Other, net (Note 8)		1,881,000	(8,824,000)	7,509,000
Nonoperating Income (Expense), Total		(10,222,000)	(18,633,000)	1,756,000
Income Before Provision for Income Taxes		48,391,000	188,703,000	172,537,000
Provision for Income Taxes (Note 9)		8,187,000	41,550,000	34,642,000
Net Income		40,204,000	147,153,000	137,895,000
Net Income Attributable to Noncontrolling Interest (Note 1)				(91,000)
Net Income Attributable to Stepan Company		$ 40,204,000	$ 147,153,000	$ 137,804,000
Net Income Per Common Share Attributable to Stepan Company (Note 18):
Basic		$ 1.77	$ 6.46	$ 6.01
Diluted		$ 1.75	$ 6.38	$ 5.92
Shares Used to Compute Net Income Per Common Share Attributable to Stepan Company (Note 18):
Basic		22,777	22,781	22,922
Diluted		22,946	23,064	23,287
[1] Includes net property, plant and equipment, goodwill and other intangible assets. See Note 22, Business Restructuring, Assets Impairment and Asset Disposition , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) regarding business restructuring and asset disposition costs.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net Income	$ 40,204	$ 147,153	$ 137,895
Other Comprehensive Income:
Foreign currency translation adjustments (Note 19)	40,423	(21,567)	(28,154)
Defined benefit pension plans:
Net actuarial gain (loss) arising in period (net of tax benefit of $508, tax benefit of $894 and tax expense of $2,661 for 2023, 2022 and 2021, respectively)	(1,630)	(2,857)	8,188
Amortization of prior service cost included in pension expense (net of tax expense of $2, $3 and $4 for 2023, 2022 and 2021, respectively)	8	6	8
Amortization of actuarial loss included in pension expense (net of tax expense of $99, $599 and $1,157 for 2023, 2022 and 2021, respectively)	293	1,794	3,643
Net defined benefit pension plan activity (Note 19)	(1,329)	(1,057)	11,839
Cash flow hedges:
Cash flow hedge activity	(2,174)	8,357
Reclassifications to income in period	(10)	(9)	(9)
Net cash flow hedge activity (Note 19)	(2,184)	8,348	(9)
Other Comprehensive Income	36,910	(14,276)	(16,324)
Comprehensive Income	77,114	132,877	121,571
Comprehensive Income Attributable to Noncontrolling Interest			(122)
Comprehensive Income Attributable to Stepan Company	$ 77,114	$ 132,877	$ 121,449

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net actuarial gain (loss) arising in period, tax expense (benefit)	$ (508)	$ (894)	$ 2,661
Amortization of prior service cost included in pension expense, tax	2	3	4
Amortization of actuarial loss included in pension expense, tax	$ 99	$ 599	$ 1,157

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 129,823,000	$ 173,750,000
Receivables, less allowances of $11,143 in 2023 and $11,100 in 2022	422,050,000	436,914,000
Inventories (Note 5)	265,558,000	402,531,000
Other current assets	34,452,000	31,607,000
Total current assets	851,883,000	1,044,802,000
Property, Plant and Equipment:
Land	52,842,000	50,695,000
Buildings and improvements	335,033,000	293,264,000
Machinery and equipment	1,796,820,000	1,640,478,000
Construction in progress	400,363,000	386,115,000
Property, Plant and Equipment, Gross	2,585,058,000	2,370,552,000
Less: Accumulated depreciation	(1,378,393,000)	(1,297,255,000)
Property, plant and equipment, net	1,206,665,000	1,073,297,000
Goodwill, net (Note 4)	97,442,000	95,922,000
Other intangible assets, net (Note 4)	52,571,000	58,026,000
Long-term investments (Note 2)	26,804,000	23,294,000
Operating lease assets (Note 7)	70,646,000	62,540,000
Other non-current assets	57,343,000	75,291,000
Total Assets	2,363,354,000	2,433,172,000
Current Liabilities:
Current maturities of debt (Note 6)	252,898,000	132,111,000
Accounts payable	233,031,000	375,726,000
Accrued liabilities (Note 14)	121,941,000	162,812,000
Total current liabilities	607,870,000	670,649,000
Deferred income taxes (Note 9)	10,373,000	10,179,000
Long-term debt, less current maturities (Note 6)	401,248,000	455,029,000
Non-current operating lease liability (Note 7)	58,026,000	50,559,000
Other non-current liabilities (Note 15)	69,347,000	80,691,000
Commitments and Contingencies (Note 16)
Equity (Note 10):
Common stock, $1 par value; 60,000,000 authorized shares; 27,005,852 issued shares in 2023 and 26,840,843 issued shares in 2022	27,006,000	26,841,000
Additional paid-in capital	247,032,000	237,202,000
Accumulated other comprehensive loss (Note 19)	(130,602,000)	(167,512,000)
Retained earnings	1,257,466,000	1,250,130,000
Less: Common treasury stock, at cost, 4,628,072 shares in 2023 and 4,605,858 shares in 2022	(184,412,000)	(180,596,000)
Total Stepan Company stockholders’ equity	1,216,490,000	1,166,065,000
Total Liabilities and Equity	$ 2,363,354,000	$ 2,433,172,000

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Allowances	$ 11,143	$ 11,100
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	27,005,852	26,840,843
Treasury stock, shares	4,628,072	4,605,858

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash Flows From Operating Activities
Net income	$ 40,204,000	$ 147,153,000	$ 137,895,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	105,338,000	94,650,000	90,876,000
Deferred compensation	4,371,000	(9,393,000)	6,895,000
Realized and unrealized (gains) losses on long-term investments	(4,314,000)	8,188,000	(2,289,000)
Stock-based compensation	5,741,000	13,851,000	11,716,000
Deferred income taxes	18,303,000	(27,452,000)	(33,605,000)
Goodwill and other intangibles impairment (Note 4)	2,038,000	978,000
Other non-cash items	5,123,000	1,752,000	2,158,000
Changes in assets and liabilities, excluding effects of acquisitions:
Receivables, net	32,007,000	(26,153,000)	(104,231,000)
Inventories	144,846,000	(99,394,000)	(79,258,000)
Other current assets	(4,528,000)	(4,354,000)	(1,434,000)
Accounts payable and accrued liabilities	(158,924,000)	54,173,000	44,414,000
Pension liabilities	(1,204,000)	(1,821,000)	(1,729,000)
Environmental and legal liabilities	(11,985,000)	9,547,000	450,000
Deferred revenues	(2,140,000)	(962,000)	277,000
Net Cash Provided By Operating Activities	174,876,000	160,763,000	72,135,000
Cash Flows From Investing Activities
Expenditures for property, plant and equipment	(260,335,000)	(301,553,000)	(194,482,000)
Proceeds from asset disposition			4,149,000
Asset acquisition (Note 20)			(3,503,000)
Business acquisitions, net of cash acquired (Note 20)		(9,693,000)	(184,473,000)
Other, net	1,669,000	3,156,000	1,480,000
Net Cash Used In Investing Activities	(258,666,000)	(308,090,000)	(376,829,000)
Cash Flows From Financing Activities
Revolving debt and bank overdrafts, net (Note 6)	104,717,000	186,551,000	2,861,000
Other debt borrowings (Note 6)		75,000,000	200,000,000
Other debt repayments (Note 6)	(37,858,000)	(37,857,000)	(37,858,000)
Dividends paid	(32,868,000)	(30,573,000)	(28,083,000)
Company stock repurchased		(24,949,000)	(16,969,000)
Stock option exercises	2,795,000	782,000	1,369,000
Other, net	(3,502,000)	(2,745,000)	(3,987,000)
Net Cash Provided By Financing Activities	33,284,000	166,209,000	117,333,000
Effect of Exchange Rate Changes on Cash	6,579,000	(4,318,000)	(3,391,000)
Net Increase (Decrease) in Cash and Cash Equivalents	(43,927,000)	14,564,000	(190,752,000)
Cash and Cash Equivalents at Beginning of Year	173,750,000	159,186,000	349,938,000
Cash and Cash Equivalents at End of Year	129,823,000	173,750,000	159,186,000
Supplemental Cash Flow Information
Cash payments of income taxes, net of refunds/payments	29,558,000	41,617,000	92,867,000
Cash payments of interest	$ 27,951,000	$ 16,526,000	$ 9,542,000

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands		Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Common Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Noncontrolling Interests [Member]
Beginning Balance at Dec. 31, 2020		$ 988,365	$ 26,658	$ 206,716	$ (133,629)	$ (136,881)	$ 1,023,829	$ 1,672
Issuance of common stock under stock option plan		1,369	20	1,349
Purchase of common stock		(16,969)			(16,969)
Stock-based and deferred compensation		9,734	83	12,755	(3,104)
Net income		137,895					137,804	91
Other comprehensive income		(16,324)				(16,355)		31
Cash dividends paid:
Common stock		(28,083)					(28,083)
Other	[1]	(1,794)						$ (1,794)
Ending Balance at Dec. 31, 2021		1,074,193	26,761	220,820	(153,702)	(153,236)	1,133,550
Issuance of common stock under stock option plan		782	12	770
Purchase of common stock		(24,949)			(24,949)
Stock-based and deferred compensation		13,735	68	15,612	(1,945)
Net income		147,153					147,153
Other comprehensive income		(14,276)				(14,276)
Cash dividends paid:
Common stock		(30,573)					(30,573)
Ending Balance at Dec. 31, 2022		1,166,065	26,841	237,202	(180,596)	(167,512)	1,250,130
Issuance of common stock under stock option plan		2,875	53	2,822
Stock-based and deferred compensation		3,304	112	7,008	(3,816)
Net income		40,204					40,204
Other comprehensive income		36,910				36,910
Cash dividends paid:
Common stock		(32,868)					(32,868)
Ending Balance at Dec. 31, 2023		$ 1,216,490	$ 27,006	$ 247,032	$ (184,412)	$ (130,602)	$ 1,257,466
[1] Reflects the derecognition of noncontrolling interest due to the dissolution of the China joint venture. See Note 1, Summary of Significant Accounting Policies , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K).

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Number of shares of common stock issued under stock option plan	52,999	11,888	20,435
Number of common stock shares purchased		251,120	135,103
Common stock	$ 1.470	$ 1.370	$ 1.250
Common Stock [Member]
Number of shares of common stock issued under stock option plan	52,999	11,888	20,435
Additional Paid-in Capital [Member]
Number of shares of common stock issued under stock option plan	52,999	11,888	20,435
Common Treasury Stock [Member]
Number of common stock shares purchased		251,120	135,103

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ 40,204	$ 147,153	$ 137,804

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	1. Summary of Significant Accounting Policies Nature of Operations Stepan Company’s (the Company) operations consist predominantly of the production and sale of specialty and intermediate chemicals, which are sold to other manufacturers for use in a variety of end products. Principal markets for all products are manufacturers of cleaning and washing compounds (including detergents, shampoos, fabric softeners, toothpastes and household cleaners), paints, cosmetics, food, beverages, nutritional supplements, agricultural products, plastics, furniture, automotive equipment, insulation and refrigeration. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires Company management to make estimates and assumptions that affect the reported amounts of assets, liabilities, income and expenses at the date of the financial statements and to provide disclosures of contingent assets, liabilities and related amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Principles of Consolidation The consolidated financial statements include the accounts of the Company and all wholly-owned subsidiaries in which the Company exercises controlling influence. The equity method is used to account for investments in which the Company exercises significant but noncontrolling influence. Intercompany balances and transactions are eliminated in consolidation. Prior to the fourth quarter of 2021, the Company had an 80 percent ownership interest in the Nanjing Stepan Jinling Chemical Limited Liability Company (a joint venture) and exercised controlling influence over the entity. As a result, the China joint venture results were included in the Company’s consolidated financial statements. The partner’s interest in the joint venture’s net income was reported in the net income attributable to noncontrolling interest line of the consolidated statements of income and its interest in the net assets of the joint venture was reported in the noncontrolling interest line (a component of equity separate from Company equity) of the consolidated balance sheets. The joint venture was dissolved during the fourth quarter of 2021. Business Combinations The Company makes acquisitions from time to time. When such acquisitions occur, the Company applies the accounting guidance per FASB ASC Topic 805, Business Combinations (ASC 805), to determine whether the acquisition should be treated as an asset acquisition or a business combination. When the acquisition meets the criteria of a business combination the Company recognizes the identifiable assets acquired and liabilities assumed at their estimated fair values as of the date of the acquisition. The Company recognizes goodwill for any portion of the purchase price that exceeds the sum of the net fair value of all the assets purchased in the acquisition and the liabilities assumed. Considerable estimates, complex judgments and assumptions are typically required to arrive at the fair value of elements acquired in a business combination, inclusive of discount rates, customer attrition rates, royalty rates, economic lives, and estimated future cash flows expected to be generated from the assets acquired. These items are typically most relevant to the fair valuation of identifiable intangible assets and property, plant and equipment. In some instances, the purchase price allocation of an acquisition is not complete by the end of a reporting period. This situation most typically arises when an acquisition is complex and/or completed very close to the end of a reporting period and all necessary information is not available by the end of the reporting period in which the acquisition occurs. In these instances, the Company reports provisional amounts for any incomplete items and makes subsequent adjustments as necessary information becomes available or determines that additional information is not obtainable. Any subsequent adjustments could have a material impact on the Company’s financial position or results of operations as they could impact the initial fair values assigned to intangible assets and property, plant and equipment and/or their estimated economic lives. ASC 805 requires purchase price allocations to be finalized within one year from the acquisition date. Cash and Cash Equivalents The Company considers all highly liquid investments with purchased maturities of three months or less to be cash equivalents. At December 31, 2023 , the Company’s cash and cash equivalents totaled $ 129,823,000 including $ 15,117,000 in money market funds each rated AAAm by Standard and Poor’s, Aaa-mf by Moody’s and AAAmmf by Fitch. Cash in U.S. demand deposit accounts totaled $ 6,374,000 , and cash of the Company’s non-U.S. subsidiaries held outside the U.S. totaled $ 108,332,000 as of December 31, 2023. At December 31, 2022 , the Company’s cash and cash equivalents totaled $ 173,750,000 including $ 64,851,000 in money market funds, each of which was rated AAAm by Standard and Poor’s, Aaa-mf by Moody’s and AAAmmf by Fitch. Cash in U.S. demand deposit accounts totaled $ 11,811,000 and cash of the Company’s non-U.S. subsidiaries held outside the U.S. totaled $ 97,088,000 as of December 31, 2022 . Receivables and Credit Risk/Losses Receivables are stated net of allowances for doubtful accounts and other allowances and primarily include trade receivables from customers, as well as nontrade receivables from suppliers, governmental tax agencies and others. The Company is exposed to both credit risk and losses on accounts receivable balances. The Company’s credit risk and loss exposure predominately relates to the sale of products to its customers. When extending credit to customers the Company evaluates a customer’s credit worthiness based on a combination of qualitative and quantitative factors, inclusive of, but not limited to, a customer’s credit rating from external providers, financial condition and past payment experience. The Company performs credit reviews on all customers at inception and on a scheduled basis thereafter dependent on customer risk and the level of credit extended. Payment terms extended are short term in duration, typically ranging from 30 to 60 days . The majority of the Company’s sales are made to large companies that are able to weather periodic changes in economic conditions. This risk of losses is further mitigated by the Company’s diverse customer base, which is dispersed over various geographic regions and industrial sectors. No single customer comprised more than 10 percent of the Company’s consolidated net sales in 2023, 2022 or 2021. The Company maintains allowances for potential credit losses. With the adoption of ASU No. 2016-13, Financial Instruments – Credit Losses, the Company assesses the likelihood of default based on various factors, including the length of time receivables are past due, historical experience, current economic conditions and forward-looking economic forecasts. The Company also evaluates expected losses based on portfolios of data inclusive of geographical areas, specific end market uses of its products, etc. Although the Company’s historical credit loss experience has not been significant, its exposure to credit losses may increase if customers are adversely affected by economic challenges and/or uncertainty due to domestic or global recessions, disruptions due to pandemics, or other adverse global/regional events and customer specific factors. Specific customer allowances are recorded when a review of customer creditworthiness and current economic conditions indicate that collection is doubtful. General allowances are also maintained based on historical averages and trade receivable levels and incorporate existing economic conditions and forecast assumptions, when warranted. The Company reviews its reserves for credit losses on a quarterly basis. The Company also maintains other customer allowances that occur in the normal course of business. The following is an analysis of the allowance for doubtful accounts and other accounts receivable allowances for the years ended December 31, 2023, 2022 and 2021: (In thousands) 2023 2022 2021 Balance at January 1 $ 11,100 $ 10,157 $ 10,133 Provision charged to income 765 1,374 943 Accounts written off, net of recoveries ( 722 ) ( 431 ) ( 919 ) Balance at December 31 $ 11,143 $ 11,100 $ 10,157 Inventories Inventories are valued at cost, which is not in excess of net realizable value, and include material, labor and plant overhead costs. The first in, first out (FIFO) method is used to determine the cost of the Company’s inventory. Property, Plant and Equipment Depreciation of property, plant and equipment is provided on a straight-line basis over the estimated useful lives of the assets. Lives used for calculating depreciation are generally 30 years for buildings and 15 years for building improvements. For assets classified as machinery and equipment, lives generally used for calculating depreciation expense range from 10 to 15 years for manufacturing equipment, five to 10 years for furniture and fixtures, three to five years for vehicles and three to 10 years for computer equipment and software. The manufacturing of chemicals is capital intensive and a large majority of the assets included within machinery and equipment represent manufacturing equipment. Major renewals and betterments are capitalized in the property accounts, while maintenance and repairs ($ 80,226,000 , $ 82,110,000 , and $ 75,351,000 in 2023, 2022 and 2021, respectively), which do not renew or extend the life of the respective assets, are charged to operations as incurred. Land is not depreciated. The cost of property retired or sold, and the related accumulated depreciation, are removed from the accounts and any resulting gain or loss is reflected in income. Long-lived assets are reviewed for impairment when conditions exist that indicate the carrying amount of the assets may not be fully recoverable. Such conditions could include significant adverse changes in the business environment, significant declines in forecasted operations or an approved plan to discontinue an asset or an asset group before the end of its useful life. Included in the computer equipment and software component of machinery and equipment are costs related to the acquisition and development of internal-use software. Capitalized costs for internal-use software include external direct costs of materials and services consumed in obtaining and developing the software. For development projects where major internal resources are committed, payroll and payroll-related costs incurred during the application development phase of the project are also capitalized. The capitalized costs are amortized over the useful lives of the software, which are generally three to 10 years . Costs incurred in the preliminary project phase are expensed. Deferred implementation costs for hosted cloud computing service arrangements are stated at historical cost and amortized on a straight-line basis over the term of the hosting arrangement. Interest charges on borrowings applicable to major construction projects are capitalized. Deferred Compensation The Company sponsors deferred compensation plans that allow management employees to defer receipt of their annual cash incentive compensation and performance shares and non-employee directors to defer receipt of their fees and stock awards until retirement, departure from the Company or as elected by the participant. The plans allow for the deferred compensation to grow or decline based on the results of investment options chosen by the participants. The investment options include Company common stock and a limited selection of mutual funds. The Company funds the obligations associated with these plans by purchasing investment assets that match the investment choices made by the plan participants. A sufficient number of shares of treasury stock are maintained on hand to cover the equivalent number of shares that result from participants electing the Company common stock investment option. As a result, the Company must periodically purchase its common shares in the open market or in private transactions. Upon retirement or departure from the Company or at the elected time, participants receive cash amounts equivalent to the payment date value of the investment choices they have made or shares of Company common stock equal to the number of share equivalents held in the accounts. Some plan distributions may be made in cash or Company common stock at the option of the participant. Other plan distributions can only be made in Company common stock. For deferred compensation obligations that may be settled in cash, the Company must record appreciation in the market value of the investment choices made by participants as additional compensation expense. Conversely, declines in the value of Company stock or the mutual funds result in a reduction of compensation expense since such declines reduce the cash obligation of the Company as of the date of the financial statements. These market price movements may result in significant period-to-period fluctuations in the Company’s income. The increases or decreases in compensation expenses attributable to market price movements are reported in the operating expenses section of the consolidated statements of income. Because the obligations that must be settled only in Company common stock are treated as equity instruments, fluctuations in the market price of the underlying Company stock do not affect earnings. At December 31, 2023 and December 31, 2022 , the Company’s deferred compensation liability was $ 39,847,000 and $ 43,005,000 , respectively. In 2023 and 2022 , approximately 34 percent of deferred compensation liability represented deferred compensation tied to the performance of the Company’s common stock. The remainder of the deferred compensation liability was tied to the chosen mutual fund investment assets. A $ 1.00 increase in the market price of the Company’s common stock will result in approximately $ 143,000 of additional compensation expense. A $ 1.00 reduction in the market price of the common stock will reduce compensation expense by a like amount. The expense or income associated with the mutual fund component will generally fluctuate in line with the overall percentage increase or decrease of the U.S. stock markets. The mutual fund assets related to the deferred compensation plans are recorded on the Company’s balance sheet at cost when acquired and adjusted to their market values at the end of each reporting period. As allowed by generally accepted accounting principles, the Company elected the fair value option for recording the mutual fund investment assets. Therefore, market value changes for the mutual fund investment assets are recorded in the income statement in the same periods that the offsetting changes in the deferred compensation liabilities are recorded. Dividends, capital gains distributed by the mutual funds and realized and unrealized gains and losses related to mutual fund shares are recognized as investment income or loss in the other, net line of the consolidated statements of income. Fair Value Measurements GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Furthermore, GAAP establishes a framework, in the form of a three-level hierarchy, for measuring fair value that prioritizes the inputs to valuation techniques used to measure fair value. The following describes the hierarchy levels: Level 1 - quoted prices in active markets for identical assets and liabilities. Level 2 - inputs other than quoted prices included within Level 1 that are directly or indirectly observable for the asset or liability, such as quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data. Level 3 - unobservable inputs which reflect the entity’s own assumptions about the assumptions market participants use in pricing the assets and liabilities. The Company applies the fair value measurement provisions of GAAP to any of its financial assets and liabilities that are carried at fair value on the consolidated balance sheets (see Note 2, Fair Value Measurements , of the notes to the Company’s consolidated financial statements included in Item 8 of this Form 10-K), its outstanding debt for disclosure purposes (see Note 2, Fair Value Measurements , of the notes to the Company’s consolidated financial statements included in Item 8 of this Form 10-K) and its pension plan assets (see Note 13, Postretirement Benefit Plans , of the notes to the Company’s consolidated financial statements included in Item 8 of this Form 10-K). The Company also applies fair value measurements to nonfinancial assets and liabilities recorded in conjunction with business combinations and as part of impairment reviews for goodwill and other long-lived assets. Revenue Recognition The Company’s contracts typically have a single performance obligation that is satisfied at the time product is shipped and control passes to the customer. For a small portion of the business, performance obligations are deemed satisfied when product is delivered to a customer location. For arrangements where the Company consigns product to a customer location, revenue is recognized when the customer uses the inventory. The Company accounts for shipping and handling as activities to fulfill a promise to transfer a good. As such, shipping and handling fees billed to customers in a sales transaction are recorded in Net Sales and shipping and handling costs incurred are recorded in Cost of Sales. Volume and cash discounts due customers are estimated and recorded in the same period as the sales to which the discounts relate and are reported as reductions of revenue in the consolidated statements of income. See Note 21, Revenue from Contracts with Customers , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for more details. Cost of Sales Cost of sales is comprised of raw material costs (including inbound freight expense to deliver the raw materials), manufacturing plant labor expenses and various manufacturing overhead expenses, such as utilities, maintenance, operating supplies, amortization and manufacturing asset depreciation expenses. Cost of sales also includes outbound shipping and handling expenses, inter-plant transfer costs, warehouse expenses and rail car rental expenses. Operating Expenses Selling expenses are comprised of salaries and related fringe benefit expenses for marketing and sales personnel and operating costs, such as outside agent commissions, automobile rental and travel-related expenses, which support the sales and marketing functions. Bad debt charges and any depreciation expenses related to marketing assets (e.g., computers) are also classified as selling expenses. Administrative expenses are comprised of salaries and related fringe benefit expenses and operating costs for the Company’s various administrative functions, which include information technology, finance, legal, and human resources. The majority of environmental remediation expenses are also classified as administrative expense. The Company’s research and development costs are expensed as incurred. These expenses are aimed at the discovery of new knowledge with the intent that such effort will be useful in developing and commercializing a new product or in bringing about a significant improvement to an existing product or process. Total research and development expenses were $ 35,732,000 , $ 40,902,000 , and $ 38,778,000 in 2023, 2022 and 2021, respectively. The remainder of research, development and technical service expenses reflected on the consolidated statements of income relate to technical services, which include routine product testing, quality control and sales service support. Compensation expenses or income related to the Company’s deferred compensation plans is presented in the deferred compensation (income) expense line in the Consolidated Statements of Income. For more details, see Note 12, Deferred Compensation, of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K). Environmental Expenditures Environmental expenditures that relate to current operations are typically recorded in cost of sales. Expenditures that mitigate or prevent environmental contamination and that benefit future operations are capitalized as assets and depreciated on a straight-line basis over the estimated useful lives of the assets, which are typically 10 years. Estimated future expenditures that relate to an existing condition caused by past operations, and which do not contribute to current or future revenue generation, are recorded as liabilities, with the corresponding charge typically recorded in administrative expenses, when environmental assessments and/or remedial efforts are probable and the cost or range of possible costs can be reasonably estimated. When no amount within the range is a better estimate than any other amount, the minimum amount in the range is accrued. Estimating the possible costs of remediation requires making assumptions related to the nature and extent of contamination and the methods and resulting costs of remediation. Some of the factors on which the Company bases its estimates include information provided by feasibility studies, potentially responsible party negotiations and the development of remedial action plans. Legal costs related to environmental matters are expensed as incurred. See Note 16, Contingencies , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for environmental contingencies details. Goodwill and Other Intangible Assets The Company’s intangible assets include patents, trademarks, customer lists and relationships, technological and manufacturing know-how and goodwill, all of which were acquired as part of business or product line acquisitions. Intangible assets other than goodwill are determined to have either finite or indefinite useful lives. The Company currently has no indefinite-life intangible assets other than goodwill. The values for intangible assets with finite lives are amortized over the useful lives of the assets. Currently, the useful lives for the Company’s finite-lived intangible assets are as follows: patents – 15 years; trademarks – eight to 11 years ; customer relationships – ten to 20 years and know-how – seven to 20 years . In addition, finite-life intangible assets are tested for impairment when events or changes in circumstances indicate that the carrying value of an intangible asset may not be recoverable. Goodwill is not amortized but is tested for impairment at least annually, or more frequently, if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit to which goodwill relates below the reporting unit’s carrying value. See Note 4, Goodwill and Other Intangibles , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for detailed information about goodwill and other intangible assets. Income Taxes Income taxes are accounted for under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. Deferred tax assets are recognized to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, we consider all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If we determine that we would be able to realize our deferred tax assets in the future in excess of their net recorded amount, we would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. Uncertain tax positions are recorded in accordance with ASC 740, Income Taxes, on the basis of a two-step process whereby (1) we determine whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, we recognize the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within the income tax expense line in the accompanying Consolidated Statements of Income. Accrued interest and penalties are included within the related tax liability line in the Consolidated Balance Sheet. See Note 9, Income Taxes , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for more information about the Company’s income taxes. Translation of Foreign Currencies For the Company’s consolidated foreign subsidiaries whose functional currency is the local foreign currency, assets and liabilities are translated into U.S. dollars at exchange rates in effect at year end and revenues and expenses are translated at average exchange rates for the year. Any resulting translation adjustments are included within the consolidated balance sheets on the accumulated other comprehensive loss line of stockholders’ equity. Gains or losses on foreign currency transactions are reflected in the other, net line of the consolidated statements of income. The Company has four foreign subsidiaries whose functional currencies are the U.S. dollar. For these subsidiaries, nonmonetary assets and liabilities are translated at historical rates, monetary assets and liabilities are translated at exchange rates in effect at year end, revenues and expenses are translated at average exchange rates for the year and translation gains and losses are included in the other, net caption of the consolidated statements of income. Stock-Based Compensation The Company grants stock options, performance shares, time-based restricted stock units (RSUs) and stock appreciation rights (SARs) to certain employees under its incentive compensation plans. The Company calculates the fair values of stock options, performance shares, RSUs and SARs on the date such instruments are granted. The fair values of the stock options, performance shares and RSUs are then recognized as compensation expense over the vesting periods of the instruments. The Company’s SARs granted prior to 2015 were cash-settled and SARs granted in 2015 and later are stock-settled. All of the cash-settled SARs were exercised prior to the end of 2023. Compensation expense for the stock-settled SARs is calculated in the same way as compensation expense for stock options. See Note 11, Stock-based Compensation , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for detailed information about the Company’s stock-based compensation. Earnings Per Share Basic earnings per share amounts are computed as net income attributable to the Company divided by the weighted-average number of common shares outstanding. Diluted earnings per share amounts are based on the weighted-average number of common shares outstanding plus the weighted-average of net common shares (under the treasury stock method) that would be outstanding assuming the exercise of outstanding stock options and stock-settled SARs, the vesting of unvested RSUs that have no performance or market condition and the issuance of contingent performance shares. See Note 18, Earnings Per Share , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for detailed information about the Company’s earnings per share calculations. Comprehensive Income and Accumulated Other Comprehensive Income Comprehensive income includes net income and all other non-owner changes in equity that are not reported in net income. Comprehensive income is disclosed in the consolidated statements of comprehensive income. Accumulated other comprehensive income (AOCI) is reported as a component of stockholders’ equity in the Company’s consolidated balance sheets. See Note 19, Accumulated Other Comprehensive Income (Loss) , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for detailed information regarding changes in the Company’s AOCI and reclassifications out of AOCI to income. Segment Reporting The Company reports financial and descriptive information about its reportable operating segments. Operating segments are components of the Company that have separate financial information that is regularly evaluated by the chief operating decision maker to assess segment performance and allocate resources. The Company discloses segment revenue, operating income, assets, capital expenditures and depreciation and amortization expenses. Enterprise-wide financial information about the geographic locations in which the Company earns revenues and holds assets is also disclosed. See Note 17, Segment Reporting , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for detailed information about the Company’s segment reporting. Derivative Instruments Derivative instruments are recognized in the consolidated balance sheets as either assets or liabilities measured at fair value. For derivative instruments that are not designated as hedging instruments, changes in the fair values of the derivative instruments are recognized currently in earnings. For derivative instruments designated as hedging instruments, depending on the nature of the hedge, changes in the fair values of the derivative instruments are either offset in earnings against changes in the fair values of the hedged items or recognized in AOCI until the hedged transaction is recognized in earnings. At the time a hedging relationship is designated, the Company establishes the method it will use for assessing the effectiveness of the hedge and the measurement approach for determining the ineffective aspect of the hedge. Company policy prohibits the use of derivative instruments for trading or speculative purposes. See Note 3, Derivative Instruments , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for further information regarding the Company’s use of derivatives. At December 31, 2023 , the Company held open forward contracts for the purchase of 0.7 million dekatherms of natural gas in 2024 at a cost of $ 3,403,000 . The Company uses forward contracts to minimize its exposure to volatile natural gas prices. Because the Company anticipates taking delivery of the natural gas for use in its operations, the forward contracts qualify for the normal purchase exception provided under U.S. GAAP for derivative instruments. The Company has elected the exception for such contracts. As a result, the forward contracts are not accounted for as derivative instruments. The cost of natural gas is charged to expense at the time the natural gas is delivered and used. Recent Accounting Pronouncements In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848) Facilitation of the Effect of Reference Rate Reform on Financial Reporting. This update provides optional guidance for a limited period of time to ease the burden of implementing the usage of new reference rates. The amendments apply to contract modifications that replace a reference rate affected by reference rate reform and contemporaneous modifications of other contract terms related to the replacement of the reference rate. If elected, the o

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value Measurements	2. Fair Value Measurements The following were the financial instruments held by the Company at December 31, 2023 and 2022, and the methods and assumptions used to estimate the instruments’ fair values: Cash and cash equivalents Carrying value approximated fair value because of the short maturity of the instruments. Fair value of cash and cash equivalents is a Level 1 measurement. Derivative assets and liabilities Derivative assets and liabilities include the foreign currency exchange and interest rate swap contracts discussed in Note 3, Derivative Instruments , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K). Fair value and carrying value were the same because the contracts were recorded at fair value. The fair values of the foreign currency contracts were calculated as the difference between the applicable forward foreign exchange rates at the reporting date and the contracted foreign exchange rates multiplied by the contracted notional amounts. The fair value of the interest rate swaps was calculated as the difference between the contracted swap rate and the floating interest rate multiplied by the present value of the notional amount of the contract. The Company’s fair value measurements for derivative assets and liabilities fall within Level 2 of the fair value hierarchy. See the table that follows the financial instrument descriptions for the reported fair values of derivative assets and liabilities. Long-term investments Long-term investments include the mutual fund assets the Company held to fund a portion of its deferred compensation liabilities and all of its non-qualified supplemental executive defined contribution obligations. See the defined contribution plans section of Note 13, Postretirement Benefit Plans , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K). Fair value and carrying value were the same because the mutual fund assets were recorded at fair value in accordance with the FASB’s fair value option guidance. Fair values for the mutual funds were calculated using the published market price per unit at the reporting date multiplied by the number of units held at the reporting date and therefore its fair value measurements for mutual fund assets fall within Level 1 of the fair value hierarchy. See the table that follows the financial instrument descriptions for the reported fair value of long-term investments. Debt obligations The fair value of debt with original maturities greater than one year comprised the combined present values of scheduled principal and interest payments for each of the various loans, individually discounted at rates equivalent to those which could be obtained by the Company for new debt issues with durations equal to the average life to maturity of each loan. The fair values of the remaining Company debt obligations approximated their carrying values due to the short-term nature of the debt. The Company’s fair value measurements for debt fall in level 2 of the fair value hierarchy. At December 31, 2023 and 2022 , the fair values and related carrying values of debt, including current maturities, were as follows (the fair value and carrying value amounts are presented without regard to unamortized debt issuance costs of $ 895,000 and $ 686,000 as of December 31, 2023 and 2022, respectively): December 31 (In thousands) 2023 2022 Fair value $ 627,695 $ 541,029 Carrying value 655,041 587,826 The following tables present financial assets and liabilities, excluding cash and cash equivalents, measured on a recurring basis at fair value as of December 31, 2023 and 2022, and the level within the fair value hierarchy in which the fair value measurement falls: (In thousands) December 31, Level 1 Level 2 Level 3 Mutual fund assets $ 26,804 $ 26,804 $ — $ — Derivative assets: Interest rate contracts 6,183 — 6,183 — Foreign currency contracts 1,018 — 1,018 — Total assets at fair value $ 34,005 $ 26,804 $ 7,201 $ — Derivative liabilities: Foreign currency contracts $ 928 $ — $ 928 $ — (In thousands) December 31, Level 1 Level 2 Level 3 Mutual fund assets $ 23,294 $ 23,294 $ — $ — Derivative assets: Interest rate contracts 8,357 — 8,357 — Foreign currency contracts 513 — 513 — Total assets at fair value $ 32,164 $ 23,294 $ 8,870 $ — Derivative liabilities: Foreign currency contracts $ 525 $ — $ 525 $ —

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	3. Derivative Instruments The Company is exposed to certain risks relating to its ongoing business operations. The primary risk managed by the use of derivative instruments is foreign currency exchange risk. The Company holds forward foreign currency exchange contracts that are not designated as any type of accounting hedge as defined by U.S. generally accepted accounting principles. The Company uses these contracts to manage its exposure to exchange rate fluctuations on certain Company subsidiary cash, accounts receivable, accounts payable and other obligation balances that are denominated in currencies other than the entities’ functional currencies. The forward foreign exchange contracts are recognized on the balance sheet as either an asset or a liability measured at fair value. Gains and losses arising from recording the foreign exchange contracts at fair value are reported in earnings as offsets to the losses and gains reported in earnings arising from the re-measurement of the receivable and payable balances into the applicable functional currencies. At December 31, 2023 and 2022 , the Company had open forward foreign currency exchange contracts, all with durations of one to five months , to buy or sell foreign currencies with a U.S. dollar equivalent of $ 106,561,000 and $ 56,746,000 , respectively. The Company is currently exposed to volatility in short-term interest rates and has mitigated certain portions of that risk by using an interest rate swap. The interest rate swap is recognized on the balance sheet as either an asset or a liability measured at fair value. At December 31, 2023 , the Company held an interest rate swap contract with a notional value of $ 100,000,000 that was designated as a cash flow hedge. Period-to-period changes in the fair value of the interest rate swap are initially recognized as gains or losses in other comprehensive income. As the interest rate swap contract is settled, the corresponding gain or loss is reclassified out of accumulated other comprehensive income (AOCI) into earnings. The maturity date of the current interest swap contract is March 10, 2027 which is closely aligned with the June 24, 2027 maturity of the Company’s revolving credit facility. The fair values of the derivative instruments held by the Company on December 31, 2023, and December 31, 2022, are disclosed in Note 2, Fair Value Measurements , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K). Derivative instrument gains and losses for the years ended December 31, 2023, 2022 and 2021, were immaterial. For amounts reclassified out of AOCI into earnings for the years ended December 31, 2023, 2022 and 2021, see Note 19, Accumulated Other Comprehensive Income (Loss ), of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K).

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	4. Goodwill and Other Intangible Assets The changes in the carrying value of goodwill for the years ended December 31, 2023 and 2022, were as follows: Surfactants Polymer Specialty Products Total (In thousands) 2023 2022 2023 2022 2023 2022 2023 2022 Balance as of January 1 Goodwill $ 28,137 $ 25,689 $ 71,747 $ 74,482 $ 483 $ 483 $ 100,367 $ 100,654 Accumulated impairment loss ( 4,445 ) ( 3,467 ) — — — — ( 4,445 ) ( 3,467 ) Goodwill, net 23,692 22,222 71,747 74,482 483 483 95,922 97,187 Goodwill acquired (1) — 1,792 — — — — — 1,792 Goodwill impairment ( 1,060 ) ( 978 ) — — ( 483 ) — ( 1,543 ) ( 978 ) Foreign currency translation 1,644 656 1,419 ( 2,735 ) — — 3,063 ( 2,079 ) Balance as of December 31 Goodwill 29,781 28,137 73,166 71,747 483 483 103,430 100,367 Accumulated impairment loss ( 5,505 ) ( 4,445 ) — — ( 483 ) — ( 5,988 ) ( 4,445 ) Goodwill, net $ 24,276 $ 23,692 $ 73,166 $ 71,747 $ — $ 483 $ 97,442 $ 95,922 (1) See Note 20, Acquisitions , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for information regarding the goodwill acquired in a business combination. The Company typically tests its goodwill balances for impairment in the second quarter of each calendar year. Testing is completed more frequently when triggering events or changes in circumstances indicate it is more likely than not that the fair value of a reporting unit to which goodwill relates has declined below its carrying value. During the fourth quarter of 2023 the Company concluded that the goodwill related to its Specialty Products segment was impaired. The Specialty Products segment’s impairment resulted from the Company’s decision to exit portion of its Lipid Nutrition business. The Company recorded a non-cash charge of $ 483,000 in the Consolidated Statements of Income for the year ended December 31, 2023 on the Goodwill and other intangibles impairment line. The impairment charge equaled the entire balance of the Specialty Products operating segment’s goodwill. Also, during the fourth quarter of 2023 the Company concluded that the goodwill related to its Colombia reporting unit was impaired. The Colombia reporting unit is part of the Company’s Surfactant segment. The impairment relating to the Company’s Colombia reporting unit was recognized as a result of the reporting unit’s fair value declining below its carrying value. The Company estimates the fair value of each of its reporting units based on the average of market and income-based computations. During the fourth quarter of 2023 the Company recorded a non-cash charge of $ 1,060,000 in the Consolidated Statements of Income for the year ended December 31, 2023 on the Goodwill and other intangibles impairment line. The impairment charge equaled the entire balance of goodwill at the Company’s Colombia reporting unit. Goodwill impairments for Surfactants and Specialty Products segments were excluded from Surfactants and Specialty Products segment results. See Note 17, Segment Reporting , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for additional details. At December 31, 2023, the Company conducted additional goodwill testing for its Mexico reporting unit due to a decline in earnings. The decline in earnings was primarily due to a slow down in demand and significant customer and channel inventory destocking. At December 31, 2023, the goodwill related to the Mexico reporting unit was $ 6,652,000 . The Company used both market and income-based methodologies to assess the fair value of its Mexico reporting unit. Both approaches required the Company to make significant economic-related assumptions. Based on the Company’s testing, the fair value of the Mexico reporting unit was greater than its carrying value, and as a result, the Company did no t record any impairment charge as of December 31, 2023. The Company performed a sensitivity analysis on certain assumptions used in the valuation of its Mexico reporting unit as the fair value was not significantly in excess of the carrying value. Holding all other assumptions constant, a 100 basis point increase in the discount rate would not result in impairment nor would a 1.5 decrease in the multiple used in the market-based computation result in an impairment. During the second quarter of 2022 the Company completed its annual goodwill impairment testing and concluded that the goodwill related to its Philippines reporting unit was impaired. The Philippines reporting unit is part of the Company’s Surfactant segment. Goodwill impairment was recognized as a result of the reporting unit’s fair value declining below its carrying value. The Company estimates the fair value of each of its reporting units based on the average of market and income-based computations. The impairment relating to the Company’s Philippines reporting unit primarily resulted from lost market share at one major customer combined with higher unit overhead costs. The Company recorded a non-cash charge of $ 978,000 in the Consolidated Statements of Income for the year ended December 31, 2022. The impairment charge equaled the entire balance of the goodwill at the Company’s Philippines reporting unit. The following table presents the components of other intangible assets, all of which have finite lives, as of December 31, 2023 and 2022. The year-over-year changes in gross carrying values mainly resulted from the effects of foreign currency translation. Gross Carrying Value Accumulated December 31 (3) December 31 (3) (In thousands) 2023 2022 2023 2022 Other Intangible Assets: Patents $ 7,411 $ 7,411 $ 7,063 $ 6,363 Non-compete agreements (2) 401 635 401 548 Trademarks 11,662 11,384 6,705 5,346 Customer lists/relationships (2) 49,157 46,972 16,257 12,491 Know-how (1)(2) 29,543 28,908 15,177 12,536 Total $ 98,174 $ 95,310 $ 45,603 $ 37,284 (1) Know-how includes intellectual property rights covering proprietary information, written formulae, trade secrets or secret processes, inventions and devel opmental products (whether patentable or not), discoveries, improvements, compositions, manufacturing processes, manuals, specifications and technical data. (2) The 2022 balances include intangible assets acquired as part of the Company’s PerformanX acquisition in September 2022. See Note 20, Acquisitions , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for additional details. (3) The 2022 balances do not include gross carrying value and accumulated amortization amounts for intangibles assets that have been fully amortized in prior years. During the fourth quarter of 2023 the Company concluded that the patents related to its Specialty Products segment were impaired as a result of the Company’s decision to exit portions of its Lipid Nutrition business. The Company does not believe that the carrying value of these patents is recoverable. The Company recorded a non-cash charge of $ 495,000 in the Consolidated Statements of Income for the year ended December 31, 2023 on the Goodwill and other intangibles impairment line. Aggregate amortization expense for the years ended December 31, 2023, 2022 and 2021 , was $ 7,368,000 , $ 6,835,000 , and $ 7,292,000 , respectively. The Company typically recognizes amortization expense within the Cost of Sales line item on the income statement. Estimated amortization expense for identifiable intangibles assets for each of the five succeeding fiscal years is as follows: (In thousands) For year ended 12/31/24 $ 7,006 For year ended 12/31/25 6,566 For year ended 12/31/26 6,354 For year ended 12/31/27 6,354 For year ended 12/31/28 4,735

Inventories

Inventories	12 Months Ended
	Dec. 31, 2023
Inventory Disclosure [Abstract]
Inventories	5. Inventories The composition of inventories was as follows: December 31 (In thousands) 2023 2022 Finished products $ 184,828 $ 250,373 Raw materials 80,730 152,158 Total inventories $ 265,558 $ 402,531

Debt

Debt	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Debt	6. Debt At December 31, 2023 and 2022, debt was comprised of the following: (In thousands) Maturity December 31, December 31, Senior unsecured notes 3.95 % (net of unamortized debt issuance cost of $ 191 and 186 for 2023 and 2022, respectively) 2024 - 2027 $ 56,952 $ 71,243 3.86 % (net of unamortized debt issuance cost of $ 105 and 125 for 2023 and 2022, respectively) 2024 - 2025 28,466 42,732 4.86 % (net of unamortized debt issuance cost of $ 0 and 30 for 2023 and 2022 respectively) — — 9,260 2.30 % (net of unamortized debt issuance cost of $ 142 and 122 for 2023 and 2022, respectively) 2024 - 2028 49,858 49,878 2.37 % (net of unamortized debt issuance cost of $ 148 and 128 for 2023 and 2022, respectively) 2024 - 2028 49,852 49,872 2.73 % (net of unamortized debt issuance cost of $ 175 and 55 for 2023 and 2022, respectively) 2025 - 2031 99,825 99,945 2.83 % (net of unamortized debt issuance cost of $ 134 and 40 for 2023 and 2022, respectively) 2026 - 2032 74,866 74,960 Revolving credit facility and term loan borrowing 2024 - 2027 283,000 189,250 Debt of foreign subsidiaries Unsecured bank debt, foreign currency 2024 11,327 — Total debt $ 654,146 $ 587,140 Less current maturities 252,898 132,111 Long-term debt $ 401,248 $ 455,029 The Company’s long-term debt financing is currently comprised of certain senior unsecured notes issued to insurance companies in private placement transactions pursuant to note purchase agreements (the Note Purchase Agreements), totaling $ 359,819,000 as of December 31, 2023 . These notes are denominated in U.S. dollars and have fixed interest rates ranging from 2.30 percent to 3.95 percent. The notes had original maturities of seven to 12 years with mandatory principal payments beginning four, five and six years after issuance. The Company will be required to make principal payments on the currently outstanding notes from 2024 to 2032. On September 29, 2023, the Company entered into amendments to the Note Purchase Agreements (the NPA Amendments) to primarily provide additional covenant flexibility. The NPA Amendments, among other things, (i) amended the existing maximum net leverage ratios covenant; (ii) expanded the definition of “Qualified Cash,” a metric used to calculate the net leverage ratio, to include 65 percent of unrestricted and unencumbered foreign-based cash or permitted investments; and (iii) included a debt rating requirement and, to the extent the relevant notes are rated below investment grade, a rating fee of 0.75 percent per annum. The Company’s credit agreement (the Credit Agreement) with a syndicate of banks provides for credit facilities in an initial aggregate principal amount of $ 450,000,000 , consisting of (a) a $ 350,000,000 multi-currency revolving credit facility and (b) a $ 100,000,000 delayed draw term loan credit facility, each of which matures on June 24, 2027 . The Company maintains import letters of credit, and standby letters of credit under its workers’ compensation insurance agreements and for other purposes, as needed from time to time, which are issued under the revolving credit agreement. As of December 31, 2023 , the Company had outstanding letters of credit totaling $ 10,877,000 and $ 283,000,000 of outstanding borrowings under the credit agreement, inclusive of a $ 95,000,000 delayed-draw term loan ($ 5,000,000 of the term loan principal has been permanently repaid as scheduled). There was $ 151,123,000 available under the credit agreement as of December 31, 2023. Loans under the credit agreement may be incurred, at the discretion of the Company, with terms to maturity of one month , three months or six months . The Company may choose from two interest rate options: (1) Adjusted Term Secured Overnight Financing Rate (SOFR) applicable to USD loans and relevant benchmark rates applicable to EUR, GBP and CAD loans plus spreads ranging from 1.125 percent to 1.750 percent, depending on the Company’s net leverage ratio, or (2) the prime rate plus 0.125 percent to 0.750 percent, depending on the Company’s net leverage ratio. The credit agreement requires the Company to pay a commitment fee ranging from 0.125 percent to 0.250 percent per annum, which also depends on the Company’s net leverage ratio. The credit agreement requires the maintenance of certain financial ratios and compliance with certain other covenants that are similar to the Company’s existing debt agreements, including net worth, interest coverage, leverage financial covenants and limitations on restricted payments, indebtedness and liens. On September 29, 2023, the Company entered into an amendment (the Amendment) to the Credit Agreement. The Amendment amends the Credit Agreement to, among other things, (i) provide for a maximum net leverage ratio on substantially the same terms as the corresponding covenant contained in the NPA Amendments; and (ii) expand the definition of “Qualified Cash” to align with the definition of “Qualified Cash” included in the NPA Amendments. The Company’s foreign subsidiaries had $ 11,327,000 debt outstanding at December 31, 2023. The Company’s material debt agreements contain provisions which, among other covenants, require maintenance of certain financial ratios and place limitations on additional debt, investments and payment of dividends. Based on the loan agreement provisions that place limitations on dividend payments, unrestricted retained earnings (i.e., retained earnings available for dividend distribution) were $ 234,399,000 and $ 224,189,000 at December 31, 2023 and 2022, respectively. Debt at December 31, 2023 , matures as follows: $ 252,898,000 in 2024; $ 69,108,000 in 2025; $ 66,786,000 in 2026; $ 135,535,000 in 2027; $ 45,000,000 in 2028 and $ 85,714,000 after 2028. Debt maturing in 2024 includes $ 53,571,000 of scheduled repayments under long-term debt agreements. The Company’s foreign subsidiaries routinely have short-term working capital loans. These short-term loan agreements could be supplemented, if necessary, by the Company’s $ 350,000,000 revolving credit facility entered into on June 24, 2022. Net interest expense for the years ended December 31, 2023, 2022 and 2021, comprised the following: (In thousands) 2023 2022 2021 Interest expense $ 29,361 $ 17,852 $ 10,145 Interest income ( 3,843 ) ( 1,080 ) ( 1,255 ) 25,518 16,772 8,890 Capitalized interest ( 13,415 ) ( 6,963 ) ( 3,137 ) Interest expense, net $ 12,103 $ 9,809 $ 5,753

Leases

Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Leases	7. Leases The Company’s operating leases are primarily comprised of real estate, railcar, storage tank, warehouse, auto, trailer and manufacturing/office equipment leases. Real estate and railcars comprise approximately 52 percent and 33 percent, respectively, of the Company’s consolidated right of use (ROU) asset balance. Except for real estate, typical lease terms range from one to ten years . Real estate lease terms typically range from one to fifty years . The Company’s four principal real estate leases consist of the office lease for the corporate headquarters in Northbrook, Illinois and land leases in the Philippines, Singapore and Lake Providence, Louisiana. As of December 31, 2023 , the Company had railcars leases valued at approximately $ 292,000 , that had not commenced. These leases will commence during the first quarter of 2024 with lease term of seven years . As most of the Company’s leases do not provide an implicit borrowing rate, the Company uses its incremental borrowing rate (IBR) based on the information available at the commencement date in determining the present value of lease payments. IBRs were specifically determined for the United States, Philippines, Singapore, Brazil and China, typically for five-year increments. The U.S. IBR was used for all other countries as the leases in these countries are not material. The total value of leases that reside in the five countries identified above represents approximately 98 percent of the Company’s consolidated ROU asset balance. Lease cost is recognized in both the Cost of Sales and Operating Expenses sections of the Consolidated Statements of Income. (In thousands) Year ended December 31, 2023 Year ended December 31, 2022 Lease Cost Operating lease cost $ 17,820 $ 16,042 Short-term lease cost 10,786 7,029 Variable lease cost 2,354 1,206 Total lease cost $ 30,960 $ 24,277 Other Information Cash paid for amounts included in the Operating cash flow from operating $ 17,838 $ 15,963 Right-of-use assets obtained in exchange 12,134 7,588 The following table outlines maturities of lease liabilities as of December 31, 2023: (In thousands) Undiscounted Cash Flows: 2024 $ 16,105 2025 11,988 2026 9,201 2027 7,002 2028 6,063 Subsequent to 2028 34,555 Total Undiscounted Cash Flows $ 84,914 Less: Imputed interest ( 13,155 ) Present value $ 71,759 Current operating lease liabilities (1) 13,733 Non-current operating lease liabilities 58,026 Total lease liabilities $ 71,759 (1) This item is included in Accrued liabilities line on the Company’s Consolidated Balance Sheet. Weighted-average remaining lease term-operating leases 9 Years Weighted-average discount rate-operating leases 3.8 %

Other, Net

Other, Net	12 Months Ended
	Dec. 31, 2023
Other Income and Expenses [Abstract]
Other, Net	8. Other, Net Other, net in the Consolidated Statements of Income included the following for the years ended December 31, 2023, 2022 and 2021: (In thousands) 2023 2022 2021 Foreign exchange gains (losses) $ ( 3,703 ) $ ( 2,871 ) $ 501 Investment income 859 1,757 2,886 Realized and unrealized gains (losses) on investments 4,314 ( 8,188 ) 2,289 Net periodic benefit cost 28 690 302 Other retirement obligation 383 ( 212 ) 559 Gain on dissolution of the China joint venture — — 972 Other, net $ 1,881 $ ( 8,824 ) $ 7,509

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	9. Income Taxes The provisions for taxes on income and the related income before taxes for the years ended December 31, 2023, 2022 and 2021, were as follows: (In thousands) 2023 2022 2021 Taxes on Income Federal Current (1) $ ( 22,215 ) $ 39,328 $ 35,057 Deferred (1) 20,268 ( 20,636 ) ( 25,653 ) State Current (1) ( 1,188 ) 9,875 9,320 Deferred (1) 444 ( 6,943 ) ( 6,556 ) Foreign Current 13,287 19,799 23,870 Deferred ( 2,409 ) 127 ( 1,396 ) Total $ 8,187 $ 41,550 $ 34,642 Income before Taxes Domestic $ 11,693 $ 103,831 $ 77,696 Foreign 36,698 84,872 94,841 Total $ 48,391 $ 188,703 $ 172,537 (1) In 2023 for the 2022 U.S. tax returns (federal and state), a U.S. tax accounting method change was made for the 2018-2021 tax years and additional assets that qualified for bonus depreciation under IRC 168(k) were identified. Said items increased the income tax receivable with an offset to current tax expense and created deferred tax liabilities with an offset to deferred tax expense. These amounts were booked in 2023 as a provision-to-return adjustment. The variations between the effective and statutory U.S. federal income tax rates are summarized as follows: 2023 (1) 2022 2021 (In thousands) Amount % Amount % Amount % Federal income tax provision at statutory tax rate $ 10,162 21.0 $ 39,628 21.0 $ 36,233 21.0 State income tax provision, less applicable ( 588 ) ( 1.2 ) 2,316 1.2 2,184 1.3 Foreign income taxed at different rates 1,153 2.4 2,417 1.3 2,356 1.4 U.S. taxation of foreign earnings (2) 1,079 2.2 1,616 0.9 ( 134 ) ( 0.1 ) Unrecognized tax benefits (3) 4,090 8.5 3,324 1.8 1,775 1.0 Prior years return to provision true-up (4) ( 2,424 ) ( 5.0 ) ( 1,915 ) ( 1.0 ) ( 3,314 ) ( 1.9 ) Stock based compensation, excess tax benefits ( 1,262 ) ( 2.6 ) ( 580 ) ( 0.3 ) ( 1,287 ) ( 0.7 ) U.S. tax credits (5) ( 4,582 ) ( 9.5 ) ( 4,508 ) ( 2.4 ) ( 2,692 ) ( 1.6 ) Non-deductible expenses and other items, net 559 1.1 ( 748 ) ( 0.5 ) ( 479 ) ( 0.3 ) Total income tax provision $ 8,187 16.9 $ 41,550 22.0 $ 34,642 20.1 (1) In general, all permanent differences, whether positive or negative, have a more pronounced effect on the effective tax rate the lower the pre-tax income even if year-over-year the permanent differences did not change significantly. (2) Includes cost of global intangible low-taxed income (GILTI) in 2023, 2022 and 2021 plus other taxes paid or withheld on cash repatriated from foreign countries in 2023 and 2021. For 2023, see footnote below for the impact of repatriation withholding taxes. For 2023 and 2022, includes Subpart F activity. For 2021, includes the benefit of separate limitation loss foreign tax credit attributes, related to prior years, that were utilized in 2021. (3) For 2023, includes certain tax credits, transfer pricing, and the potential settlement of a foreign jurisdiction audit discussed below. (4) For 2023 and 2022, amount resulted from a higher federal research credit and lower GILTI. For 2021, amount resulted from a higher federal research credit, higher foreign-derived intangible income (FDII), and lower GILTI. (5) For 2023 and 2022, the increase was partially due to certain pilot model design and engineering costs. At December 31, 2023 and 2022, the tax effects of significant temporary differences representing deferred tax assets and liabilities were as follows: (In thousands) 2023 2022 Deferred Tax Assets: Pensions $ 446 $ 144 Deferred revenue 2,640 3,483 Other accruals and reserves 14,638 13,949 Legal and environmental accruals 7,292 10,283 Deferred compensation 12,199 13,845 Bad debt and rebate reserves 4,916 3,729 Non-U.S. subsidiaries net operating loss carryforwards 6,512 3,634 Amortization of intangibles 37,123 28,311 Inventories 8,959 10,577 Tax credit carryforwards 13,682 8,183 $ 108,407 $ 96,138 Deferred Tax Liabilities: Depreciation $ ( 82,907 ) $ ( 52,130 ) Unrealized foreign exchange loss ( 2,784 ) ( 3,603 ) Other ( 2,991 ) ( 3,064 ) $ ( 88,682 ) $ ( 58,797 ) Valuation Allowance $ ( 853 ) $ ( 836 ) Net Deferred Tax Assets $ 18,872 $ 36,505 Reconciliation to Consolidated Balance Sheet: Non-current deferred tax assets (in other non-current assets) 29,245 46,684 Non-current deferred tax liabilities ( 10,373 ) ( 10,179 ) Net Deferred Tax Assets $ 18,872 $ 36,505 Earnings generated by a foreign subsidiary are presumed to ultimately be transferred to the parent company. Therefore, the establishment of deferred taxes may be required with respect to the excess of the investment value for financial reporting over the tax basis of investments in those foreign subsidiaries (also referred to as book-over-tax outside basis differences). A company may overcome this presumption and forgo recording a deferred tax liability in its financial statements if it can assert that management has the intent and ability to indefinitely reinvest the earnings of its foreign subsidiaries. Pursuant to the 2017 U.S. Tax Cuts and Jobs Act (Tax Act), the Company’s foreign earnings have been subject to U.S. federal taxes. The Company now has the ability to repatriate to the U.S. parent the cash associated with these foreign earnings with little additional U.S. federal taxes. This cash may, however, be subject to foreign income and/or local country taxes if repatriated to the United States. In addition, repatriation of some foreign cash balances may be further restricted by local laws. As such, the Company intends to limit its distributions to earnings previously taxed in the U.S. or earnings that would qualify for the 100 percent dividends received deduction provided for in the Tax Act as long as such distributions would not result in any significant foreign taxes. In 2023, the Company repatriated $ 54,944,000 between July and December from its Netherlands, Singapore, and Canada subsidiaries. The Company incurred an incremental tax expense of $ 397,000 as a result of this repatriation. The effect of the adjustment on the 2023 effective tax rate was an increase of approximately 0.8 percent. In 2022, the Company did not repatriate any cash to the U.S. parent company. The Company evaluated its indefinite reinvestment assertion with regards to certain accumulated foreign earnings as of December 31, 2023. The Company does not consider the undistributed earnings of its Canadian subsidiary to be indefinitely reinvested in foreign operations to the extent of the subsidiary’s paid-up capital (PUC) as determined under Canadian tax law which is used to determine tax-free distributions for Canadian tax purposes. The Company also does not consider the undistributed earnings of one of its Dutch subsidiaries, and one of its Singapore subsidiaries to be indefinitely reinvested in foreign operations. A distribution from any of these subsidiaries should not result in any significant foreign taxes to the extent of the distribution limitations discussed above and therefore, the Company has not recognized a deferred tax liability for these undistributed earnings as of December 31, 2023. The Company considers the undistributed earnings of its remaining foreign subsidiaries to be indefinitely reinvested in foreign operations. At this time, the determination of deferred tax liabilities on this amount is not practicable. The Company had non-U.S. tax loss carryforwards of $ 20,113,000 (pretax) as of December 31, 2023, and $ 10,754,000 as of December 31, 2022, that are available for use by the Company between 2024 and 2033. The Company had tax credit carryforwards of $ 13,682,000 as of December 31, 2023, and $ 8,183,000 as of December 31, 2022, that are available for use by the Company between 2024 and 2043. The Company had non-U.S. capital loss carryforwards of $ 608,000 as of December 31, 2023, and $ 595,000 as of December 31, 2022. The Company’s capital loss carryforwards do not expire. As of December 31, 2023 and 2022, the Company had valuation allowances of $ 853,000 and $ 836,000 , respectively, which were attributable to deferred tax assets in Canada, India, the Philippines and Singapore. The realization of deferred tax assets is dependent on the generation of sufficient taxable income in the appropriate tax jurisdictions. The Company believes that it is more likely than not that the related deferred tax assets will not be realized. As of December 31, 2023, 2022 and 2021, unrecognized tax benefits totaled $ 14,590,000 , $ 10,682,000 and $ 7,292,000 , respectively. The amount of unrecognized tax benefits that, if recognized, would favorably affect the Company’s effective income tax rate in any future periods, net of the federal benefit on state issues, was approximately $ 14,056,000 , $ 10,172,000 and $ 6,973,000 at December 31, 2023, 2022 and 2021, respectively. The Company does not believe that the amount of unrecognized tax benefits related to its current uncertain tax positions will change significantly over the next 12 months. The Company recognizes accrued interest and penalties related to unrecognized tax benefits as income tax expense. In 2023, the Company recognized net interest and penalty expense of $ 435,000 compared to $ 202,000 of net interest and penalty expense in 2022 and $ 260,000 of net interest and penalty expense in 2021. At December 31, 2023 the liability for interest and penalties was $ 978,000 compared to $ 543,000 at December 31, 2022. The Company files income tax returns in the U.S. federal jurisdiction and various states and foreign jurisdictions. The Company is not subject to U.S. federal income tax examinations by tax authorities for years before 2016. Some foreign jurisdictions and various U.S. states jurisdictions may be subject to examination back to 2016. During 2021, the Internal Revenue Service started its audit of the 2016-2019 tax years and expanded the years under audit to 2016-2020 in 2022. As of December 31, 2023, this audit was still open, and the Company had not been notified of any significant proposed adjustments. Below are reconciliations of the January 1 and December 31 balances of unrecognized tax benefits for 2023, 2022 and 2021: (In thousands) 2023 2022 2021 Unrecognized tax benefits, opening balance $ 10,682 $ 7,292 $ 4,735 Gross increases – tax positions in prior period 1,891 2,188 938 Gross increases – current period tax positions 2,139 1,617 1,662 Settlements/State voluntary disclosure ( 343 ) ( 454 ) — Foreign currency translation 241 74 ( 14 ) Lapse of statute of limitations ( 20 ) ( 35 ) ( 29 ) Unrecognized tax benefits, ending balance $ 14,590 $ 10,682 $ 7,292

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Stockholders' Equity	10. Stockholders’ Equity At December 31, 2023 and 2022 , treasury stock consisted of 4,628,072 and 4,605,858 shares of common stock, respectively. During 2023 , no shares of Company common stock were purchased in the open market. In addition, 42,662 shares were surrendered to the Company in connection with the settlement of employees’ minimum statutory withholding taxes related to performance stock awards, exercised SARs and deferred compensation distributions. Also, 20,448 shares of treasury stock were distributed to participants under the Company’s deferred compensation plans.

Stock-based Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-based Compensation	11. Stock-based Compensation On December 31, 2023 , the Company had outstanding stock options, performance shares, RSUs and SARs awarded under its 2011 Incentive Compensation Plan (2011 Plan) and 2022 Equity Incentive Compensation Plan (2022 Plan). Equity incentive awards are granted to Company executives and other key employees. In addition, stock awards are granted to non-employee directors of the Company. As of April 26, 2022, no additional stock options, performance shares, RSUs or SARs may be granted under the 2011 Plan. As of the effective date of the 2022 Plan, 500,000 shares of the Company’s common stock, plus the number of shares that remained available for awards under the 2011 Plan as of April 26, 2022, were available for equity awards under the 2022 Plan. At December 31, 2023 , there were 716,012 shares available for grant under the 2022 Plan. Compensation expense recorded in the consolidated statements of income for all plans was $ 5,741,000 , $ 13,851,000 , and $ 11,716,000 for the years ended December 31, 2023, 2022 and 2021, respectively. The decrease in stock-based compensation expense in 2023 versus 2022 was primarily attributable to the Company not achieving threshold net income performance levels for performance shares granted in 2023 and such performance shares being forfeited; and the non-recurrence of accelerated vesting in 2022 of certain equity grants for the Company’s former Chief Executive Officer, who retired on April 25, 2022. The total income tax benefit recognized in the income statement for share-based compensation arrangements was $ 1,452,000 , $ 3,537,000 , and $ 2,867,000 for the years ended December 31, 2023, 2022 and 2021, respectively. Stock Options Stock option awards are granted with an exercise price equal to the market price of the Company’s stock at the date of grant. The market price is defined and calculated as the average of the opening and closing prices for Company common stock on the grant date as reported in the New York Stock Exchange – Composite Transactions. Stock option awards granted prior to 2017 generally cliff vested after two years . Starting in 2017, stock options have a three-year graded vesting feature, with one-third of the award vesting each year. The Company has elected the straight-line method of expense attribution for the stock options with graded vesting feature. These options have a 10 -year contractual term. The fair value of each option award was estimated on the date of grant using the Black-Scholes option valuation model incorporating the weighted-average assumptions noted in the following table. Expected volatility is based on the historical volatility of the Company’s common stock. The Company also uses historical data to estimate the expected term of options granted. The risk-free rate is the U.S. Treasury note rate that corresponds to the expected option term at the date of grant. The following are the weighted-average assumptions used to calculate the grant-date fair values of stock option awards granted in the years ended December 31, 2023, 2022 and 2021: For the Years Ended December 31 2023 2022 2021 Expected dividend yield 1.19 % 1.18 % 1.30 % Expected volatility 31.29 % 32.27 % 31.81 % Expected term 7.2 years 6.0 years 7.3 years Risk-free interest rate 4.03 % 1.93 % 0.96 % A summary of stock option activity for the year ended December 31, 2023 is presented below: Shares Weighted- Weighted- Aggregate Value Options Outstanding at January 1, 2023 427,161 $ 82.53 Granted 2,777 106.85 Exercised ( 52,999 ) 54.24 Forfeited ( 8,800 ) 113.81 Outstanding at December 31, 2023 368,139 86.03 4.72 $ 3,135 Vested or expected to vest at December 31, 2023 368,139 86.03 4.72 3,135 Exercisable at December 31, 2023 363,949 85.79 4.68 3,186 The weighted-average grant-date fair values of options awarded during the years ended December 31, 2023, 2022 and 2021 , were $ 38.72 , $ 32.21 , and $ 36.49 , respectively. The total intrinsic values of options exercised during the years ended December 31, 2023, 2022, and 2021 were $ 2,364,000 , $ 475,000 , and $ 1,287,000 , respectively. As of December 31, 2023 , the total unrecognized compensation cost for unvested stock options was $ 127,000 . That cost is expected to be recognized over a weighted-average period of 1.7 years. Cash received from stock option exercises under the Company’s stock option plans for the years ended December 31, 2023, 2022, and 2021 was $ 2,795,000 , $ 782,000 , and $ 1,369,000 , respectively. The actual tax benefit realized for the tax deductions from stock option exercises totaled $ 330,000 , $ 36,000 , and $ 172,000 for the years ended December 31, 2023, 2022 and 2021, respectively. Stock Awards In 2021 and 2022, the Company granted stock awards under the 2011 Plan and, starting in April 2022, the Company also granted stock awards under the 2022 Plan. The Company grants stock awards to employees in the form of performance shares and RSUs. The performance shares vest only upon the Company’s achievement of certain levels of financial performance in specified measurement periods as approved by the Human Capital and Compensation Committee of the Board of Directors. The number of shares of the Company’s common stock ultimately distributed, if any, is contingent upon the Company’s actual financial performance attained in the measurement period relative to the targets approved by the Human Capital and Compensation Committee. The fair value of performance shares equals the grant-date market price of the Company’s common stock, discounted for the estimated amount of dividends that would not be received during the measurement period. Compensation expense is recorded each reporting period based on the probable number of awards that will ultimately vest given the projected level of financial performance. If during the measurement period certain threshold performance objectives are not met, no compensation cost is recognized and any compensation expense recorded in prior periods is reversed. The RSUs have no performance conditions associated with their vesting and vest after the period of service established for the given grant. In addition, the Company grants stock awards that have no performance or service conditions associated with their vesting to non-employee directors of the Company. A summary of stock award activity for the year ended December 31, 2023, is presented below: Shares Weighted-Average Stock Awards Unvested at January 1, 2023 103,969 $ 110.50 Granted 88,130 104.96 Vested ( 29,906 ) 116.41 Forfeited/modified due to change of assumptions ( 95,407 ) 106.68 Unvested at December 31, 2023 66,786 106.00 The weighted-average grant-date fair values of stock awards granted during the years ended December 31, 2023, 2022 and 2021 , were $ 104.96 , $ 106.78 , and $ 119.76 , respectively. As of December 31, 2023 , under the Company’s current assumption as to the number of shares of stock awards that will vest at the measurement periods ended December 31, 2024 and 2025, there was $ 3,761,000 of unrecognized compensation cost for unvested stock awards. That cost is expected to be recognized over a period of 1.7 years. SARs At December 31, 2023 , the Company had stock-settled SARs outstanding. SARs granted prior to 2017 cliff vested after two years . Starting in 2017, SARs have a three-year graded vesting feature, with one-third of the awards vesting each year. The Company has elected the straight-line method of expense attribution for the SARs with graded vesting feature. All SARs expire ten years from the grant date. Upon the exercise of a SARs award, a participant receives Company common stock. For stock-settled SARs, the number of shares equals the excess of the fair market value of a total number of shares/SARs exercised at the date of exercise over the fair market value of a total number of shares/SARs exercised at the date of grant (the exercise price) divided by the fair market value of a share of Company common stock at the date of exercise. Compensation expense for stock-settled SARs is based on the grant-date value of the awards allocated over the proportion of the vesting period that has been completed at the reporting date. The following is a summary of SARs activity for the year ended December 31, 2023: Shares Weighted- Weighted- Aggregate SARs Outstanding at January 1, 2023 850,156 $ 94.49 Granted 77,006 108.64 Exercised ( 38,988 ) 61.97 Forfeited ( 56,255 ) 112.46 Outstanding at December 31, 2023 831,919 96.11 5.94 $ — The weighted-average grant-date fair values of SARs granted during the years 2023, 2022 and 2021 were $ 38.98 , $ 34.76 , and $ 36.49 , respectively. The fair value for each SARs award was estimated using the Black-Scholes valuation model incorporating the same assumptions as noted for stock options. At December 31, 2023 , there was $ 3,648,000 of total unrecognized compensation cost related to all unvested SARs. That cost is to be recognized over a weighted-average period of 1.6 years. In general, it is the Company’s policy to issue new shares of its common stock upon the exercise of stock options and stock-settled SARs or the vesting of performance shares and RSUs.

Deferred Compensation

Deferred Compensation	12 Months Ended
	Dec. 31, 2023
Compensation Related Costs [Abstract]
Deferred Compensation	12. Deferred Compensation The Company sponsors deferred compensation plans that allow management employees to defer receipt of their annual cash incentive compensation and performance shares and outside directors to defer receipt of their fees and stock awards until retirement, departure from the Company or as otherwise elected. Compensation expense and the related deferred compensation obligation are recorded when the underlying compensation is earned. Over time, the deferred obligation may increase or decrease based on the performance results of investment options chosen by the plan participants. The investment options include the Company’s common stock and a limited selection of mutual funds. The Company maintains sufficient shares of treasury stock to cover the equivalent number of shares that result from participants’ elections of the Company common stock investment option. As a result, the Company periodically purchases shares of its common stock in the open market or in private transactions. The Company purchases shares of the applicable mutual funds to fund the portion of its deferred compensation liabilities tied to such investments. Some plan distributions may be made in cash or Company common stock at the option of the participant. Other plan distributions can only be made in Company common stock. For deferred compensation obligations that may be settled in cash or shares of Company’s common stock at the option of the participant, the Company must record appreciation in the market values of the investment choices made by participants as additional compensation expense. Conversely, declines in the market values of the investment choices reduce compensation expense. Increases and decreases of compensation expense that result from fluctuations in the underlying investments are recorded as part of operating expenses in the consolidated statements of income. The obligations that must be settled only in shares of the Company’s common stock are treated as equity instruments; therefore, fluctuations in the market price of the underlying shares of the Company’s common stock do not affect earnings. The additional compensation expense or income resulting from the changes in the market values and earnings of the selected investment options was $ 4,371,000 expense in 2023 , $ 9,393,000 income in 2022 and $ 6,895,000 expense in 2021. The main factors in the increase of the 2023 deferred compensation expense versus 2022 deferred compensation income was an increase in the value of the mutual fund investment assets, partially offset by an $ 11.91 per share decrease in the market price of the Company’s common stock during 2023. The Company’s deferred compensation liability was $ 39,847,000 and $ 43,005,000 at December 31, 2023 and 2022 , respectively.

Postretirement Benefit Plans

Postretirement Benefit Plans	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Postretirement Benefit Plans	13. Postretirement Benefit Plans Defined Benefit Plans The Company sponsors various funded qualified and unfunded non-qualified defined benefit pension plans, the most significant of which cover employees in the U.S. and U.K. locations. The various U.S. defined benefit pension plans were amended during the years 2005-2008 to freeze the plans by stopping the accrual of service benefits. The U.K. defined benefit pension plan was frozen in 2006. Benefits earned through the freeze dates are available to participants when they retire, in accordance with the terms of the plans. The Company established defined contribution plans to replace the frozen defined benefit pension plans. Obligations and Funded Status at December 31 United States United Kingdom (In thousands) 2023 2022 2023 2022 Change in benefit obligation Benefit obligation at beginning of year $ 130,467 $ 174,863 $ 13,286 $ 23,276 Interest cost 6,949 4,923 669 374 Actuarial (income) loss 3,634 ( 40,420 ) ( 92 ) ( 7,333 ) Benefits paid ( 9,267 ) ( 8,899 ) ( 804 ) ( 709 ) Foreign exchange impact — — 691 ( 2,322 ) Benefit obligation at end of year $ 131,783 $ 130,467 $ 13,750 $ 13,286 United States United Kingdom (In thousands) 2023 2022 2023 2022 Change in plan assets Fair value of plan assets at beginning of year $ 136,744 $ 178,574 $ 15,163 $ 27,464 Actual return on plan assets 10,237 ( 33,187 ) 470 ( 9,393 ) Employer contributions 271 256 464 536 Benefits paid ( 9,267 ) ( 8,899 ) ( 804 ) ( 709 ) Foreign exchange impact — — 798 ( 2,735 ) Fair value of plan assets at end of year $ 137,985 $ 136,744 $ 16,091 $ 15,163 Over funded status at end of year $ 6,202 $ 6,277 $ 2,341 $ 1,877 The amounts recognized in the consolidated balance sheets at December 31 consisted of: United States United Kingdom (In thousands) 2023 2022 2023 2022 Non-current assets $ 8,627 $ 8,700 $ 2,341 $ 1,877 Current liability ( 308 ) ( 278 ) — — Non-current liability ( 2,117 ) ( 2,145 ) — — Net amount recognized $ 6,202 $ 6,277 $ 2,341 $ 1,877 The amounts recognized in accumulated other comprehensive income at December 31 consisted of: United States United Kingdom (In thousands) 2023 2022 2023 2022 Net actuarial loss $ 20,755 $ 18,801 $ 5,989 $ 6,188 At December 31, 2023 and 2022 there were no pension plans with projected benefit obligations in excess of plan assets. Components of Net Periodic Benefit Cost and Other Amounts Recognized in Other Comprehensive Income Net periodic benefit costs for the years ended December 31, 2023, 2022 and 2021, were as follows: United States United Kingdom (In thousands) 2023 2022 2021 2023 2022 2021 Interest cost $ 6,949 $ 4,923 $ 4,671 $ 669 $ 374 $ 357 Expected return on plan assets ( 8,533 ) ( 8,802 ) ( 10,348 ) ( 695 ) ( 399 ) ( 320 ) Amortization of net actuarial (gain) loss ( 23 ) 2,277 4,444 334 9 129 Net periodic benefit cost $ ( 1,607 ) $ ( 1,602 ) $ ( 1,233 ) $ 308 $ ( 16 ) $ 166 Other changes in plan assets and benefit obligations recognized in other comprehensive income for the years ended December 31, 2023, 2022 and 2021, were as follows: United States United Kingdom (In thousands) 2023 2022 2021 2023 2022 2021 Net actuarial (gain) loss $ 1,930 $ 1,570 $ ( 9,793 ) $ 135 $ 2,430 $ ( 757 ) Amortization of net actuarial gain (loss) 23 ( 2,277 ) ( 4,444 ) ( 334 ) ( 9 ) ( 129 ) Total recognized in other comprehensive $ 1,953 $ ( 707 ) $ ( 14,237 ) $ ( 199 ) $ 2,421 $ ( 886 ) Total recognized in net periodic benefit $ 346 $ ( 2,309 ) $ ( 15,470 ) $ 109 $ 2,405 $ ( 720 ) Estimated Future Benefit Payments (In thousands) United United 2024 $ 9,646 $ 606 2025 9,841 628 2026 10,023 671 2027 10,126 698 2028 10,158 733 2029-2033 49,888 4,116 Assumptions The weighted-average assumptions used to determine benefit obligations at December 31 were as follows: United States United Kingdom 2023 2022 2023 2022 Discount rate 5.20 % 5.50 % 4.80 % 5.00 % The weighted-average assumptions used to determine net periodic benefit costs for years ended December 31 were as follows: United States United Kingdom 2023 2022 2021 2023 2022 2021 Discount rate 5.50 % 2.90 % 2.60 % 5.00 % 1.80 % 1.40 % Expected long-term return on plan assets 5.50 % 5.50 % 6.75 % 4.47 % 1.61 % 1.13 % In addition to the above assumptions, the Company uses a market-related value of assets approach to calculate the expected return on the plan assets component of U.S. net periodic benefit cost. The market-related value equals the fair value of plan assets with five-year smoothing of asset gains or losses. Asset gains are subtracted or losses added in the following way: 80 percent of the prior year’s gain or loss; 60 percent of the second preceding year’s gain or loss; 40 percent of the third preceding year’s gain or loss; and 20 percent of the fourth preceding year’s gain or loss. Gains or losses for the year are calculated as the difference between the expected fair value of assets and the actual fair value of assets. Investment Strategies and Policies U.S. Plans During 2023 the plan reduced equity exposure and increased bond holdings as part of an on-going de-risking strategy. Plan equity assets (other than Stepan Company stock) are invested using domestic and foreign exchange traded funds (ETFs) to achieve diversification amongst a relatively small asset pool. An investment management firm monitors the ETFs and also monitors and manages the overall asset allocation and compliance with the Investment Policy Statement. The fixed income manager seeks to reduce the volatility of the plan’s funded status by matching the duration with the plan’s liability while seeking to improve returns through security selection, sector allocation and yield curve management. Risk is diversified among multiple asset categories. The investment management firm recommends asset allocations based on the time horizon available for investment, funded status, the nature of the plan cash flows and liabilities and other factors. The asset allocation targets are approved by the Company’s Plan Committee. Available investment categories include: Equities: Common stocks of large, medium, and small companies, including both U.S. and non-U.S. based companies. The long-term target allocation for equities, excluding Company stock, is approximately 13 percent and the total equity target is 20 percent, including allocation to the Company’s common stock. Fixed Income (Debt): Bonds or notes issued or guaranteed by the U.S. government, and to a lesser extent, by non-U.S. governments, or by their agencies or branches, mortgage-backed securities, including collateralized mortgage obligations, corporate bonds, municipal bonds and dollar-denominated debt securities issued in the U.S. by non-U.S. banks and corporations. A small percentage of the fixed income assets may be in debt securities that are below investment grade. The target allocation for fixed income is 78 percent. The fixed income portfolio has a duration similar to the plan’s liability stream and is designed to perform consistent with the movement of the plan’s liabilities. Employer Securities: The retirement plans also hold shares of the Company’s common stock, which are purchased or sold by the trustee from time to time, as directed by the Plan Committee. At the direction of the Plan Committee, the plans sold 38,542 shares of the Company’s common stock to the Company’s employee stock ownership plan (ESOP) trust on February 15, 2023. In 2022 , the plans sold 33,983 shares to the Company’s ESOP trust on February 17, 2022. In 2021 , the plans sold 31,362 shares to the Company’s ESOP trust on February 24, 2021. The target allocation for cash is two percent of plan assets. U.K. Plan The objective of the U.K. defined benefit pension fund investment strategy is to maximize the long-term rate of return on plan assets within a medium level of risk in order to minimize the cost of providing pension benefits. To that end, the plan assets are invested in an actively managed pooled fund of funds that diversifies its holdings among equity securities, debt securities, property and cash. Although there are no formal target allocations for the plan assets, the overall strategy is to achieve a mix of investments for long-term growth and near-term benefit payments with a wide diversification of asset types. Equity securities are selected from U.K., European, U.S. and emerging market companies. Bonds include U.K. and other countries’ government notes and corporate debt of U.K and non-U.K. companies. There are no specific prohibited investments. Plan trustees meet regularly with the fund manager to assess the fund’s performance and to reassess investment strategy. At December 31, 2023 , the pension asset allocation was six percent equities, one percent real estate, 80 percent bonds, five percent insurance contracts, and eight percent cash. Included in plan assets are insurance contracts purchased by the plan trustees to provide pension payments for specific retirees. In past years, at the time a plan participant retired, the plan trustee would periodically purchase insurance contracts to cover the future payments due the retiree. This practice is no longer followed. The contracts are revocable, and the related plan obligations are not considered settled. Therefore, the plan assets and obligations include the insured amounts. Plan Assets U.S. Plans The Company’s asset allocations for its U.S. pension plans at December 31, 2023 and 2022, by asset category, were as follows: December 31, 2023 (In thousands) Level 1 Level 2 Level 3 Total Cash and Cash Equivalents $ 8,196 $ — $ — $ 8,196 Equity Securities U.S. Equities 14,942 — — 14,942 Non-U.S. Equities — — — — Employer Securities 12,316 — — 12,316 Total Equities 27,258 — — 27,258 Fixed Income Securities U.S. Corporate Bonds — 57,595 — 57,595 U.S. Government and Agency Bonds 30,278 3,533 — 33,811 Other Bonds — 11,125 — 11,125 Total Fixed Income 30,278 72,253 — 102,531 Total $ 65,732 $ 72,253 $ — $ 137,985 December 31, 2022 (In thousands) Level 1 Level 2 Level 3 Total Cash and Cash Equivalents $ 7,531 $ — $ — $ 7,531 Equity Securities U.S. Equities 21,279 — — 21,279 Non-U.S. Equities 9,788 — — 9,788 Employer Securities 17,970 — — 17,970 Total Equities 49,037 — — 49,037 Fixed Income Securities U.S. Corporate Bonds — 51,444 — 51,444 U.S. Government and Agency Bonds 15,627 2,628 — 18,255 Other Bonds — 10,477 — 10,477 Total Fixed Income 15,627 64,549 — 80,176 Total $ 72,195 $ 64,549 $ — $ 136,744 Plan Asset Valuation Methodology Following is a description of the valuation methodologies used for plan assets measured at fair value. Individual equity securities, including employer securities, are valued by Standard & Poor’s Securities Evaluations as determined by quoted market prices on the New York Stock Exchange or other active trading markets. Both market pricing and future cash flow analysis may be used in the pricing process as follows: Level 1 – Equities are valued according to the exchange-quoted market prices of the underlying investments. Level 1 fixed income securities are U.S. government securities and are valued according to quoted prices from active markets. Level 2 – Fixed income investments without equivalent trading exchanges are valued primarily through a technique known as “future cash flow approach” which is based on what bondholders can reasonably expect to receive based upon an issuer’s current financial condition. Pricing analysts prepare cash flow forecasts and utilize one or two pricing models to arrive at an evaluated price. These models include factors such as the interest rate on the coupon, maturity, rating, cash flow projections and other factors. Level 3 – no investments held during 2023 or 2022 were categorized as Level 3. U.K. Plan The Company’s asset allocations for its U.K. pension plans at December 31, 2023 and 2022, by asset category, were as follows: December 31, 2023 (In thousands) Level 1 Level 2 Level 3 Total Cash — $ 1,308 $ — $ 1,308 Equity Securities Pooled Pension Funds — 1,017 — 1,017 Fixed Income Pooled Pension Funds — 12,860 — 12,860 Real Estate Pooled Pension Funds — 146 — 146 Insurance Contracts — — 760 760 Total $ — $ 15,331 $ 760 $ 16,091 December 31, 2022 (In thousands) Level 1 Level 2 Level 3 Total Cash $ — $ 1,448 $ — $ 1,448 Equity Securities Pooled Pension Funds — 1,688 — 1,688 Fixed Income Pooled Pension Funds — 11,350 — 11,350 Insurance Contracts — — 677 677 Total $ — $ 14,486 $ 677 $ 15,163 Units of each of the pooled funds are valued by the trustee based on quoted market prices of the underlying investments (the underlying assets are either exchange traded or have readily available markets). Fair value changes within asset categories for which fair value measurements use significant unobservable inputs (Level 3) were as follows during 2023 and 2022: (In thousands) Insurance Contracts Fair value, December 31, 2021 $ 1,003 Sale proceeds (benefit payments) ( 104 ) Change in unrealized gain ( 120 ) Foreign exchange impact ( 102 ) Fair value, December 31, 2022 $ 677 Sale proceeds (benefit payments) ( 123 ) Change in unrealized gain 169 Foreign exchange impact 37 Fair value, December 31, 2023 $ 760 Long-term Rate of Return for Plan Assets U.S. Plans The overall expected long-term rate of return on assets of 5.50 percent that was used to develop the 2023 pension expense is based on plan asset allocation, capital markets forecasts and expected benefits of active investment management. For fixed income, the expected return is 5.35 percent. This assumption includes the yield on the five-year zero-coupon U.S. Treasury bond as the base rate along with historical data from the U.S. Treasury yield curve. For equities, the expected return is 9.57 percent for U.S. and international equities. This return is based on a blended average of three different statistical models that each incorporates multiple factors, including forecasts relating to inflation, Gross Domestic Product, and the Fed Funds Target Rate. The overall investment return forecast reflects the target allocations and the capital markets forecasts for each asset category, plus a premium for active asset management expected over the long term. U.K. Plan The overall expected long-term return on plan assets is a weighted-average of the expected long-term returns for equity securities, debt securities and other assets. The redemption yield at the measurement date on U.K. government fixed interest bonds and the yield on corporate bonds are used as proxies for the return on the debt portfolio. The returns for equities and property are estimated as a premium of 3.0 percent added to the risk-free rate. Cash is assumed to have a long-term return of 5.25 percent. Other Defined Benefit Plans The Company maintains funded and unfunded defined benefit plans in other foreign locations. The liabilities and expenses associated with these plans, individually and collectively, are not material to the Company’s consolidated financial statements. Discount rates for these plans are determined based on local interest rates and plan participant data. Cash Flows As a result of pension funding relief included in the Highway and Transportation Funding Act of 2014, the Company does no t expect to make any 2024 contributions to the funded U.S. qualified defined benefit plans. The Company expects to contribute $ 308,000 in 2024 to the unfunded non-qualified U.S. pension plans. The Company does not expect to make any 2024 contributions to the U.K. defined benefit plan in 2024. Defined Contribution Plans The Company sponsors retirement savings defined contribution retirement plans that cover eligible U.S. and U.K. employees. The Company’s U.S. retirement plans include two qualified plans, one of which is a 401(k) plan and one of which is an employee stock ownership plan (ESOP), and one non-qualified supplemental executive plan. Prior to 2018, the Company made profit sharing contributions into the qualified retirement plans for its U.S. employees and starting in 2018 made profit sharing contributions into the qualified retirement plans for U.S. employees and for certain non-U.S. employees. Profit sharing contributions were determined using a formula applied to Company earnings. In 2021, 2022 and 2023, profit sharing contributions for U.S. employees were made to the ESOP trust. Profit sharing contributions are allocated to participant accounts on the basis of participant base earnings. Defined contribution expenses for the Company’s qualified defined contribution plans and statutory profit sharing contributions were as follows: (In thousands) 2023 2022 2021 Retirement contributions $ 8,930 $ 8,556 $ 8,134 Profit sharing contributions 2,019 5,276 5,081 Total $ 10,949 $ 13,832 $ 13,215 The Company has a rabbi trust to fund the obligations of its non-qualified supplemental executive defined contribution plans (supplemental plans). The trust comprises various mutual fund investments selected by the participants of the supplemental plans. In accordance with the accounting guidance for rabbi trust arrangements, the assets of the trust and the obligations of the supplemental plans are reported on the Company’s consolidated balance sheet. The Company elected the fair value option for the mutual fund investment assets so that offsetting changes in the mutual fund values and defined contribution plan obligations would be recorded in earnings in the same period. Therefore, the mutual funds are reported at fair value with any subsequent changes in fair value recorded in the income statement. The supplemental plan liabilities increase (i.e., supplemental plan expense is recognized) when the value of the trust assets appreciate and decrease (i.e., supplemental plan income is recognized) when the value of the trust assets decline. At December 31, 2023 , the trust asset balances and the supplemental plan liability balances were $ 450,000 . At December 31, 2022, the trust asset balances were $ 376,000 , and the supplemental plan liability balances were $ 446,000 , respectively. The differences between the trust asset balances and the supplemental liability balances were due to estimated liabilities that were not funded until after the end of the year when the actual liabilities were determined. Certain foreign locations are required by law to make profit sharing contributions to employees based on statutory formulas. For the years ended December 31, 2023, 2022 and 2021 , the Company recognized $ 480,000 , $ 421,000 and $ 219,000 , respectively, of statutory profit sharing expense that is included in the table above. In all Company locations, approximately 85 percent of union and non-union employees are eligible for either the Company’s sponsored or statutory profit sharing contributions and 100 percent of U.S. based union and non-union employees are eligible for the Company’s sponsored profit sharing contribution.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued Liabilities	14. Accrued Liabilities The composition of accrued liabilities was as follows: December 31 (In thousands) 2023 2022 Accrued payroll and benefits $ 48,459 $ 73,713 Accrued customer rebates 21,024 24,715 Other accrued liabilities 52,458 64,384 Total accrued liabilities $ 121,941 $ 162,812 The decrease in accrued payroll and benefits was mainly due to lower incentive-based compensation expense accruals.

Other Non-Current Liabilities

Other Non-Current Liabilities	12 Months Ended
	Dec. 31, 2023
Other Liabilities Disclosure [Abstract]
Other Non-Current Liabilities	15. Other Non-Current Liabilities The composition of other non-current liabilities was as follows: December 31 (In thousands) 2023 2022 Deferred revenue $ 6,647 $ 8,762 Environmental and legal matters 8,491 16,276 Deferred compensation liability 27,607 32,459 Pension liability 5,430 5,241 Other non-current liabilities 21,172 17,953 Total other non-current liabilities $ 69,347 $ 80,691

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Contingencies	16. Contingencies There are a variety of legal proceedings pending or threatened against the Company that occur in the normal course of the Company’s business, the majority of which relate to environmental assessment, protection and remediation matters. Some of these proceedings may result in fines, penalties, judgments or costs being assessed against the Company at some future time. The Company’s operations are subject to extensive local, state and federal regulations, including the U.S. Comprehensive Environmental Response, Compensation and Liability Act of 1980 (CERCLA) and the Superfund amendments of 1986 (Superfund) as well as comparable regulations applicable to the Company’s foreign locations. Over the years, the Company has received requests for information related to or has been named by government authorities as a potentially responsible party at a number of sites where cleanup costs have been or may be incurred by the Company under CERCLA and similar state statutes. In addition, the Company is from time to time involved in routine legal proceedings incidental to the conduct of its business, including personal injury, property damage, tax, trade and labor matters. The Company believes that it has made adequate provisions for the costs it is likely to incur with respect to these claims. In determining the appropriate level of environmental reserves, the Company considers several factors such as information obtained from investigatory studies; changes in the scope of remediation; the interpretation, application and enforcement of laws and regulations; changes in the costs of remediation programs; the development of alternative cleanup technologies and methods; and the relative level of the Company’s involvement at various sites for which the Company is allegedly associated. The level of annual expenditures for remedial, monitoring and investigatory activities will change in the future as major components of planned remediation activities are completed and the scope, timing and costs of existing activities are changed. As of December 31, 2023 , the Company estimated a range of possible environmental losses and legal losses of $ 20,646,000 to $ 49,351,000 . Within the range of possible environmental losses and legal losses, management has currently concluded that no single amount is more likely to occur than any other amounts in the range and, thus, has accrued at the lower end of the range. These accruals totaled $ 20,646,000 at December 31, 2023 and $ 32,628,000 at December 31, 2022. Although the Company believes that its estimated range of possible environmental losses and legal losses and its reserves are adequate for contingencies, it is possible due to the uncertainties noted above, that additional reserves could be required in the future. During 2023 , cash expenditures related to environmental remediation and certain other legal matters approximated $ 13,224,000 compared to $ 2,330,000 expensed in 2022. The majority of the increase in cash expenditures relates to remediation costs at the Company’s Maywood, New Jersey site. For certain sites, the Company has responded to information requests made by federal, state or local government agencies but has received no response confirming or denying the Company’s stated positions. As such, estimates of the total costs, or range of possible costs, of remediation, if any, or the Company’s share of such costs, if any, cannot be determined with respect to these sites. Consequently, the Company is unable to predict the effect thereof on the Company’s financial position, cash flows and results of operations. Based on the Company’s present knowledge with respect to its involvement at these sites, the possibility of other viable entities’ responsibilities for cleanup, and the extended period over which any costs would be incurred, management believes that the Company has no material liability at these sites and that these matters, individually and in the aggregate, will not have a material effect on the Company’s financial position. However, in the event of one or more adverse determinations with respect to such sites in any annual or interim period, the effect on the Company’s cash flows and results of operations for those periods could be material. Following are summaries of the Company’s major contingencies at December 31, 2023: Maywood, New Jersey Site The Company’s property in Maywood, New Jersey, property formerly owned by the Company adjacent to its current site and other nearby properties (collectively, the Maywood site) were listed on the National Priorities List in September 1993 pursuant to the provisions of CERCLA because of alleged chemical and radiological contamination. Pursuant to (i) a September 21, 1987 Administrative Order on Consent entered into between the USEPA and the Company for property formerly owned by the Company at the Maywood site and (ii) the issuance of an order on May 2, 1991 by the USEPA to the Company for property currently owned by the Company at the Maywood site, the Company has completed various Remedial Investigation/Feasibility Studies of soil and groundwater at the Maywood site. On September 24, 2014, the USEPA issued its Record of Decision (ROD) for chemically-contaminated soil at the Maywood site; the Record of Decision was amended pursuant to an Explanation of Significant Differences in January 2021. The USEPA has not yet issued a ROD for chemically-contaminated groundwater at the Maywood site. Based on the most current information available, the Company believes its recorded liability is reasonable having considered the range of estimated costs of remediation for the Maywood site. The estimate of the cost of remediation for the Maywood site could change again as the Company continues to hold discussions with the USEPA, as the design of the remedial action is finalized, if a groundwater ROD is issued or if other potentially responsible parties are identified. The ultimate amount for which the Company is liable could differ materially from the Company’s current recorded liability. D’Imperio Property Site During the mid-1970’s, Jerome Lightman and the Lightman Drum Company disposed of hazardous substances generated by the Company at several sites in New Jersey, including the D’Imperio site. The Company was named as a potentially responsible party in an October 2, 1998 lawsuit in the U.S. District Court for the District of New Jersey that involved the D’Imperio Site. The Company is cooperating with other potentially responsible parties to implement the selected remedy. Based on current information, the Company believes that its recorded liability is reasonable having considered the range of estimated cost of remediation for the D’Imperio site. Depending on the ultimate cost of the remediation at this site, the amount for which the Company is liable could differ materially from the Company’s current recorded liability. Wilmington Site Property formerly owned and operated by the Company in Wilmington, Massachusetts was listed on the National Priorities List in 2006. The Company, together with the current site owner and another potentially responsible party, entered into an Administrative Order on Consent in July 2007 to undertake a Remedial Investigation and Feasibility Study. A Record of Decision was issued by the USEPA on March 30, 2021. The Company and three other potentially responsible parties have entered into a consent decree, dated September 28, 2023, with USEPA and the Commonwealth of Massachusetts that requires the remedial design and remedial action of the remedy selected in the Record of Decision for two operable units and an interim remedy for another operable unit. Remediation at this site is being managed by its current owner, to whom the Company sold the property in 1980. The Company is contractually obligated to contribute up to five percent of the environmental response costs incurred by the current owner, with no limitation on the ultimate amount of contributions. The Company has paid the current owner $ 3,648,000 for the Company’s portion of environmental response costs at the Wilmington site through December 31, 2023. The Company has recorded a liability for its portion of the estimated remediation costs for the site. Depending on the ultimate cost of the remediation at this site, the amount for which the Company is liable could differ materially from the current recorded liability. On July 29, 2022, the Company and other potentially responsible parties were notified of a possible joint claim by federal and state trustees for alleged natural resource damages related to the Wilmington site. The alleged damages may result in a range of possible penalties and the Company believes it is probable that it will have exposure for this claim; however, at this stage, the Company is unable to predict the ultimate outcome of this claim, the allocation of costs among the potentially responsible parties or what impact, if any, the outcome might have on the Company’s financial position, results of operations or cash flows. Other U.S. Sites Through the regular environmental monitoring of its plant production sites, the Company discovered levels of chemical contamination that were above thresholds allowed by law at its Elwood, Illinois (Millsdale) and Fieldsboro, New Jersey plants. The Company voluntarily reported its results to the applicable state environmental agencies. As a result, the Company is required to perform self-remediation of the affected areas. Based on current information, the Company believes that its recorded liability for the remediation of the affected areas is appropriate based on an estimate of expected costs. However, actual costs could differ materially from the current recorded liability.

Segment Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Segment Reporting	17. Segment Reporting The Company has three reportable segments: Surfactants, Polymers and Specialty Products. Each segment provides distinct products and requires separate management due to unique markets, technologies and production processes. Surfactants are used in a variety of consumer and industrial cleaning and disinfection products as well as in agricultural products, lubricating ingredients, oil field chemicals and other specialized applications. Polymers are used primarily in the manufacture of rigid foam for thermal insulation in the construction industry, plastics, building materials, refrigeration systems and CASE applications. Specialty Products are used in food, flavoring, nutritional supplement and pharmaceutical applications. The Company evaluates the performance of its segments and allocates resources based on operating income before interest expense, other income/expense items and income tax provision. The accounting policies of the reportable segments are the same as those described in the summary of significant accounting policies. The following is segment data for the three years ended December 31, 2023, 2022 and 2021: (In thousands) Surfactants Polymers Specialty Segment 2023 Net sales $ 1,602,819 $ 642,471 $ 80,478 $ 2,325,768 Operating income 72,399 60,770 11,476 144,645 Assets 1,586,148 537,193 70,508 2,193,849 Capital expenditures 231,341 19,971 9,310 260,622 Depreciation and amortization expenses 64,377 32,426 5,789 102,592 2022 Net sales $ 1,882,745 $ 789,080 $ 101,445 $ 2,773,270 Operating income 162,746 82,897 29,895 275,538 Assets 1,579,242 565,726 96,193 2,241,161 Capital expenditures 259,442 35,679 4,926 300,047 Depreciation and amortization expenses 55,262 31,399 5,807 92,468 2021 Net sales $ 1,562,795 $ 713,440 $ 69,731 $ 2,345,966 Operating income 165,999 73,591 14,178 253,768 Assets 1,245,207 556,799 78,100 1,880,106 Capital expenditures 154,953 29,077 4,976 189,006 Depreciation and amortization expenses 51,375 30,598 5,836 87,809 Below are reconciliations of segment data to the consolidated financial statements: (In thousands) 2023 2022 2021 Operating income - segment totals $ 144,645 $ 275,538 $ 253,768 Goodwill and other intangibles impairment (3)(4) ( 2,038 ) — — Business restructuring, assets impairment and loss on asset (1) ( 11,968 ) ( 308 ) ( 3,353 ) Unallocated corporate expenses (2) ( 72,026 ) ( 67,894 ) ( 79,634 ) Total operating income 58,613 207,336 170,781 Interest expense, net ( 12,103 ) ( 9,809 ) ( 5,753 ) Other, net 1,881 ( 8,824 ) 7,509 Consolidated income before income taxes $ 48,391 $ 188,703 $ 172,537 Assets - segment totals $ 2,193,849 $ 2,241,161 $ 1,880,106 Unallocated corporate assets 169,505 192,011 185,506 Consolidated assets $ 2,363,354 $ 2,433,172 $ 2,065,612 Capital expenditures - segment totals $ 260,622 $ 300,047 $ 189,006 Unallocated corporate expenditures ( 287 ) 1,506 5,476 Consolidated capital expenditures $ 260,335 $ 301,553 $ 194,482 Depreciation and amortization expenses – segment totals $ 102,592 $ 92,468 $ 87,809 Unallocated corporate depreciation expenses 2,746 2,182 3,067 Consolidated depreciation and amortization expenses $ 105,338 $ 94,650 $ 90,876 (1) See Note 22, Business Restructuring, Assets Impairment and Asset Disposition , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) regarding business restructuring and asset disposition costs. (2) Unallocated corporate expenses are primarily comprised of corporate administrative expenses (e.g., corporate finance, legal, human resources, information technology, deferred compensation and environmental remediation) that are not included in segment operating income and not used to evaluate segment performance. (3) See Note 4, Goodwill and Other Intangibles Assets , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) regarding goodwill and other intangibles impairment. (4) 2023 Goodwill and other intangibles impairment expenses and 2023, 2022 and 2021 business restructuring, assets impairment and loss on asset disposition expenses were excluded from segment results. Below is certain Company-wide geographic data for the years ended December 31, 2023, 2022 and 2021: (In thousands) 2023 2022 2021 Net sales (1) United States $ 1,312,866 $ 1,579,194 $ 1,297,650 France 202,038 227,421 179,746 Poland 171,889 195,781 198,883 United Kingdom 174,574 229,836 208,780 Brazil 124,661 175,004 136,799 Mexico 144,163 148,858 127,944 All other countries 195,577 217,176 196,164 Total $ 2,325,768 $ 2,773,270 $ 2,345,966 Long-lived assets (2) United States $ 1,007,337 $ 896,867 $ 668,362 Netherlands 80,335 79,007 85,931 Germany 41,878 42,512 41,438 Singapore 17,617 20,899 23,507 Brazil 39,512 38,493 35,294 China 25,704 28,717 30,991 United Kingdom 33,857 33,389 38,634 Mexico 73,449 52,917 45,384 All other countries 36,989 34,444 39,034 Total $ 1,356,678 $ 1,227,245 $ 1,008,575 (1) Net sales are attributed to countries based on the location of the Company legal entity making the sale. (2) Includes net property, plant and equipment, goodwill and other intangible assets.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Earnings Per Share	18. Earnings Per Share Below is the computation of basic and diluted earnings per share for the years ended December 31, 2023, 2022 and 2021: (In thousands, except per share amounts) 2023 2022 2021 Computation of Basic Earnings per Share Net income attributable to Stepan Company $ 40,204 $ 147,153 $ 137,804 Weighted-average number of shares outstanding 22,777 22,781 22,922 Basic earnings per share $ 1.77 $ 6.46 $ 6.01 Computation of Diluted Earnings per Share Net income attributable to Stepan Company $ 40,204 $ 147,153 $ 137,804 Weighted-average number of shares outstanding 22,777 22,781 22,922 Add weighted-average net shares from assumed (1) 66 104 138 Add weighted-average net shares related to unvested 3 1 1 Add weighted-average net shares from assumed 67 111 166 Add weighted-average contingently issuable net shares 33 67 60 Weighted-average shares applicable to diluted 22,946 23,064 23,287 Diluted earnings per share $ 1.75 $ 6.38 $ 5.92 (1) Options/SARs to purchase 672,485 , 343,715 and 103,182 shares of the Company’s common stock were excluded from the computations of diluted earnings per share for the years ended December 31, 2023, 2022 and 2021 , respectively. The options’/SARs’ exercise prices were greater than the average market price for the Company’s common stock and inclusion of the instruments would have had an antidilutive effect on the computations of earnings per share.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	19. Accumulated Other Comprehensive Income (Loss) Below is the change in the Company’s accumulated other comprehensive income (loss) (AOCI) balance by component (net of income taxes) for the years ended December 31, 2023, 2022 and 2021: (In thousands) Foreign Defined Cash Flow Total Balance at December 31, 2020 $ ( 107,083 ) $ ( 29,861 ) $ 63 $ ( 136,881 ) Other comprehensive income before reclassifications ( 28,185 ) 8,188 — ( 19,997 ) Amounts reclassified from AOCI — 3,651 ( 9 ) 3,642 Net current period other comprehensive income ( 28,185 ) 11,839 ( 9 ) ( 16,355 ) Balance at December 31, 2021 $ ( 135,268 ) $ ( 18,022 ) $ 54 $ ( 153,236 ) Other comprehensive income before reclassifications ( 21,567 ) ( 2,857 ) 8,357 ( 16,067 ) Amounts reclassified from AOCI — 1,800 ( 9 ) 1,791 Net current period other comprehensive income ( 21,567 ) ( 1,057 ) 8,348 ( 14,276 ) Balance at December 31, 2022 $ ( 156,835 ) $ ( 19,079 ) $ 8,402 $ ( 167,512 ) Other comprehensive income before reclassifications 40,423 ( 1,630 ) ( 2,174 ) 36,619 Amounts reclassified from AOCI — 301 ( 10 ) 291 Net current period other comprehensive income 40,423 ( 1,329 ) ( 2,184 ) 36,910 Balance at December 31, 2023 $ ( 116,412 ) $ ( 20,408 ) $ 6,218 $ ( 130,602 ) Amounts reclassified out of AOCI for the three years ended December 31, 2023, 2022 and 2021, is displayed below: Amounts Reclassified from AOCI (1) (In thousands) 2023 2022 2021 Affected Line Item in Amortization of defined pension items: Prior service cost $ ( 10 ) $ ( 9 ) $ ( 12 ) Actuarial loss ( 392 ) ( 2,393 ) ( 4,800 ) $ ( 402 ) ( 2,402 ) ( 4,812 ) Total before tax (2) 101 602 1,161 Tax benefit $ ( 301 ) $ ( 1,800 ) $ ( 3,651 ) Net of tax Gains and losses on cash flow hedges: Foreign exchange contracts $ 10 $ 9 $ 9 Cost of sales 10 9 9 Total before tax — — — Tax benefit $ 10 $ 9 $ 9 Net of tax Total reclassifications for the period $ ( 291 ) $ ( 1,791 ) $ ( 3,642 ) Net of tax (1) Amounts in parentheses denote expense to the Company’s Consolidated Statements of Income. (2) This component of accumulated other comprehensive income is included in the computation of net periodic benefit cost (see Note 13, Postretirement Benefit Plans , of the notes to the Company’s consolidated financial statements for details regarding net periodic benefit costs for the Company’s U.S. and U.K. defined benefit plans).

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2023
Business Combinations [Abstract]
Acquisitions	20. Acquisitions 2022 Acquisition PerformanX Acquisition On September 23, 2022 , the Company completed the acquisition of the surfactants business and associated assets of PerformanX Specialty Chemicals, LLC. This acquisition enhanced the Company’s specialty alkoxylates portfolio and provides market diversification opportunities. This acquisition is also expected to deliver additional baseload volumes for the Company’s Pasadena, Texas alkoxylation facility that is expected to start up in the first half of 2024. The purchase price of the acquisition was $ 9,693,000 and was paid for with cash on hand. This acquisition was accounted for as a business combination and the assets were measured and recorded at their estimated fair values. The primary assets acquired were intangibles, mostly comprised of goodwill ($ 1,792,000 ), manufacturing know-how ($ 2,750,000 ), customer relationships ($ 3,250,000 ) and non-compete agreements ($ 10,000 ). The Company also acquired inventory ($ 1,312,000 ) and working capital ($ 579,000 ). All of the acquired assets are included within the Company’s Surfactants segment. The Company finalized the purchase price allocation during the fourth quarter of 2022. The average amortization period for the acquired identifiable intangibles assets has been estimated to be in the range of nine to ten years for manufacturing know-how and nine to 11 year s for customer relationships. 2021 Acquisitions Acquisition of INVISTA’s Aromatic Polyester Polyol Business On January 29, 2021 , the Company and its wholly-owned subsidiaries Stepan Holdings Netherlands B.V. and Stepan UK Limited (collectively, “Stepan”) entered into a Stock and Asset Purchase Agreement with Arteva Specialties B.V., INV Performance Surfaces, LLC, INVISTA Textiles (U.K.) Limited, INV Management Services, LLC, and INVISTA Equities, LLC (collectively, “INVISTA”) to acquire INVISTA’s aromatic polyester polyol business and associated assets. Included in the transaction were two manufacturing sites, one in Wilmington, North Carolina (U.S.) and the other in Vlissingen, Netherlands, along with intellectual property, customer relationships, inventory and working capital. The purchase price was $ 165,000,000 , plus $ 21,560,000 of working capital and $ 3,000,000 of associated value-added taxes (VAT), and was paid for with cash on hand. The working capital acquired included $ 5,900,000 of cash. The Company finalized the purchase price allocation during the third quarter of 2021. The following table summarizes the purchase price allocation for the major components of the acquisition: (In thousands) Assets: Property, plant and equipment $ 54,200 Identifiable intangibles assets 46,000 Goodwill 64,800 Total assets acquired $ 165,000 Fermentation Plant Acquisition On February 2, 2021, the Company completed the acquisition of a fermentation plant located in Lake Providence, Louisiana. The Company believes this plant complements the rhamnolipid-based bio-surfactant technology the Company acquired from Logos Technologies in March 2020. Fermentation is a new platform technology for the Company and the Company is focusing efforts to further develop, integrate, produce and commercialize these unique surfactants moving forward. Bio-surfactants, produced via fermentation, are attractive due to their biodegradability, low toxicity, and in some cases, unique antimicrobial properties. These bio-surfactants offer potential synergies in several strategic end use markets including oilfield, agriculture, personal care and household, industrial and institutional cleaning. The acquisition of this industrial scale fermentation plant represents a step in the Company’s bio-surfactant commercialization efforts. The purchase price was $ 3,500,000 and was paid for with cash on hand. This acquisition has been accounted for as an asset acquisition.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	21. Revenue from Contracts with Customers The Company deems a contract with a customer to exist when a purchase order is received from a customer for a specified quantity of product or products and the Company acknowledges receipt of such purchase order. In some instances, the Company has entered into manufacturing supply agreements with customers but these agreements typically do not bind a customer to any purchase volume requirements and thus an obligation is not created until the customer submits a purchase order to the Company. The Company’s contracts typically have a single performance obligation that is satisfied at the time product is shipped and control passes to the customer. For a small portion of the business, performance obligations are deemed satisfied when product is delivered to a customer location. As of December 31, 2023 , the Company had $ 688,000 of contract liabilities and no contract assets. A contract liability would typically arise when an advance or deposit is received from a customer before the Company recognizes revenue. In practice, this is rare as it would require a customer to make a payment prior to a performance obligation being satisfied. When such situations do arise, the Company maintains a deferred revenue liability until the time a performance obligation has been satisfied. The Company recognized $ 739,000 of revenue in 2023 from pre-existing contract liabilities at December 31, 2022. During 2020 the Company recorded $ 10,709,000 of long-term deferred revenue associated with a payment received to defray the cost of capital expenditures necessary to service a customer’s future product needs. On December 31, 2023 , $ 6,647,000 was classified as long-term and $ 2,216,000 was classified as short-term. This deferred revenue will be recognized over the period of the contract and $ 1,846,000 of revenue has been recognized from this contract as of December 31, 2023. The tables below provide a geographic disaggregation of net sales for the years ended December 31, 2023, 2022 and 2021. The Company’s business segmentation by geographic region most effectively captures the nature and economic characteristics of the Company’s revenue streams impacted by economic factors. 2023 (In thousands) Surfactants Polymers Specialty Total Geographic Market North America $ 949,218 $ 338,979 $ 66,802 $ 1,354,999 Europe 289,010 259,491 13,414 561,915 Latin America 304,870 1,112 262 306,244 Asia 59,721 42,889 — 102,610 Total $ 1,602,819 $ 642,471 $ 80,478 $ 2,325,768 2022 (In thousands) Surfactants Polymers Specialty Total Geographic Market North America $ 1,099,616 $ 437,312 $ 83,807 1,620,735 Europe 349,651 307,441 16,118 673,210 Latin America 363,799 4,629 1,520 369,948 Asia 69,679 39,698 — 109,377 Total $ 1,882,745 $ 789,080 $ 101,445 $ 2,773,270 2021 (In thousands) Surfactants Polymers Specialty Total Geographic Market North America $ 904,469 $ 364,382 $ 59,461 1,328,312 Europe 288,735 302,137 9,152 600,024 Latin America 299,601 3,823 1,118 304,542 Asia 69,990 43,098 — 113,088 Total $ 1,562,795 $ 713,440 $ 69,731 $ 2,345,966

Business Restructuring, Assets

Business Restructuring, Assets Impairment and Asset Disposition	12 Months Ended
	Dec. 31, 2023
Restructuring and Related Activities [Abstract]
Business Restructuring, Assets Impairment and Asset Disposition	22. Business Restructuring, Assets Impairment and Asset Disposition 2023 Restructuring During the third quarter of 2023 the Company recorded a $ 5,530,000 restructuring reserve associated with a voluntary early retirement program. This program was offered to eligible employees at the Company’ s corporate headquarters and global technology center to reduce costs. During the fourth quarter of 2024, the Company recognized an additional $ 2,883,000 of restructuring expense associated with workforce productivity measures to reduce costs. In addition, the Company also recognized $ 3,164,000 of asset impairment charges in the fourth quarter of 2023. These asset impairment charges primarily relate to assets that are no longer in use and to the write-off of engineering and design costs associated with projects the Company no longer deems viable. All of the restructuring charges described above were excluded from Segment operating results and are recorded on the Business restructuring, assets impairment and loss on asset disposition line item of the Consolidated Statements of Income for the year ended December 31, 2023. See Note 17, Segment Reporting, of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for additional details. 2016 Restructuring During 2016, the Company shut down its Longford Mills, Ontario, Canada (Longford Mills) manufacturing facility, a part of the Surfactant reportable segment. The shutdown plan was implemented to improve the Company’s asset utilization in North America and to reduce the Company’s fixed cost base. Manufacturing operations of the Longford Mills plant ceased by the end of 2016, and production of goods manufactured at the facility was transferred to other Company North American production sites. As of December 31, 2023 , $ 9,949,000 of aggregate restructuring expense had been recognized, reflecting $ 1,644,000 of termination benefits for approximately 30 employees and $ 8,305,000 for other expenses, principally site decommissioning costs. The Company recognized restructuring expenses of $ 391,000 , $ 308,000 and $ 633,000 in 2023, 2022 and 2021, respectively. Asset Disposition In the fourth quarter of 2021, the Company sold one of its corporate headquarters buildings and recognized a $ 2,720,000 loss on the sale of the building. The loss is reflected in the Business restructuring, assets impairment and loss on asset disposition line on the Company’s consolidated statements of income.

Noncash Investing and Financing

Noncash Investing and Financing Activities	12 Months Ended
	Dec. 31, 2023
Supplemental Cash Flow Elements [Abstract]
Noncash Investing and Financing Activities	23. Noncash Investing and Financing Activities Noncash investing activities included liabilities (accounts payable) incurred for property, plant and equipment expenditures of approximately $ 16,222,000 , $ 55,480,000 , and $ 36,588,000 that were unpaid at December 31, 2023, 2022 and 2021 , respectively. Noncash financing activities included 103,745 shares of the Company’s common stock (valued at $ 10,916,000 ), 58,441 shares of the Company’s common stock (valued at $ 6,095,000 ) and 60,132 shares of the Company’s common stock (valued at $ 7,286,000 ) issued in connection with the Company’s equity incentive compensation plan in 2023, 2022 and 2021 , respectively.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations Stepan Company’s (the Company) operations consist predominantly of the production and sale of specialty and intermediate chemicals, which are sold to other manufacturers for use in a variety of end products. Principal markets for all products are manufacturers of cleaning and washing compounds (including detergents, shampoos, fabric softeners, toothpastes and household cleaners), paints, cosmetics, food, beverages, nutritional supplements, agricultural products, plastics, furniture, automotive equipment, insulation and refrigeration.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (GAAP) requires Company management to make estimates and assumptions that affect the reported amounts of assets, liabilities, income and expenses at the date of the financial statements and to provide disclosures of contingent assets, liabilities and related amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and all wholly-owned subsidiaries in which the Company exercises controlling influence. The equity method is used to account for investments in which the Company exercises significant but noncontrolling influence. Intercompany balances and transactions are eliminated in consolidation. Prior to the fourth quarter of 2021, the Company had an 80 percent ownership interest in the Nanjing Stepan Jinling Chemical Limited Liability Company (a joint venture) and exercised controlling influence over the entity. As a result, the China joint venture results were included in the Company’s consolidated financial statements. The partner’s interest in the joint venture’s net income was reported in the net income attributable to noncontrolling interest line of the consolidated statements of income and its interest in the net assets of the joint venture was reported in the noncontrolling interest line (a component of equity separate from Company equity) of the consolidated balance sheets. The joint venture was dissolved during the fourth quarter of 2021.
Business Combinations	Business Combinations The Company makes acquisitions from time to time. When such acquisitions occur, the Company applies the accounting guidance per FASB ASC Topic 805, Business Combinations (ASC 805), to determine whether the acquisition should be treated as an asset acquisition or a business combination. When the acquisition meets the criteria of a business combination the Company recognizes the identifiable assets acquired and liabilities assumed at their estimated fair values as of the date of the acquisition. The Company recognizes goodwill for any portion of the purchase price that exceeds the sum of the net fair value of all the assets purchased in the acquisition and the liabilities assumed. Considerable estimates, complex judgments and assumptions are typically required to arrive at the fair value of elements acquired in a business combination, inclusive of discount rates, customer attrition rates, royalty rates, economic lives, and estimated future cash flows expected to be generated from the assets acquired. These items are typically most relevant to the fair valuation of identifiable intangible assets and property, plant and equipment. In some instances, the purchase price allocation of an acquisition is not complete by the end of a reporting period. This situation most typically arises when an acquisition is complex and/or completed very close to the end of a reporting period and all necessary information is not available by the end of the reporting period in which the acquisition occurs. In these instances, the Company reports provisional amounts for any incomplete items and makes subsequent adjustments as necessary information becomes available or determines that additional information is not obtainable. Any subsequent adjustments could have a material impact on the Company’s financial position or results of operations as they could impact the initial fair values assigned to intangible assets and property, plant and equipment and/or their estimated economic lives. ASC 805 requires purchase price allocations to be finalized within one year from the acquisition date.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid investments with purchased maturities of three months or less to be cash equivalents. At December 31, 2023 , the Company’s cash and cash equivalents totaled $ 129,823,000 including $ 15,117,000 in money market funds each rated AAAm by Standard and Poor’s, Aaa-mf by Moody’s and AAAmmf by Fitch. Cash in U.S. demand deposit accounts totaled $ 6,374,000 , and cash of the Company’s non-U.S. subsidiaries held outside the U.S. totaled $ 108,332,000 as of December 31, 2023. At December 31, 2022 , the Company’s cash and cash equivalents totaled $ 173,750,000 including $ 64,851,000 in money market funds, each of which was rated AAAm by Standard and Poor’s, Aaa-mf by Moody’s and AAAmmf by Fitch. Cash in U.S. demand deposit accounts totaled $ 11,811,000 and cash of the Company’s non-U.S. subsidiaries held outside the U.S. totaled $ 97,088,000 as of December 31, 2022 .
Receivables and Credit Risk/Losses	Receivables and Credit Risk/Losses Receivables are stated net of allowances for doubtful accounts and other allowances and primarily include trade receivables from customers, as well as nontrade receivables from suppliers, governmental tax agencies and others. The Company is exposed to both credit risk and losses on accounts receivable balances. The Company’s credit risk and loss exposure predominately relates to the sale of products to its customers. When extending credit to customers the Company evaluates a customer’s credit worthiness based on a combination of qualitative and quantitative factors, inclusive of, but not limited to, a customer’s credit rating from external providers, financial condition and past payment experience. The Company performs credit reviews on all customers at inception and on a scheduled basis thereafter dependent on customer risk and the level of credit extended. Payment terms extended are short term in duration, typically ranging from 30 to 60 days . The majority of the Company’s sales are made to large companies that are able to weather periodic changes in economic conditions. This risk of losses is further mitigated by the Company’s diverse customer base, which is dispersed over various geographic regions and industrial sectors. No single customer comprised more than 10 percent of the Company’s consolidated net sales in 2023, 2022 or 2021. The Company maintains allowances for potential credit losses. With the adoption of ASU No. 2016-13, Financial Instruments – Credit Losses, the Company assesses the likelihood of default based on various factors, including the length of time receivables are past due, historical experience, current economic conditions and forward-looking economic forecasts. The Company also evaluates expected losses based on portfolios of data inclusive of geographical areas, specific end market uses of its products, etc. Although the Company’s historical credit loss experience has not been significant, its exposure to credit losses may increase if customers are adversely affected by economic challenges and/or uncertainty due to domestic or global recessions, disruptions due to pandemics, or other adverse global/regional events and customer specific factors. Specific customer allowances are recorded when a review of customer creditworthiness and current economic conditions indicate that collection is doubtful. General allowances are also maintained based on historical averages and trade receivable levels and incorporate existing economic conditions and forecast assumptions, when warranted. The Company reviews its reserves for credit losses on a quarterly basis. The Company also maintains other customer allowances that occur in the normal course of business. The following is an analysis of the allowance for doubtful accounts and other accounts receivable allowances for the years ended December 31, 2023, 2022 and 2021: (In thousands) 2023 2022 2021 Balance at January 1 $ 11,100 $ 10,157 $ 10,133 Provision charged to income 765 1,374 943 Accounts written off, net of recoveries ( 722 ) ( 431 ) ( 919 ) Balance at December 31 $ 11,143 $ 11,100 $ 10,157
Inventories	Inventories Inventories are valued at cost, which is not in excess of net realizable value, and include material, labor and plant overhead costs. The first in, first out (FIFO) method is used to determine the cost of the Company’s inventory.
Property, Plant and Equipment	Property, Plant and Equipment Depreciation of property, plant and equipment is provided on a straight-line basis over the estimated useful lives of the assets. Lives used for calculating depreciation are generally 30 years for buildings and 15 years for building improvements. For assets classified as machinery and equipment, lives generally used for calculating depreciation expense range from 10 to 15 years for manufacturing equipment, five to 10 years for furniture and fixtures, three to five years for vehicles and three to 10 years for computer equipment and software. The manufacturing of chemicals is capital intensive and a large majority of the assets included within machinery and equipment represent manufacturing equipment. Major renewals and betterments are capitalized in the property accounts, while maintenance and repairs ($ 80,226,000 , $ 82,110,000 , and $ 75,351,000 in 2023, 2022 and 2021, respectively), which do not renew or extend the life of the respective assets, are charged to operations as incurred. Land is not depreciated. The cost of property retired or sold, and the related accumulated depreciation, are removed from the accounts and any resulting gain or loss is reflected in income. Long-lived assets are reviewed for impairment when conditions exist that indicate the carrying amount of the assets may not be fully recoverable. Such conditions could include significant adverse changes in the business environment, significant declines in forecasted operations or an approved plan to discontinue an asset or an asset group before the end of its useful life. Included in the computer equipment and software component of machinery and equipment are costs related to the acquisition and development of internal-use software. Capitalized costs for internal-use software include external direct costs of materials and services consumed in obtaining and developing the software. For development projects where major internal resources are committed, payroll and payroll-related costs incurred during the application development phase of the project are also capitalized. The capitalized costs are amortized over the useful lives of the software, which are generally three to 10 years . Costs incurred in the preliminary project phase are expensed. Deferred implementation costs for hosted cloud computing service arrangements are stated at historical cost and amortized on a straight-line basis over the term of the hosting arrangement. Interest charges on borrowings applicable to major construction projects are capitalized.
Deferred Compensation	Deferred Compensation The Company sponsors deferred compensation plans that allow management employees to defer receipt of their annual cash incentive compensation and performance shares and non-employee directors to defer receipt of their fees and stock awards until retirement, departure from the Company or as elected by the participant. The plans allow for the deferred compensation to grow or decline based on the results of investment options chosen by the participants. The investment options include Company common stock and a limited selection of mutual funds. The Company funds the obligations associated with these plans by purchasing investment assets that match the investment choices made by the plan participants. A sufficient number of shares of treasury stock are maintained on hand to cover the equivalent number of shares that result from participants electing the Company common stock investment option. As a result, the Company must periodically purchase its common shares in the open market or in private transactions. Upon retirement or departure from the Company or at the elected time, participants receive cash amounts equivalent to the payment date value of the investment choices they have made or shares of Company common stock equal to the number of share equivalents held in the accounts. Some plan distributions may be made in cash or Company common stock at the option of the participant. Other plan distributions can only be made in Company common stock. For deferred compensation obligations that may be settled in cash, the Company must record appreciation in the market value of the investment choices made by participants as additional compensation expense. Conversely, declines in the value of Company stock or the mutual funds result in a reduction of compensation expense since such declines reduce the cash obligation of the Company as of the date of the financial statements. These market price movements may result in significant period-to-period fluctuations in the Company’s income. The increases or decreases in compensation expenses attributable to market price movements are reported in the operating expenses section of the consolidated statements of income. Because the obligations that must be settled only in Company common stock are treated as equity instruments, fluctuations in the market price of the underlying Company stock do not affect earnings. At December 31, 2023 and December 31, 2022 , the Company’s deferred compensation liability was $ 39,847,000 and $ 43,005,000 , respectively. In 2023 and 2022 , approximately 34 percent of deferred compensation liability represented deferred compensation tied to the performance of the Company’s common stock. The remainder of the deferred compensation liability was tied to the chosen mutual fund investment assets. A $ 1.00 increase in the market price of the Company’s common stock will result in approximately $ 143,000 of additional compensation expense. A $ 1.00 reduction in the market price of the common stock will reduce compensation expense by a like amount. The expense or income associated with the mutual fund component will generally fluctuate in line with the overall percentage increase or decrease of the U.S. stock markets. The mutual fund assets related to the deferred compensation plans are recorded on the Company’s balance sheet at cost when acquired and adjusted to their market values at the end of each reporting period. As allowed by generally accepted accounting principles, the Company elected the fair value option for recording the mutual fund investment assets. Therefore, market value changes for the mutual fund investment assets are recorded in the income statement in the same periods that the offsetting changes in the deferred compensation liabilities are recorded. Dividends, capital gains distributed by the mutual funds and realized and unrealized gains and losses related to mutual fund shares are recognized as investment income or loss in the other, net line of the consolidated statements of income.
Fair Value Measurements	Fair Value Measurements GAAP defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Furthermore, GAAP establishes a framework, in the form of a three-level hierarchy, for measuring fair value that prioritizes the inputs to valuation techniques used to measure fair value. The following describes the hierarchy levels: Level 1 - quoted prices in active markets for identical assets and liabilities. Level 2 - inputs other than quoted prices included within Level 1 that are directly or indirectly observable for the asset or liability, such as quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets and liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data. Level 3 - unobservable inputs which reflect the entity’s own assumptions about the assumptions market participants use in pricing the assets and liabilities. The Company applies the fair value measurement provisions of GAAP to any of its financial assets and liabilities that are carried at fair value on the consolidated balance sheets (see Note 2, Fair Value Measurements , of the notes to the Company’s consolidated financial statements included in Item 8 of this Form 10-K), its outstanding debt for disclosure purposes (see Note 2, Fair Value Measurements , of the notes to the Company’s consolidated financial statements included in Item 8 of this Form 10-K) and its pension plan assets (see Note 13, Postretirement Benefit Plans , of the notes to the Company’s consolidated financial statements included in Item 8 of this Form 10-K). The Company also applies fair value measurements to nonfinancial assets and liabilities recorded in conjunction with business combinations and as part of impairment reviews for goodwill and other long-lived assets.
Revenue Recognition	Revenue Recognition The Company’s contracts typically have a single performance obligation that is satisfied at the time product is shipped and control passes to the customer. For a small portion of the business, performance obligations are deemed satisfied when product is delivered to a customer location. For arrangements where the Company consigns product to a customer location, revenue is recognized when the customer uses the inventory. The Company accounts for shipping and handling as activities to fulfill a promise to transfer a good. As such, shipping and handling fees billed to customers in a sales transaction are recorded in Net Sales and shipping and handling costs incurred are recorded in Cost of Sales. Volume and cash discounts due customers are estimated and recorded in the same period as the sales to which the discounts relate and are reported as reductions of revenue in the consolidated statements of income. See Note 21, Revenue from Contracts with Customers , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for more details.
Cost of Sales	Cost of Sales Cost of sales is comprised of raw material costs (including inbound freight expense to deliver the raw materials), manufacturing plant labor expenses and various manufacturing overhead expenses, such as utilities, maintenance, operating supplies, amortization and manufacturing asset depreciation expenses. Cost of sales also includes outbound shipping and handling expenses, inter-plant transfer costs, warehouse expenses and rail car rental expenses.
Operating Expenses	Operating Expenses Selling expenses are comprised of salaries and related fringe benefit expenses for marketing and sales personnel and operating costs, such as outside agent commissions, automobile rental and travel-related expenses, which support the sales and marketing functions. Bad debt charges and any depreciation expenses related to marketing assets (e.g., computers) are also classified as selling expenses. Administrative expenses are comprised of salaries and related fringe benefit expenses and operating costs for the Company’s various administrative functions, which include information technology, finance, legal, and human resources. The majority of environmental remediation expenses are also classified as administrative expense. The Company’s research and development costs are expensed as incurred. These expenses are aimed at the discovery of new knowledge with the intent that such effort will be useful in developing and commercializing a new product or in bringing about a significant improvement to an existing product or process. Total research and development expenses were $ 35,732,000 , $ 40,902,000 , and $ 38,778,000 in 2023, 2022 and 2021, respectively. The remainder of research, development and technical service expenses reflected on the consolidated statements of income relate to technical services, which include routine product testing, quality control and sales service support. Compensation expenses or income related to the Company’s deferred compensation plans is presented in the deferred compensation (income) expense line in the Consolidated Statements of Income. For more details, see Note 12, Deferred Compensation, of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K).
Environmental Expenditures	Environmental Expenditures Environmental expenditures that relate to current operations are typically recorded in cost of sales. Expenditures that mitigate or prevent environmental contamination and that benefit future operations are capitalized as assets and depreciated on a straight-line basis over the estimated useful lives of the assets, which are typically 10 years. Estimated future expenditures that relate to an existing condition caused by past operations, and which do not contribute to current or future revenue generation, are recorded as liabilities, with the corresponding charge typically recorded in administrative expenses, when environmental assessments and/or remedial efforts are probable and the cost or range of possible costs can be reasonably estimated. When no amount within the range is a better estimate than any other amount, the minimum amount in the range is accrued. Estimating the possible costs of remediation requires making assumptions related to the nature and extent of contamination and the methods and resulting costs of remediation. Some of the factors on which the Company bases its estimates include information provided by feasibility studies, potentially responsible party negotiations and the development of remedial action plans. Legal costs related to environmental matters are expensed as incurred. See Note 16, Contingencies , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for environmental contingencies details.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets The Company’s intangible assets include patents, trademarks, customer lists and relationships, technological and manufacturing know-how and goodwill, all of which were acquired as part of business or product line acquisitions. Intangible assets other than goodwill are determined to have either finite or indefinite useful lives. The Company currently has no indefinite-life intangible assets other than goodwill. The values for intangible assets with finite lives are amortized over the useful lives of the assets. Currently, the useful lives for the Company’s finite-lived intangible assets are as follows: patents – 15 years; trademarks – eight to 11 years ; customer relationships – ten to 20 years and know-how – seven to 20 years . In addition, finite-life intangible assets are tested for impairment when events or changes in circumstances indicate that the carrying value of an intangible asset may not be recoverable. Goodwill is not amortized but is tested for impairment at least annually, or more frequently, if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit to which goodwill relates below the reporting unit’s carrying value. See Note 4, Goodwill and Other Intangibles , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for detailed information about goodwill and other intangible assets.
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. Deferred tax assets are recognized to the extent that the Company believes these assets are more likely than not to be realized. In making such a determination, we consider all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If we determine that we would be able to realize our deferred tax assets in the future in excess of their net recorded amount, we would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. Uncertain tax positions are recorded in accordance with ASC 740, Income Taxes, on the basis of a two-step process whereby (1) we determine whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, we recognize the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company recognizes interest and penalties related to unrecognized tax benefits within the income tax expense line in the accompanying Consolidated Statements of Income. Accrued interest and penalties are included within the related tax liability line in the Consolidated Balance Sheet. See Note 9, Income Taxes , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for more information about the Company’s income taxes.
Translation of Foreign Currencies	Translation of Foreign Currencies For the Company’s consolidated foreign subsidiaries whose functional currency is the local foreign currency, assets and liabilities are translated into U.S. dollars at exchange rates in effect at year end and revenues and expenses are translated at average exchange rates for the year. Any resulting translation adjustments are included within the consolidated balance sheets on the accumulated other comprehensive loss line of stockholders’ equity. Gains or losses on foreign currency transactions are reflected in the other, net line of the consolidated statements of income. The Company has four foreign subsidiaries whose functional currencies are the U.S. dollar. For these subsidiaries, nonmonetary assets and liabilities are translated at historical rates, monetary assets and liabilities are translated at exchange rates in effect at year end, revenues and expenses are translated at average exchange rates for the year and translation gains and losses are included in the other, net caption of the consolidated statements of income.
Stock-Based Compensation	Stock-Based Compensation The Company grants stock options, performance shares, time-based restricted stock units (RSUs) and stock appreciation rights (SARs) to certain employees under its incentive compensation plans. The Company calculates the fair values of stock options, performance shares, RSUs and SARs on the date such instruments are granted. The fair values of the stock options, performance shares and RSUs are then recognized as compensation expense over the vesting periods of the instruments. The Company’s SARs granted prior to 2015 were cash-settled and SARs granted in 2015 and later are stock-settled. All of the cash-settled SARs were exercised prior to the end of 2023. Compensation expense for the stock-settled SARs is calculated in the same way as compensation expense for stock options. See Note 11, Stock-based Compensation , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for detailed information about the Company’s stock-based compensation.
Earnings Per Share	Earnings Per Share Basic earnings per share amounts are computed as net income attributable to the Company divided by the weighted-average number of common shares outstanding. Diluted earnings per share amounts are based on the weighted-average number of common shares outstanding plus the weighted-average of net common shares (under the treasury stock method) that would be outstanding assuming the exercise of outstanding stock options and stock-settled SARs, the vesting of unvested RSUs that have no performance or market condition and the issuance of contingent performance shares. See Note 18, Earnings Per Share , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for detailed information about the Company’s earnings per share calculations.
Comprehensive Income and Accumulated Other Comprehensive Income	Comprehensive Income and Accumulated Other Comprehensive Income Comprehensive income includes net income and all other non-owner changes in equity that are not reported in net income. Comprehensive income is disclosed in the consolidated statements of comprehensive income. Accumulated other comprehensive income (AOCI) is reported as a component of stockholders’ equity in the Company’s consolidated balance sheets. See Note 19, Accumulated Other Comprehensive Income (Loss) , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for detailed information regarding changes in the Company’s AOCI and reclassifications out of AOCI to income.
Segment Reporting	Segment Reporting The Company reports financial and descriptive information about its reportable operating segments. Operating segments are components of the Company that have separate financial information that is regularly evaluated by the chief operating decision maker to assess segment performance and allocate resources. The Company discloses segment revenue, operating income, assets, capital expenditures and depreciation and amortization expenses. Enterprise-wide financial information about the geographic locations in which the Company earns revenues and holds assets is also disclosed. See Note 17, Segment Reporting , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for detailed information about the Company’s segment reporting.
Derivative Instruments	Derivative Instruments Derivative instruments are recognized in the consolidated balance sheets as either assets or liabilities measured at fair value. For derivative instruments that are not designated as hedging instruments, changes in the fair values of the derivative instruments are recognized currently in earnings. For derivative instruments designated as hedging instruments, depending on the nature of the hedge, changes in the fair values of the derivative instruments are either offset in earnings against changes in the fair values of the hedged items or recognized in AOCI until the hedged transaction is recognized in earnings. At the time a hedging relationship is designated, the Company establishes the method it will use for assessing the effectiveness of the hedge and the measurement approach for determining the ineffective aspect of the hedge. Company policy prohibits the use of derivative instruments for trading or speculative purposes. See Note 3, Derivative Instruments , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for further information regarding the Company’s use of derivatives. At December 31, 2023 , the Company held open forward contracts for the purchase of 0.7 million dekatherms of natural gas in 2024 at a cost of $ 3,403,000 . The Company uses forward contracts to minimize its exposure to volatile natural gas prices. Because the Company anticipates taking delivery of the natural gas for use in its operations, the forward contracts qualify for the normal purchase exception provided under U.S. GAAP for derivative instruments. The Company has elected the exception for such contracts. As a result, the forward contracts are not accounted for as derivative instruments. The cost of natural gas is charged to expense at the time the natural gas is delivered and used.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848) Facilitation of the Effect of Reference Rate Reform on Financial Reporting. This update provides optional guidance for a limited period of time to ease the burden of implementing the usage of new reference rates. The amendments apply to contract modifications that replace a reference rate affected by reference rate reform and contemporaneous modifications of other contract terms related to the replacement of the reference rate. If elected, the optional expedients to contract modifications must be applied consistently for all eligible contracts or eligible transactions. The original timeframe for electing optional expedients to contract modifications was between March 12, 2020 and December 31, 2022. In December 2022, the FASB issued ASU No. 2022-06 deferring the sunset date of Topic 848 from December 31, 2022, to December 31, 2024. The guidance should be applied prospectively. Other than electing select expedients associated with an interest rate swap, the Company has not currently utilized any of the optional expedients of exceptions available under this ASU. The Company will continue to assess whether this ASU is applicable throughout the effective period. In October 2023, the FASB issued ASU No. 2023-06, Disclosure Improvements, Codification Amendments in Response to the SEC’s Disclosure Update and Simplification Initiative. The amendments in this update represent changes to clarify or improve disclosures and presentation requirements of a variety of topics, including Statement of Cash Flows-Overall (disclosures in annual periods of where cash flows associated with derivative instruments and their related gains and losses are presented), Earnings Per Share-Overall (disclosures of the methods used in the diluted earnings-per-share computation for each dilutive security), and Debt-Overall (disclosures of amounts and terms of unused lines of credit and unfunded commitments and the weighted-average interest rate on outstanding short-term borrowings). The amendments in this update are effective two years after the SEC removes currently existing disclosures from Regulation S-X or Regulation S-K. The implementation of ASU No. 2023-06 will not have an impact on the Company’s financial position, results of operations and cash flow but will impact the Company’s interim and annual disclosures related to the relevant subtopics in this update. In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280) Improvements to Reportable Segment Disclosures. This update requires more enhanced and detailed interim and annual disclosures regarding significant segment expenses and other segment items that are regularly provided to the chief operating decision maker. These items include the difference between segment revenue less the segment expenses that have been already disclosed under the significant expense principle and each reported measure of segment profit and loss. These requirements are in addition to the disclosures that are currently required by Topic 280, Segment reporting . The amendments in this update are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024 and should be applied retrospectively to all periods presented in the financial statements. The implementation of ASU No. 2023-07 will not have an impact on the Company’s financial position, results of operations and cash flow but will impact the Company’s interim and annual segment reporting disclosures. In December 2023, the FASB issued ASU No. 2023-09, Income taxes (Topic 740) Improvement to Income Tax Disclosures . This update requires that public entities on an annual basis disclose specific categories in the rate reconciliation and provide additional information for reconciling items that meet a quantitative threshold. In addition, the amendments in this update require the disclosure on an annual basis of the amount of income taxes paid (net of refund received) disaggregated by federal, state and foreign taxes and the amount of income taxes paid (net of refunds received) disaggregated by individual jurisdictions in which income taxes paid is equal or greater than five percent of total income taxes paid (net of refunds received). This update requires all entities to disclose income (or loss) from continuing operations before income tax expense (or benefit) disaggregated between domestic and foreign and income tax expense (or benefit) from continuing operations disaggregated by federal, state, and foreign. The amendments in this update are effective for annual period beginning after December 15, 2024 and should be applied on a prospective basis. The implementation of ASU No. 2023-09 will not have an impact on the Company’s financial position, results of operations and cash flow but will impact the Company’s annual income tax disclosures. The Organisation for Economic Co-operation and Development (OECD) proposed a global minimum tax of 15 percent on reported profits (entitled “Pillar Two”) that has been agreed upon in principle by over 100 countries. During 2023, many countries took steps to incorporate Pillar Two into their domestic laws. Although the OECD’s model provides a framework for applying the minimum tax, countries may enact Pillar Two rules that vary slightly from the model, can adopt a different timeline, and may adjust local tax incentives in response to Pillar Two. While it is uncertain whether the U.S. will enact legislation to adopt Pillar Two, certain countries in which we operate have enacted such legislation, and other countries are in the process of introducing legislation to implement Pillar Two. We continue to monitor the implementation of Pillar Two in the countries we operate. The Company does not expect Pillar Two to have a material impact on its financial position, results of operations, cash flow and effective tax rate.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Allowance for Doubtful Accounts and Other Accounts Receivable Allowance	The following is an analysis of the allowance for doubtful accounts and other accounts receivable allowances for the years ended December 31, 2023, 2022 and 2021: (In thousands) 2023 2022 2021 Balance at January 1 $ 11,100 $ 10,157 $ 10,133 Provision charged to income 765 1,374 943 Accounts written off, net of recoveries ( 722 ) ( 431 ) ( 919 ) Balance at December 31 $ 11,143 $ 11,100 $ 10,157

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Values and Related Carrying Values of Debt	At December 31, 2023 and 2022 , the fair values and related carrying values of debt, including current maturities, were as follows (the fair value and carrying value amounts are presented without regard to unamortized debt issuance costs of $ 895,000 and $ 686,000 as of December 31, 2023 and 2022, respectively): December 31 (In thousands) 2023 2022 Fair value $ 627,695 $ 541,029 Carrying value 655,041 587,826
Financial Assets and Liabilities, Excluding Cash and Cash Equivalents, Measured on a Recurring Basis at Fair Value	The following tables present financial assets and liabilities, excluding cash and cash equivalents, measured on a recurring basis at fair value as of December 31, 2023 and 2022, and the level within the fair value hierarchy in which the fair value measurement falls: (In thousands) December 31, Level 1 Level 2 Level 3 Mutual fund assets $ 26,804 $ 26,804 $ — $ — Derivative assets: Interest rate contracts 6,183 — 6,183 — Foreign currency contracts 1,018 — 1,018 — Total assets at fair value $ 34,005 $ 26,804 $ 7,201 $ — Derivative liabilities: Foreign currency contracts $ 928 $ — $ 928 $ — (In thousands) December 31, Level 1 Level 2 Level 3 Mutual fund assets $ 23,294 $ 23,294 $ — $ — Derivative assets: Interest rate contracts 8,357 — 8,357 — Foreign currency contracts 513 — 513 — Total assets at fair value $ 32,164 $ 23,294 $ 8,870 $ — Derivative liabilities: Foreign currency contracts $ 525 $ — $ 525 $ —

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in Carrying Value of Goodwill	The changes in the carrying value of goodwill for the years ended December 31, 2023 and 2022, were as follows: Surfactants Polymer Specialty Products Total (In thousands) 2023 2022 2023 2022 2023 2022 2023 2022 Balance as of January 1 Goodwill $ 28,137 $ 25,689 $ 71,747 $ 74,482 $ 483 $ 483 $ 100,367 $ 100,654 Accumulated impairment loss ( 4,445 ) ( 3,467 ) — — — — ( 4,445 ) ( 3,467 ) Goodwill, net 23,692 22,222 71,747 74,482 483 483 95,922 97,187 Goodwill acquired (1) — 1,792 — — — — — 1,792 Goodwill impairment ( 1,060 ) ( 978 ) — — ( 483 ) — ( 1,543 ) ( 978 ) Foreign currency translation 1,644 656 1,419 ( 2,735 ) — — 3,063 ( 2,079 ) Balance as of December 31 Goodwill 29,781 28,137 73,166 71,747 483 483 103,430 100,367 Accumulated impairment loss ( 5,505 ) ( 4,445 ) — — ( 483 ) — ( 5,988 ) ( 4,445 ) Goodwill, net $ 24,276 $ 23,692 $ 73,166 $ 71,747 $ — $ 483 $ 97,442 $ 95,922 (1) See Note 20, Acquisitions , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for information regarding the goodwill acquired in a business combination.
Components of Other Intangible Assets and Changes in Gross Carrying Values	The following table presents the components of other intangible assets, all of which have finite lives, as of December 31, 2023 and 2022. The year-over-year changes in gross carrying values mainly resulted from the effects of foreign currency translation. Gross Carrying Value Accumulated December 31 (3) December 31 (3) (In thousands) 2023 2022 2023 2022 Other Intangible Assets: Patents $ 7,411 $ 7,411 $ 7,063 $ 6,363 Non-compete agreements (2) 401 635 401 548 Trademarks 11,662 11,384 6,705 5,346 Customer lists/relationships (2) 49,157 46,972 16,257 12,491 Know-how (1)(2) 29,543 28,908 15,177 12,536 Total $ 98,174 $ 95,310 $ 45,603 $ 37,284 (1) Know-how includes intellectual property rights covering proprietary information, written formulae, trade secrets or secret processes, inventions and devel opmental products (whether patentable or not), discoveries, improvements, compositions, manufacturing processes, manuals, specifications and technical data. (2) The 2022 balances include intangible assets acquired as part of the Company’s PerformanX acquisition in September 2022. See Note 20, Acquisitions , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for additional details. (3) The 2022 balances do not include gross carrying value and accumulated amortization amounts for intangibles assets that have been fully amortized in prior years. During the fourth quarter of 2023 the Company concluded that the patents related to its Specialty Products segment were impaired as a result of the Company’s decision to exit portions of its Lipid Nutrition business. The Company does not believe that the carrying value of these patents is recoverable. The Company recorded a non-cash charge of $ 495,000 in the Consolidated Statements of Income for the year ended December 31, 2023 on the Goodwill and other intangibles impairment line.
Estimated Amortization Expense for Identifiable Intangibles Assets	Estimated amortization expense for identifiable intangibles assets for each of the five succeeding fiscal years is as follows: (In thousands) For year ended 12/31/24 $ 7,006 For year ended 12/31/25 6,566 For year ended 12/31/26 6,354 For year ended 12/31/27 6,354 For year ended 12/31/28 4,735

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2023
Inventory Disclosure [Abstract]
Composition of Inventories	The composition of inventories was as follows: December 31 (In thousands) 2023 2022 Finished products $ 184,828 $ 250,373 Raw materials 80,730 152,158 Total inventories $ 265,558 $ 402,531

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Debt	At December 31, 2023 and 2022, debt was comprised of the following: (In thousands) Maturity December 31, December 31, Senior unsecured notes 3.95 % (net of unamortized debt issuance cost of $ 191 and 186 for 2023 and 2022, respectively) 2024 - 2027 $ 56,952 $ 71,243 3.86 % (net of unamortized debt issuance cost of $ 105 and 125 for 2023 and 2022, respectively) 2024 - 2025 28,466 42,732 4.86 % (net of unamortized debt issuance cost of $ 0 and 30 for 2023 and 2022 respectively) — — 9,260 2.30 % (net of unamortized debt issuance cost of $ 142 and 122 for 2023 and 2022, respectively) 2024 - 2028 49,858 49,878 2.37 % (net of unamortized debt issuance cost of $ 148 and 128 for 2023 and 2022, respectively) 2024 - 2028 49,852 49,872 2.73 % (net of unamortized debt issuance cost of $ 175 and 55 for 2023 and 2022, respectively) 2025 - 2031 99,825 99,945 2.83 % (net of unamortized debt issuance cost of $ 134 and 40 for 2023 and 2022, respectively) 2026 - 2032 74,866 74,960 Revolving credit facility and term loan borrowing 2024 - 2027 283,000 189,250 Debt of foreign subsidiaries Unsecured bank debt, foreign currency 2024 11,327 — Total debt $ 654,146 $ 587,140 Less current maturities 252,898 132,111 Long-term debt $ 401,248 $ 455,029
Schedule of Net Interest Expense	Net interest expense for the years ended December 31, 2023, 2022 and 2021, comprised the following: (In thousands) 2023 2022 2021 Interest expense $ 29,361 $ 17,852 $ 10,145 Interest income ( 3,843 ) ( 1,080 ) ( 1,255 ) 25,518 16,772 8,890 Capitalized interest ( 13,415 ) ( 6,963 ) ( 3,137 ) Interest expense, net $ 12,103 $ 9,809 $ 5,753

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Schedule of Lease Cost Included in Cost of Sale and Operating Expenses	Lease cost is recognized in both the Cost of Sales and Operating Expenses sections of the Consolidated Statements of Income. (In thousands) Year ended December 31, 2023 Year ended December 31, 2022 Lease Cost Operating lease cost $ 17,820 $ 16,042 Short-term lease cost 10,786 7,029 Variable lease cost 2,354 1,206 Total lease cost $ 30,960 $ 24,277 Other Information Cash paid for amounts included in the Operating cash flow from operating $ 17,838 $ 15,963 Right-of-use assets obtained in exchange 12,134 7,588
Schedule of Maturities of Lease Liabilities	The following table outlines maturities of lease liabilities as of December 31, 2023: (In thousands) Undiscounted Cash Flows: 2024 $ 16,105 2025 11,988 2026 9,201 2027 7,002 2028 6,063 Subsequent to 2028 34,555 Total Undiscounted Cash Flows $ 84,914 Less: Imputed interest ( 13,155 ) Present value $ 71,759 Current operating lease liabilities (1) 13,733 Non-current operating lease liabilities 58,026 Total lease liabilities $ 71,759 (1) This item is included in Accrued liabilities line on the Company’s Consolidated Balance Sheet.
Schedule of Operating Leases Weighted Average, Remaining Lease Term and Discount Rate	Weighted-average remaining lease term-operating leases 9 Years Weighted-average discount rate-operating leases 3.8 %

Other, Net (Tables)

Other, Net (Tables)	12 Months Ended
	Dec. 31, 2023
Other Income and Expenses [Abstract]
Other Net in Consolidated Statements of Income	Other, net in the Consolidated Statements of Income included the following for the years ended December 31, 2023, 2022 and 2021: (In thousands) 2023 2022 2021 Foreign exchange gains (losses) $ ( 3,703 ) $ ( 2,871 ) $ 501 Investment income 859 1,757 2,886 Realized and unrealized gains (losses) on investments 4,314 ( 8,188 ) 2,289 Net periodic benefit cost 28 690 302 Other retirement obligation 383 ( 212 ) 559 Gain on dissolution of the China joint venture — — 972 Other, net $ 1,881 $ ( 8,824 ) $ 7,509

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Provision for Taxes on Income and Other Related Income Before Taxes	The provisions for taxes on income and the related income before taxes for the years ended December 31, 2023, 2022 and 2021, were as follows: (In thousands) 2023 2022 2021 Taxes on Income Federal Current (1) $ ( 22,215 ) $ 39,328 $ 35,057 Deferred (1) 20,268 ( 20,636 ) ( 25,653 ) State Current (1) ( 1,188 ) 9,875 9,320 Deferred (1) 444 ( 6,943 ) ( 6,556 ) Foreign Current 13,287 19,799 23,870 Deferred ( 2,409 ) 127 ( 1,396 ) Total $ 8,187 $ 41,550 $ 34,642 Income before Taxes Domestic $ 11,693 $ 103,831 $ 77,696 Foreign 36,698 84,872 94,841 Total $ 48,391 $ 188,703 $ 172,537 (1) In 2023 for the 2022 U.S. tax returns (federal and state), a U.S. tax accounting method change was made for the 2018-2021 tax years and additional assets that qualified for bonus depreciation under IRC 168(k) were identified. Said items increased the income tax receivable with an offset to current tax expense and created deferred tax liabilities with an offset to deferred tax expense. These amounts were booked in 2023 as a provision-to-return adjustment.
Summary of Variations Between the Effective and Statutory U.S. Federal Income Tax Rates	The variations between the effective and statutory U.S. federal income tax rates are summarized as follows: 2023 (1) 2022 2021 (In thousands) Amount % Amount % Amount % Federal income tax provision at statutory tax rate $ 10,162 21.0 $ 39,628 21.0 $ 36,233 21.0 State income tax provision, less applicable ( 588 ) ( 1.2 ) 2,316 1.2 2,184 1.3 Foreign income taxed at different rates 1,153 2.4 2,417 1.3 2,356 1.4 U.S. taxation of foreign earnings (2) 1,079 2.2 1,616 0.9 ( 134 ) ( 0.1 ) Unrecognized tax benefits (3) 4,090 8.5 3,324 1.8 1,775 1.0 Prior years return to provision true-up (4) ( 2,424 ) ( 5.0 ) ( 1,915 ) ( 1.0 ) ( 3,314 ) ( 1.9 ) Stock based compensation, excess tax benefits ( 1,262 ) ( 2.6 ) ( 580 ) ( 0.3 ) ( 1,287 ) ( 0.7 ) U.S. tax credits (5) ( 4,582 ) ( 9.5 ) ( 4,508 ) ( 2.4 ) ( 2,692 ) ( 1.6 ) Non-deductible expenses and other items, net 559 1.1 ( 748 ) ( 0.5 ) ( 479 ) ( 0.3 ) Total income tax provision $ 8,187 16.9 $ 41,550 22.0 $ 34,642 20.1 (1) In general, all permanent differences, whether positive or negative, have a more pronounced effect on the effective tax rate the lower the pre-tax income even if year-over-year the permanent differences did not change significantly. (2) Includes cost of global intangible low-taxed income (GILTI) in 2023, 2022 and 2021 plus other taxes paid or withheld on cash repatriated from foreign countries in 2023 and 2021. For 2023, see footnote below for the impact of repatriation withholding taxes. For 2023 and 2022, includes Subpart F activity. For 2021, includes the benefit of separate limitation loss foreign tax credit attributes, related to prior years, that were utilized in 2021. (3) For 2023, includes certain tax credits, transfer pricing, and the potential settlement of a foreign jurisdiction audit discussed below. (4) For 2023 and 2022, amount resulted from a higher federal research credit and lower GILTI. For 2021, amount resulted from a higher federal research credit, higher foreign-derived intangible income (FDII), and lower GILTI. (5) For 2023 and 2022, the increase was partially due to certain pilot model design and engineering costs.
Schedule Showing Tax Effects of Significant Temporary Differences Representing Deferred Tax Assets and Liabilities	At December 31, 2023 and 2022, the tax effects of significant temporary differences representing deferred tax assets and liabilities were as follows: (In thousands) 2023 2022 Deferred Tax Assets: Pensions $ 446 $ 144 Deferred revenue 2,640 3,483 Other accruals and reserves 14,638 13,949 Legal and environmental accruals 7,292 10,283 Deferred compensation 12,199 13,845 Bad debt and rebate reserves 4,916 3,729 Non-U.S. subsidiaries net operating loss carryforwards 6,512 3,634 Amortization of intangibles 37,123 28,311 Inventories 8,959 10,577 Tax credit carryforwards 13,682 8,183 $ 108,407 $ 96,138 Deferred Tax Liabilities: Depreciation $ ( 82,907 ) $ ( 52,130 ) Unrealized foreign exchange loss ( 2,784 ) ( 3,603 ) Other ( 2,991 ) ( 3,064 ) $ ( 88,682 ) $ ( 58,797 ) Valuation Allowance $ ( 853 ) $ ( 836 ) Net Deferred Tax Assets $ 18,872 $ 36,505 Reconciliation to Consolidated Balance Sheet: Non-current deferred tax assets (in other non-current assets) 29,245 46,684 Non-current deferred tax liabilities ( 10,373 ) ( 10,179 ) Net Deferred Tax Assets $ 18,872 $ 36,505
Schedule of Reconciliations of Unrecognized Tax Benefits	Below are reconciliations of the January 1 and December 31 balances of unrecognized tax benefits for 2023, 2022 and 2021: (In thousands) 2023 2022 2021 Unrecognized tax benefits, opening balance $ 10,682 $ 7,292 $ 4,735 Gross increases – tax positions in prior period 1,891 2,188 938 Gross increases – current period tax positions 2,139 1,617 1,662 Settlements/State voluntary disclosure ( 343 ) ( 454 ) — Foreign currency translation 241 74 ( 14 ) Lapse of statute of limitations ( 20 ) ( 35 ) ( 29 ) Unrecognized tax benefits, ending balance $ 14,590 $ 10,682 $ 7,292

Stock-based Compensation (Table

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Fair Value Assumptions for Stock Options	The following are the weighted-average assumptions used to calculate the grant-date fair values of stock option awards granted in the years ended December 31, 2023, 2022 and 2021: For the Years Ended December 31 2023 2022 2021 Expected dividend yield 1.19 % 1.18 % 1.30 % Expected volatility 31.29 % 32.27 % 31.81 % Expected term 7.2 years 6.0 years 7.3 years Risk-free interest rate 4.03 % 1.93 % 0.96 %
Summary of Stock Option Activity	A summary of stock option activity for the year ended December 31, 2023 is presented below: Shares Weighted- Weighted- Aggregate Value Options Outstanding at January 1, 2023 427,161 $ 82.53 Granted 2,777 106.85 Exercised ( 52,999 ) 54.24 Forfeited ( 8,800 ) 113.81 Outstanding at December 31, 2023 368,139 86.03 4.72 $ 3,135 Vested or expected to vest at December 31, 2023 368,139 86.03 4.72 3,135 Exercisable at December 31, 2023 363,949 85.79 4.68 3,186
Summary of Stock Award Activity	A summary of stock award activity for the year ended December 31, 2023, is presented below: Shares Weighted-Average Stock Awards Unvested at January 1, 2023 103,969 $ 110.50 Granted 88,130 104.96 Vested ( 29,906 ) 116.41 Forfeited/modified due to change of assumptions ( 95,407 ) 106.68 Unvested at December 31, 2023 66,786 106.00
Summary of SARs Activity	The following is a summary of SARs activity for the year ended December 31, 2023: Shares Weighted- Weighted- Aggregate SARs Outstanding at January 1, 2023 850,156 $ 94.49 Granted 77,006 108.64 Exercised ( 38,988 ) 61.97 Forfeited ( 56,255 ) 112.46 Outstanding at December 31, 2023 831,919 96.11 5.94 $ —

Postretirement Benefit Plans (T

Postretirement Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items]
Obligations and Funded Status	Obligations and Funded Status at December 31 United States United Kingdom (In thousands) 2023 2022 2023 2022 Change in benefit obligation Benefit obligation at beginning of year $ 130,467 $ 174,863 $ 13,286 $ 23,276 Interest cost 6,949 4,923 669 374 Actuarial (income) loss 3,634 ( 40,420 ) ( 92 ) ( 7,333 ) Benefits paid ( 9,267 ) ( 8,899 ) ( 804 ) ( 709 ) Foreign exchange impact — — 691 ( 2,322 ) Benefit obligation at end of year $ 131,783 $ 130,467 $ 13,750 $ 13,286 United States United Kingdom (In thousands) 2023 2022 2023 2022 Change in plan assets Fair value of plan assets at beginning of year $ 136,744 $ 178,574 $ 15,163 $ 27,464 Actual return on plan assets 10,237 ( 33,187 ) 470 ( 9,393 ) Employer contributions 271 256 464 536 Benefits paid ( 9,267 ) ( 8,899 ) ( 804 ) ( 709 ) Foreign exchange impact — — 798 ( 2,735 ) Fair value of plan assets at end of year $ 137,985 $ 136,744 $ 16,091 $ 15,163 Over funded status at end of year $ 6,202 $ 6,277 $ 2,341 $ 1,877
Schedule of Amounts Recognized in Balance Sheets	The amounts recognized in the consolidated balance sheets at December 31 consisted of: United States United Kingdom (In thousands) 2023 2022 2023 2022 Non-current assets $ 8,627 $ 8,700 $ 2,341 $ 1,877 Current liability ( 308 ) ( 278 ) — — Non-current liability ( 2,117 ) ( 2,145 ) — — Net amount recognized $ 6,202 $ 6,277 $ 2,341 $ 1,877
Amounts Recognized in Accumulated Other Comprehensive Income	The amounts recognized in accumulated other comprehensive income at December 31 consisted of: United States United Kingdom (In thousands) 2023 2022 2023 2022 Net actuarial loss $ 20,755 $ 18,801 $ 5,989 $ 6,188
Components of Net Periodic Benefit Cost	Net periodic benefit costs for the years ended December 31, 2023, 2022 and 2021, were as follows: United States United Kingdom (In thousands) 2023 2022 2021 2023 2022 2021 Interest cost $ 6,949 $ 4,923 $ 4,671 $ 669 $ 374 $ 357 Expected return on plan assets ( 8,533 ) ( 8,802 ) ( 10,348 ) ( 695 ) ( 399 ) ( 320 ) Amortization of net actuarial (gain) loss ( 23 ) 2,277 4,444 334 9 129 Net periodic benefit cost $ ( 1,607 ) $ ( 1,602 ) $ ( 1,233 ) $ 308 $ ( 16 ) $ 166
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income	Other changes in plan assets and benefit obligations recognized in other comprehensive income for the years ended December 31, 2023, 2022 and 2021, were as follows: United States United Kingdom (In thousands) 2023 2022 2021 2023 2022 2021 Net actuarial (gain) loss $ 1,930 $ 1,570 $ ( 9,793 ) $ 135 $ 2,430 $ ( 757 ) Amortization of net actuarial gain (loss) 23 ( 2,277 ) ( 4,444 ) ( 334 ) ( 9 ) ( 129 ) Total recognized in other comprehensive $ 1,953 $ ( 707 ) $ ( 14,237 ) $ ( 199 ) $ 2,421 $ ( 886 ) Total recognized in net periodic benefit $ 346 $ ( 2,309 ) $ ( 15,470 ) $ 109 $ 2,405 $ ( 720 )
Estimated Future Benefit Payments	Estimated Future Benefit Payments (In thousands) United United 2024 $ 9,646 $ 606 2025 9,841 628 2026 10,023 671 2027 10,126 698 2028 10,158 733 2029-2033 49,888 4,116
Defined Contribution Expenses for Company's Qualified Defined Contribution Plans and Statutory Profit Sharing Contributions	Defined contribution expenses for the Company’s qualified defined contribution plans and statutory profit sharing contributions were as follows: (In thousands) 2023 2022 2021 Retirement contributions $ 8,930 $ 8,556 $ 8,134 Profit sharing contributions 2,019 5,276 5,081 Total $ 10,949 $ 13,832 $ 13,215
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Company's Asset Allocations for its U.S. and U.K Pension Plans	The Company’s asset allocations for its U.S. pension plans at December 31, 2023 and 2022, by asset category, were as follows: December 31, 2023 (In thousands) Level 1 Level 2 Level 3 Total Cash and Cash Equivalents $ 8,196 $ — $ — $ 8,196 Equity Securities U.S. Equities 14,942 — — 14,942 Non-U.S. Equities — — — — Employer Securities 12,316 — — 12,316 Total Equities 27,258 — — 27,258 Fixed Income Securities U.S. Corporate Bonds — 57,595 — 57,595 U.S. Government and Agency Bonds 30,278 3,533 — 33,811 Other Bonds — 11,125 — 11,125 Total Fixed Income 30,278 72,253 — 102,531 Total $ 65,732 $ 72,253 $ — $ 137,985 December 31, 2022 (In thousands) Level 1 Level 2 Level 3 Total Cash and Cash Equivalents $ 7,531 $ — $ — $ 7,531 Equity Securities U.S. Equities 21,279 — — 21,279 Non-U.S. Equities 9,788 — — 9,788 Employer Securities 17,970 — — 17,970 Total Equities 49,037 — — 49,037 Fixed Income Securities U.S. Corporate Bonds — 51,444 — 51,444 U.S. Government and Agency Bonds 15,627 2,628 — 18,255 Other Bonds — 10,477 — 10,477 Total Fixed Income 15,627 64,549 — 80,176 Total $ 72,195 $ 64,549 $ — $ 136,744
United Kingdom [Member]
Defined Benefit Plan Disclosure [Line Items]
Company's Asset Allocations for its U.S. and U.K Pension Plans	The Company’s asset allocations for its U.K. pension plans at December 31, 2023 and 2022, by asset category, were as follows: December 31, 2023 (In thousands) Level 1 Level 2 Level 3 Total Cash — $ 1,308 $ — $ 1,308 Equity Securities Pooled Pension Funds — 1,017 — 1,017 Fixed Income Pooled Pension Funds — 12,860 — 12,860 Real Estate Pooled Pension Funds — 146 — 146 Insurance Contracts — — 760 760 Total $ — $ 15,331 $ 760 $ 16,091 December 31, 2022 (In thousands) Level 1 Level 2 Level 3 Total Cash $ — $ 1,448 $ — $ 1,448 Equity Securities Pooled Pension Funds — 1,688 — 1,688 Fixed Income Pooled Pension Funds — 11,350 — 11,350 Insurance Contracts — — 677 677 Total $ — $ 14,486 $ 677 $ 15,163
Fair Value Changes within Asset Categories for which Fair Value Measurements Use Significant Unobservable Inputs (Level 3) Defined Benefit United States Plans and United Kingdom Plans	Fair value changes within asset categories for which fair value measurements use significant unobservable inputs (Level 3) were as follows during 2023 and 2022: (In thousands) Insurance Contracts Fair value, December 31, 2021 $ 1,003 Sale proceeds (benefit payments) ( 104 ) Change in unrealized gain ( 120 ) Foreign exchange impact ( 102 ) Fair value, December 31, 2022 $ 677 Sale proceeds (benefit payments) ( 123 ) Change in unrealized gain 169 Foreign exchange impact 37 Fair value, December 31, 2023 $ 760
Defined Benefit Plan Periodic Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-Average Assumptions Used to Determine Benefit Obligations/Net Periodic Benefit Costs	The weighted-average assumptions used to determine net periodic benefit costs for years ended December 31 were as follows: United States United Kingdom 2023 2022 2021 2023 2022 2021 Discount rate 5.50 % 2.90 % 2.60 % 5.00 % 1.80 % 1.40 % Expected long-term return on plan assets 5.50 % 5.50 % 6.75 % 4.47 % 1.61 % 1.13 %
Benefit Obligation [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-Average Assumptions Used to Determine Benefit Obligations/Net Periodic Benefit Costs	The weighted-average assumptions used to determine benefit obligations at December 31 were as follows: United States United Kingdom 2023 2022 2023 2022 Discount rate 5.20 % 5.50 % 4.80 % 5.00 %

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Payables and Accruals [Abstract]
Composition of Accrued Liabilities	The composition of accrued liabilities was as follows: December 31 (In thousands) 2023 2022 Accrued payroll and benefits $ 48,459 $ 73,713 Accrued customer rebates 21,024 24,715 Other accrued liabilities 52,458 64,384 Total accrued liabilities $ 121,941 $ 162,812 The decrease in accrued payroll and benefits was mainly due to lower incentive-based compensation expense accruals.

Other Non-Current Liabilities (

Other Non-Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Other Liabilities Disclosure [Abstract]
Composition of Other Non-Current Liabilities	The composition of other non-current liabilities was as follows: December 31 (In thousands) 2023 2022 Deferred revenue $ 6,647 $ 8,762 Environmental and legal matters 8,491 16,276 Deferred compensation liability 27,607 32,459 Pension liability 5,430 5,241 Other non-current liabilities 21,172 17,953 Total other non-current liabilities $ 69,347 $ 80,691

Segment Reporting (Tables)

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2023
Segment Reporting [Abstract]
Operating Segment	The following is segment data for the three years ended December 31, 2023, 2022 and 2021: (In thousands) Surfactants Polymers Specialty Segment 2023 Net sales $ 1,602,819 $ 642,471 $ 80,478 $ 2,325,768 Operating income 72,399 60,770 11,476 144,645 Assets 1,586,148 537,193 70,508 2,193,849 Capital expenditures 231,341 19,971 9,310 260,622 Depreciation and amortization expenses 64,377 32,426 5,789 102,592 2022 Net sales $ 1,882,745 $ 789,080 $ 101,445 $ 2,773,270 Operating income 162,746 82,897 29,895 275,538 Assets 1,579,242 565,726 96,193 2,241,161 Capital expenditures 259,442 35,679 4,926 300,047 Depreciation and amortization expenses 55,262 31,399 5,807 92,468 2021 Net sales $ 1,562,795 $ 713,440 $ 69,731 $ 2,345,966 Operating income 165,999 73,591 14,178 253,768 Assets 1,245,207 556,799 78,100 1,880,106 Capital expenditures 154,953 29,077 4,976 189,006 Depreciation and amortization expenses 51,375 30,598 5,836 87,809
Reconciliation of Segment Information to Consolidated Financial Statements	Below are reconciliations of segment data to the consolidated financial statements: (In thousands) 2023 2022 2021 Operating income - segment totals $ 144,645 $ 275,538 $ 253,768 Goodwill and other intangibles impairment (3)(4) ( 2,038 ) — — Business restructuring, assets impairment and loss on asset (1) ( 11,968 ) ( 308 ) ( 3,353 ) Unallocated corporate expenses (2) ( 72,026 ) ( 67,894 ) ( 79,634 ) Total operating income 58,613 207,336 170,781 Interest expense, net ( 12,103 ) ( 9,809 ) ( 5,753 ) Other, net 1,881 ( 8,824 ) 7,509 Consolidated income before income taxes $ 48,391 $ 188,703 $ 172,537 Assets - segment totals $ 2,193,849 $ 2,241,161 $ 1,880,106 Unallocated corporate assets 169,505 192,011 185,506 Consolidated assets $ 2,363,354 $ 2,433,172 $ 2,065,612 Capital expenditures - segment totals $ 260,622 $ 300,047 $ 189,006 Unallocated corporate expenditures ( 287 ) 1,506 5,476 Consolidated capital expenditures $ 260,335 $ 301,553 $ 194,482 Depreciation and amortization expenses – segment totals $ 102,592 $ 92,468 $ 87,809 Unallocated corporate depreciation expenses 2,746 2,182 3,067 Consolidated depreciation and amortization expenses $ 105,338 $ 94,650 $ 90,876 (1) See Note 22, Business Restructuring, Assets Impairment and Asset Disposition , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) regarding business restructuring and asset disposition costs. (2) Unallocated corporate expenses are primarily comprised of corporate administrative expenses (e.g., corporate finance, legal, human resources, information technology, deferred compensation and environmental remediation) that are not included in segment operating income and not used to evaluate segment performance. (3) See Note 4, Goodwill and Other Intangibles Assets , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) regarding goodwill and other intangibles impairment. (4) 2023 Goodwill and other intangibles impairment expenses and 2023, 2022 and 2021 business restructuring, assets impairment and loss on asset disposition expenses were excluded from segment results.
Summary of company-wide geographic data	Below is certain Company-wide geographic data for the years ended December 31, 2023, 2022 and 2021: (In thousands) 2023 2022 2021 Net sales (1) United States $ 1,312,866 $ 1,579,194 $ 1,297,650 France 202,038 227,421 179,746 Poland 171,889 195,781 198,883 United Kingdom 174,574 229,836 208,780 Brazil 124,661 175,004 136,799 Mexico 144,163 148,858 127,944 All other countries 195,577 217,176 196,164 Total $ 2,325,768 $ 2,773,270 $ 2,345,966 Long-lived assets (2) United States $ 1,007,337 $ 896,867 $ 668,362 Netherlands 80,335 79,007 85,931 Germany 41,878 42,512 41,438 Singapore 17,617 20,899 23,507 Brazil 39,512 38,493 35,294 China 25,704 28,717 30,991 United Kingdom 33,857 33,389 38,634 Mexico 73,449 52,917 45,384 All other countries 36,989 34,444 39,034 Total $ 1,356,678 $ 1,227,245 $ 1,008,575 (1) Net sales are attributed to countries based on the location of the Company legal entity making the sale. (2) Includes net property, plant and equipment, goodwill and other intangible assets.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Share	Below is the computation of basic and diluted earnings per share for the years ended December 31, 2023, 2022 and 2021: (In thousands, except per share amounts) 2023 2022 2021 Computation of Basic Earnings per Share Net income attributable to Stepan Company $ 40,204 $ 147,153 $ 137,804 Weighted-average number of shares outstanding 22,777 22,781 22,922 Basic earnings per share $ 1.77 $ 6.46 $ 6.01 Computation of Diluted Earnings per Share Net income attributable to Stepan Company $ 40,204 $ 147,153 $ 137,804 Weighted-average number of shares outstanding 22,777 22,781 22,922 Add weighted-average net shares from assumed (1) 66 104 138 Add weighted-average net shares related to unvested 3 1 1 Add weighted-average net shares from assumed 67 111 166 Add weighted-average contingently issuable net shares 33 67 60 Weighted-average shares applicable to diluted 22,946 23,064 23,287 Diluted earnings per share $ 1.75 $ 6.38 $ 5.92 (1) Options/SARs to purchase 672,485 , 343,715 and 103,182 shares of the Company’s common stock were excluded from the computations of diluted earnings per share for the years ended December 31, 2023, 2022 and 2021 , respectively. The options’/SARs’ exercise prices were greater than the average market price for the Company’s common stock and inclusion of the instruments would have had an antidilutive effect on the computations of earnings per share.

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Summary of Changes in Accumulated Other Comprehensive Income (Loss)	Below is the change in the Company’s accumulated other comprehensive income (loss) (AOCI) balance by component (net of income taxes) for the years ended December 31, 2023, 2022 and 2021: (In thousands) Foreign Defined Cash Flow Total Balance at December 31, 2020 $ ( 107,083 ) $ ( 29,861 ) $ 63 $ ( 136,881 ) Other comprehensive income before reclassifications ( 28,185 ) 8,188 — ( 19,997 ) Amounts reclassified from AOCI — 3,651 ( 9 ) 3,642 Net current period other comprehensive income ( 28,185 ) 11,839 ( 9 ) ( 16,355 ) Balance at December 31, 2021 $ ( 135,268 ) $ ( 18,022 ) $ 54 $ ( 153,236 ) Other comprehensive income before reclassifications ( 21,567 ) ( 2,857 ) 8,357 ( 16,067 ) Amounts reclassified from AOCI — 1,800 ( 9 ) 1,791 Net current period other comprehensive income ( 21,567 ) ( 1,057 ) 8,348 ( 14,276 ) Balance at December 31, 2022 $ ( 156,835 ) $ ( 19,079 ) $ 8,402 $ ( 167,512 ) Other comprehensive income before reclassifications 40,423 ( 1,630 ) ( 2,174 ) 36,619 Amounts reclassified from AOCI — 301 ( 10 ) 291 Net current period other comprehensive income 40,423 ( 1,329 ) ( 2,184 ) 36,910 Balance at December 31, 2023 $ ( 116,412 ) $ ( 20,408 ) $ 6,218 $ ( 130,602 )
Summary of Amounts Reclassified Out of Accumulated Other Comprehensive Income	Amounts reclassified out of AOCI for the three years ended December 31, 2023, 2022 and 2021, is displayed below: Amounts Reclassified from AOCI (1) (In thousands) 2023 2022 2021 Affected Line Item in Amortization of defined pension items: Prior service cost $ ( 10 ) $ ( 9 ) $ ( 12 ) Actuarial loss ( 392 ) ( 2,393 ) ( 4,800 ) $ ( 402 ) ( 2,402 ) ( 4,812 ) Total before tax (2) 101 602 1,161 Tax benefit $ ( 301 ) $ ( 1,800 ) $ ( 3,651 ) Net of tax Gains and losses on cash flow hedges: Foreign exchange contracts $ 10 $ 9 $ 9 Cost of sales 10 9 9 Total before tax — — — Tax benefit $ 10 $ 9 $ 9 Net of tax Total reclassifications for the period $ ( 291 ) $ ( 1,791 ) $ ( 3,642 ) Net of tax (1) Amounts in parentheses denote expense to the Company’s Consolidated Statements of Income. (2) This component of accumulated other comprehensive income is included in the computation of net periodic benefit cost (see Note 13, Postretirement Benefit Plans , of the notes to the Company’s consolidated financial statements for details regarding net periodic benefit costs for the Company’s U.S. and U.K. defined benefit plans).

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2023
2021 Acquisitions [Member]
Business Acquisition [Line Items]
Summary of Purchase Price Allocation for Acquisition	The following table summarizes the purchase price allocation for the major components of the acquisition: (In thousands) Assets: Property, plant and equipment $ 54,200 Identifiable intangibles assets 46,000 Goodwill 64,800 Total assets acquired $ 165,000

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Geographic Disaggregation of Net Sales	The tables below provide a geographic disaggregation of net sales for the years ended December 31, 2023, 2022 and 2021. The Company’s business segmentation by geographic region most effectively captures the nature and economic characteristics of the Company’s revenue streams impacted by economic factors. 2023 (In thousands) Surfactants Polymers Specialty Total Geographic Market North America $ 949,218 $ 338,979 $ 66,802 $ 1,354,999 Europe 289,010 259,491 13,414 561,915 Latin America 304,870 1,112 262 306,244 Asia 59,721 42,889 — 102,610 Total $ 1,602,819 $ 642,471 $ 80,478 $ 2,325,768 2022 (In thousands) Surfactants Polymers Specialty Total Geographic Market North America $ 1,099,616 $ 437,312 $ 83,807 1,620,735 Europe 349,651 307,441 16,118 673,210 Latin America 363,799 4,629 1,520 369,948 Asia 69,679 39,698 — 109,377 Total $ 1,882,745 $ 789,080 $ 101,445 $ 2,773,270 2021 (In thousands) Surfactants Polymers Specialty Total Geographic Market North America $ 904,469 $ 364,382 $ 59,461 1,328,312 Europe 288,735 302,137 9,152 600,024 Latin America 299,601 3,823 1,118 304,542 Asia 69,990 43,098 — 113,088 Total $ 1,562,795 $ 713,440 $ 69,731 $ 2,345,966

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, MMBTU in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) MMBTU Country Subsidiary Customer $ / shares	Dec. 31, 2022 USD ($) Customer	Dec. 31, 2021 USD ($) Customer
Summary Of Significant Accounting Policy [Line Items]
Cash and cash equivalents	$ 129,823,000	$ 173,750,000
Single customer comprised more than 10 percent of the Company's consolidated net sales | Customer	0	0	0
Deferred compensation liability	$ 39,847,000	$ 43,005,000
Percentage of deferred compensation liability related to performance common stock	34%	34%
Increase in market price of common stock due to deferred compensation | $ / shares	$ 1
Decrease in market price of common stock due to deferred compensation | $ / shares	$ 1
Additional compensation expense, Increase	$ 143,000
Additional compensation expense, Decrease	143,000
Cost of maintenance and repairs	80,226,000	$ 82,110,000	$ 75,351,000
Total research and development expenses	$ 35,732,000	40,902,000	$ 38,778,000
Capitalized Environmental expenditures depreciation period	10 years
Indefinite-life intangible assets	$ 0
Number of foreign subsidiaries | Subsidiary	4
Percentage of global minimum tax on reported profits	15%
Number of countries | Country	100
Natural Gas [Member]
Summary Of Significant Accounting Policy [Line Items]
Volume in derivative contract | MMBTU	0.7
Purchased Contract Price	$ 3,403,000
Building [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	30 years
Building Improvements [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	15 years
Minimum [Member]
Summary Of Significant Accounting Policy [Line Items]
Concentration risk Payment terms extended	30 days
Percentage of Tax benefit recognized	50%
Minimum [Member] | Patents [Member]
Summary Of Significant Accounting Policy [Line Items]
Finite-lived intangible asset, useful life	15 years
Minimum [Member] | Trademarks [Member]
Summary Of Significant Accounting Policy [Line Items]
Finite-lived intangible asset, useful life	8 years
Minimum [Member] | Customer Relationships [Member]
Summary Of Significant Accounting Policy [Line Items]
Finite-lived intangible asset, useful life	10 years
Minimum [Member] | Know-how [Member]
Summary Of Significant Accounting Policy [Line Items]
Finite-lived intangible asset, useful life	7 years
Minimum [Member] | Manufacturing Equipment [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	10 years
Minimum [Member] | Furniture and Fixtures [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	5 years
Minimum [Member] | Vehicles [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	3 years
Minimum [Member] | Computers Equipment And Software [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	3 years
Maximum [Member]
Summary Of Significant Accounting Policy [Line Items]
Concentration risk Payment terms extended	60 days
Maximum [Member] | Trademarks [Member]
Summary Of Significant Accounting Policy [Line Items]
Finite-lived intangible asset, useful life	11 years
Maximum [Member] | Customer Relationships [Member]
Summary Of Significant Accounting Policy [Line Items]
Finite-lived intangible asset, useful life	20 years
Maximum [Member] | Know-how [Member]
Summary Of Significant Accounting Policy [Line Items]
Finite-lived intangible asset, useful life	20 years
Maximum [Member] | Manufacturing Equipment [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	15 years
Maximum [Member] | Furniture and Fixtures [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	10 years
Maximum [Member] | Vehicles [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	5 years
Maximum [Member] | Computers Equipment And Software [Member]
Summary Of Significant Accounting Policy [Line Items]
Lives used for calculating depreciation expense	10 years
Money Market Funds [Member]
Summary Of Significant Accounting Policy [Line Items]
Cash and cash equivalents	$ 15,117,000	64,851,000
Demand Deposits And Certifates of Deposit [Member]
Summary Of Significant Accounting Policy [Line Items]
Cash and cash equivalents	6,374,000	11,811,000
Non-U.S. Subsidiaries [Member]
Summary Of Significant Accounting Policy [Line Items]
Cash and cash equivalents	$ 108,332,000	$ 97,088,000
Nanjing Stepan Jinling Chemical Limited Liability Company [Member]
Summary Of Significant Accounting Policy [Line Items]
Ownership percentage			80%

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Allowance for Doubtful Accounts and Other Accounts Receivable Allowances (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Allowance, balance at the beginning	$ 11,100	$ 10,157	$ 10,133
Provision charged to income	765	1,374	943
Accounts written off, net of recoveries	(722)	(431)	(919)
Allowance, balance at ending	$ 11,143	$ 11,100	$ 10,157

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Unamortized debt issuance cost	$ 895,000	$ 686,000

Fair Value Measurements - Fair

Fair Value Measurements - Fair Values and Related Carrying Values of Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Carrying value	$ 655,041	$ 587,826
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value	$ 627,695	$ 541,029

Fair Value Measurements - Finan

Fair Value Measurements - Financial Assets and Liabilities, Excluding Cash and Cash Equivalents, Measured on a Recurring Basis at Fair Value (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Mutual fund assets	$ 26,804	$ 23,294
Derivative assets:
Interest rate contracts	6,183	8,357
Foreign currency contracts	1,018	513
Total assets at fair value	34,005	32,164
Derivative liabilities:
Foreign currency contracts	928	525
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Mutual fund assets	26,804	23,294
Derivative assets:
Total assets at fair value	26,804	23,294
Level 2 [Member]
Derivative assets:
Interest rate contracts	6,183	8,357
Foreign currency contracts	1,018	513
Total assets at fair value	7,201	8,870
Derivative liabilities:
Foreign currency contracts	$ 928	$ 525

Derivative Instruments - Additi

Derivative Instruments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount	$ 106,561,000	$ 56,746,000
Revolving Credit Facility [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Debt Instrument, Maturity Date	Jun. 24, 2027
Cash Flow Hedging [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative notional amount	$ 100,000,000
Maturity date of current interest swap contract	Mar. 10, 2027
Minimum [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative foreign currency exchange contracts durations	1 month
Maximum [Member]
Derivative Instruments And Hedging Activities Disclosures [Line Items]
Derivative foreign currency exchange contracts durations	5 months

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Value of Goodwill (Detail) - USD ($)		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022
Goodwill [Line Items]
Goodwill, Beginning Balance		$ 100,367,000	$ 100,654,000
Accumulated impairment loss, Beginning Balance		(4,445,000)	(3,467,000)
Goodwill net, Beginning Balance		95,922,000	97,187,000
Goodwill acquired	[1]		1,792,000
Goodwill impairment		(1,543,000)	(978,000)
Foreign currency translation		3,063,000	(2,079,000)
Goodwill, Ending Balance		103,430,000	100,367,000
Accumulated impairment loss, Ending Balance		(5,988,000)	(4,445,000)
Goodwill net, Ending Balance		97,442,000	95,922,000
Surfactants Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance		28,137,000	25,689,000
Accumulated impairment loss, Beginning Balance		(4,445,000)	(3,467,000)
Goodwill net, Beginning Balance		23,692,000	22,222,000
Goodwill acquired	[1]		1,792,000
Goodwill impairment		(1,060,000)	(978,000)
Foreign currency translation		1,644,000	656,000
Goodwill, Ending Balance		29,781,000	28,137,000
Accumulated impairment loss, Ending Balance		(5,505,000)	(4,445,000)
Goodwill net, Ending Balance		24,276,000	23,692,000
Polymer Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance		71,747,000	74,482,000
Goodwill net, Beginning Balance		71,747,000	74,482,000
Foreign currency translation		1,419,000	(2,735,000)
Goodwill, Ending Balance		73,166,000	71,747,000
Goodwill net, Ending Balance		73,166,000	71,747,000
Specialty Products Segment [Member]
Goodwill [Line Items]
Goodwill, Beginning Balance		483,000	483,000
Goodwill net, Beginning Balance		483,000	483,000
Goodwill impairment		(483,000)
Goodwill, Ending Balance		483,000	483,000
Accumulated impairment loss, Ending Balance		$ (483,000)
Goodwill net, Ending Balance			$ 483,000
[1] See Note 20, Acquisitions , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for information regarding the goodwill acquired in a business combination.

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Goodwill [Line Items]
Goodwill	$ 97,442,000	$ 95,922,000	$ 97,187,000
Goodwill impairment	1,543,000	978,000
Amortization of Intangible Assets, Total	7,368,000	6,835,000	7,292,000
Specialty Products [Member]
Goodwill [Line Items]
Goodwill		483,000	483,000
Goodwill impairment	483,000
Impairment expenses	495,000
Surfactants Segment [Member]
Goodwill [Line Items]
Goodwill	24,276,000	23,692,000	$ 22,222,000
Goodwill impairment	1,060,000	978,000
Philippines Reporting Unit [Member] | Surfactants Segment [Member]
Goodwill [Line Items]
Goodwill impairment		$ 978,000
Colombia Reporting Unit [Member] | Surfactants Segment [Member]
Goodwill [Line Items]
Goodwill impairment	1,060,000
Mexico Reporting Unit [Member]
Goodwill [Line Items]
Goodwill	6,652,000
Goodwill impairment	$ 0
Basis point increase in discount rate not result in impairment	1%
Decrease in multiple used in market-based computation result in impairment	1.5

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Components of Other Intangible Assets and Changes in Gross Carrying Values (Detail) - USD ($) $ in Thousands		Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Other Finite-Lived Intangible Assets, Gross Carrying Value	[1]	$ 98,174	$ 95,310
Other Finite-Lived Intangible Assets, Accumulated Amortization	[1]	45,603	37,284
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Other Finite-Lived Intangible Assets, Gross Carrying Value	[1]	7,411	7,411
Other Finite-Lived Intangible Assets, Accumulated Amortization	[1]	7,063	6,363
Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Other Finite-Lived Intangible Assets, Gross Carrying Value	[1],[2]	401	635
Other Finite-Lived Intangible Assets, Accumulated Amortization	[1],[2]	401	548
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Other Finite-Lived Intangible Assets, Gross Carrying Value	[1]	11,662	11,384
Other Finite-Lived Intangible Assets, Accumulated Amortization	[1]	6,705	5,346
Customer Lists/relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Other Finite-Lived Intangible Assets, Gross Carrying Value	[1],[2]	49,157	46,972
Other Finite-Lived Intangible Assets, Accumulated Amortization	[1],[2]	16,257	12,491
Know-how [Member]
Finite-Lived Intangible Assets [Line Items]
Other Finite-Lived Intangible Assets, Gross Carrying Value	[1],[2],[3]	29,543	28,908
Other Finite-Lived Intangible Assets, Accumulated Amortization	[1],[2],[3]	$ 15,177	$ 12,536
[1] The 2022 balances do not include gross carrying value and accumulated amortization amounts for intangibles assets that have been fully amortized in prior years. The 2022 balances include intangible assets acquired as part of the Company’s PerformanX acquisition in September 2022. See Note 20, Acquisitions , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) for additional details. Know-how includes intellectual property rights covering proprietary information, written formulae, trade secrets or secret processes, inventions and devel opmental products (whether patentable or not), discoveries, improvements, compositions, manufacturing processes, manuals, specifications and technical data.

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets - Estimated Amortization Expense for Identifiable Intangibles Assets (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
For year ended 12/31/24	$ 7,006
For year ended 12/31/25	6,566
For year ended 12/31/26	6,354
For year ended 12/31/27	6,354
For year ended 12/31/28	$ 4,735

Inventories - Composition of In

Inventories - Composition of Inventories (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Finished products	$ 184,828	$ 250,373
Raw materials	80,730	152,158
Total inventories	$ 265,558	$ 402,531

Debt - Debt (Detail)

Debt - Debt (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Total debt	$ 654,146	$ 587,140
Less current maturities	252,898	132,111
Long-term debt, less current maturities (Note 6)	401,248	455,029
Revolving credit facility and term loan borrowing [Member]
Debt Instrument [Line Items]
Short-term debt	$ 283,000	$ 189,250
Minimum [Member] | Revolving credit facility and term loan borrowing [Member]
Debt Instrument [Line Items]
Maturity Dates	2024	2024
Maximum [Member] | Revolving credit facility and term loan borrowing [Member]
Debt Instrument [Line Items]
Maturity Dates	2027	2027
Unsecured private placement 3.95% note [Member]
Debt Instrument [Line Items]
Total debt	$ 56,952	$ 71,243
Debt instrument interest rate percentage	3.95%	3.95%
Unsecured private placement 3.95% note [Member] | Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2024	2024
Unsecured private placement 3.95% note [Member] | Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2027	2027
Unsecured private placement 3.86% note [Member]
Debt Instrument [Line Items]
Total debt	$ 28,466	$ 42,732
Debt instrument interest rate percentage	3.86%	3.86%
Unsecured private placement 3.86% note [Member] | Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2024	2024
Unsecured private placement 3.86% note [Member] | Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2025	2025
Unsecured private placement 4.86% note [Member]
Debt Instrument [Line Items]
Total debt		$ 9,260
Debt instrument interest rate percentage	4.86%	4.86%
Unsecured private placement 2.30% note [Member]
Debt Instrument [Line Items]
Total debt	$ 49,858	$ 49,878
Debt instrument interest rate percentage	2.30%	2.30%
Unsecured private placement 2.30% note [Member] | Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2024	2024
Unsecured private placement 2.30% note [Member] | Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2028	2028
Unsecured private placement 2.37% note [Member]
Debt Instrument [Line Items]
Total debt	$ 49,852	$ 49,872
Debt instrument interest rate percentage	2.37%	2.37%
Unsecured private placement 2.37% note [Member] | Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2024	2024
Unsecured private placement 2.37% note [Member] | Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2028	2028
Unsecured private placement 2.73% note [Member]
Debt Instrument [Line Items]
Total debt	$ 99,825	$ 99,945
Debt instrument interest rate percentage	2.73%	2.73%
Unsecured private placement 2.73% note [Member] | Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2025	2025
Unsecured private placement 2.73% note [Member] | Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2031	2031
Unsecured private placement 2.83% note [Member]
Debt Instrument [Line Items]
Total debt	$ 74,866	$ 74,960
Debt instrument interest rate percentage	2.83%	2.83%
Unsecured private placement 2.83% note [Member] | Minimum [Member]
Debt Instrument [Line Items]
Maturity Dates	2026	2026
Unsecured private placement 2.83% note [Member] | Maximum [Member]
Debt Instrument [Line Items]
Maturity Dates	2032	2032
Debt of foreign subsidiaries Unsecured bank debt, foreign currency [Member]
Debt Instrument [Line Items]
Total debt	$ 11,327
Maturity Dates	2024	2024

Debt - Debt (Parenthetical) (De

Debt - Debt (Parenthetical) (Detail) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Unamortized debt issuance cost	$ 895,000	$ 686,000
Unsecured private placement 3.95% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	191,000	186,000
Unsecured private placement 3.86% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	105,000	125,000
Unsecured private placement 4.86% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	0	30,000
Unsecured private placement 2.30% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	142,000	122,000
Unsecured private placement 2.37% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	148,000	128,000
Unsecured private placement 2.73% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	175,000	55,000
Unsecured private placement 2.83% note [Member]
Debt Instrument [Line Items]
Unamortized debt issuance cost	$ 134,000	$ 40,000

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)			12 Months Ended
	Sep. 29, 2023	Jun. 24, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Total debt			$ 654,146,000	$ 587,140,000
Term loan principal repaid			$ 37,858,000	37,857,000	$ 37,858,000
Line of credit facility, Minimum maturity period			1 month
Line of credit facility, maturity period			3 months
Line of credit facility, Maximum maturity period			6 months
Debt matures in 2024			$ 252,898,000
Debt matures in 2025			69,108,000
Debt matures in 2026			66,786,000
Debt matures in 2027			135,535,000
Debt matures in 2028			45,000,000
Debt matures after 2028			85,714,000
Amount of repayments of long-term debt due in next year			$ 53,571,000
Minimum [Member]
Debt Instrument [Line Items]
Commitment fee percentage			0.125%
Minimum [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Spread rate			1.125%
Minimum [Member] | Prime Rate [Member]
Debt Instrument [Line Items]
Spread rate			0.125%
Maximum [Member]
Debt Instrument [Line Items]
Commitment fee percentage			0.25%
Maximum [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Spread rate			1.75%
Maximum [Member] | Prime Rate [Member]
Debt Instrument [Line Items]
Spread rate			0.75%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date			Jun. 24, 2027
Delayed Draw Term Loan Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit agreement			$ 95,000,000
Term loan principal repaid			5,000,000,000
Unsecured Private Placement Notes [Member]
Debt Instrument [Line Items]
Total debt			$ 359,819,000
Debt instrument maturity dates description			The notes had original maturities of seven to 12 years with mandatory principal payments beginning four, five and six years after issuance.
Unsecured Private Placement Notes [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt instrument interest rate percentage			2.30%
Maturity Dates			7 years
Unsecured Private Placement Notes [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt instrument interest rate percentage			3.95%
Maturity Dates			12 years
Note Purchase Agreements [Member]
Debt Instrument [Line Items]
Percentage of unrestricted and unencumbered foreign-based cash	65%
Percentage of debt instruments rating fee	0.75%
Multi-Currency Credit Facility with Syndicate of Banks [Member]
Debt Instrument [Line Items]
Revolving credit agreement		$ 450,000,000
Committed multi-currency credit facility, maturity date		Jun. 24, 2027
Multi-Currency Credit Facility with Syndicate of Banks [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit agreement		$ 350,000,000
Multi-Currency Credit Facility with Syndicate of Banks [Member] | Delayed Draw Term Loan Credit Facility [Member]
Debt Instrument [Line Items]
Revolving credit agreement		100,000,000
Multi Currency Revolving Credit Agreement [Member]
Debt Instrument [Line Items]
Revolving credit agreement		$ 350,000,000
Letters of Credit Outstanding			$ 10,877,000
Unused Revolving credit			151,123,000
Outstanding borrowings, including term loan			283,000,000
Unrestricted retained earnings			234,399,000	$ 224,189,000
Debt of foreign subsidiaries Unsecured bank debt and Term Loan, foreign currency [Member]
Debt Instrument [Line Items]
Total debt			$ 11,327,000

Debt - Schedule of Net Interest

Debt - Schedule of Net Interest Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Interest Income (Expense), Net [Abstract]
Interest expense	$ 29,361	$ 17,852	$ 10,145
Interest income	(3,843)	(1,080)	(1,255)
Interest expense net of interest income	25,518	16,772	8,890
Capitalized interest	(13,415)	(6,963)	(3,137)
Interest expense, net	$ 12,103	$ 9,809	$ 5,753

Leases - Additional Information

Leases - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023 USD ($) Country
Operating Leased Assets [Line Items]
Operating Lease, Liability	$ 71,759,000
Number of countries leases reside | Country	5
Percentage of value of leases reside	98%
Minimum [Member]
Operating Leased Assets [Line Items]
Lessee, operating lease, term of contract	1 year
Maximum [Member]
Operating Leased Assets [Line Items]
Lessee, operating lease, term of contract	10 years
Railcars [Member]
Operating Leased Assets [Line Items]
Percentage of lease asset categories	33%
Railcars [Member] | Maximum [Member]
Operating Leased Assets [Line Items]
Lessee, operating lease, term of contract	7 years
Real Estate [Member]
Operating Leased Assets [Line Items]
Percentage of lease asset categories	52%
Real Estate [Member] | Minimum [Member]
Operating Leased Assets [Line Items]
Lessee, operating lease, term of contract	1 year
Real Estate [Member] | Maximum [Member]
Operating Leased Assets [Line Items]
Lessee, operating lease, term of contract	50 years
Railcar and Storage Tank Leases [Member]
Operating Leased Assets [Line Items]
Operating lease, lease not yet commenced	$ 292,000

Leases - Schedule of Lease Cost

Leases - Schedule of Lease Cost Recognized in both Cost of Sale and Operating Expenses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Lease Cost
Operating lease cost	$ 17,820	$ 16,042
Short-term lease cost	10,786	7,029
Variable lease cost	2,354	1,206
Total lease cost	30,960	24,277
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flow from operating leases	17,838	15,963
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 12,134	$ 7,588

Leases - Schedule of Lease Liab

Leases - Schedule of Lease Liability Payments (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
2024	$ 16,105
2025	11,988
2026	9,201
2027	7,002
2028	6,063
Subsequent to 2028	34,555
Total Undiscounted Cash Flows	84,914
Less: Imputed interest	(13,155)
Present value	71,759
Current operating lease liabilities	$ 13,733
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued liabilities (Note 14)
Non-current operating lease liabilities	$ 58,026	$ 50,559
Total lease liabilities	$ 71,759

Leases - Schedule of Operating

Leases - Schedule of Operating Leases Weighted Average, Remaining Lease Term and Discount Rate (Detail)	Dec. 31, 2023
Leases [Abstract]
Weighted-average remaining lease term-operating leases	9 years
Weighted-average discount rate-operating leases	3.80%

Other, Net - Other Net in Conso

Other, Net - Other Net in Consolidated Statements of Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Other Nonoperating Income (Expense) [Abstract]
Foreign exchange gains (losses)	$ (3,703)	$ (2,871)	$ 501
Investment income	859	1,757	2,886
Realized and unrealized gains (losses) on investments	4,314	(8,188)	2,289
Net periodic benefit cost	28	690	302
Other retirement obligation	383	(212)	559
Gain on dissolution of the China joint venture			972
Other, net	$ 1,881	$ (8,824)	$ 7,509

Income Taxes - Schedule of Prov

Income Taxes - Schedule of Provision for Taxes on Income and Other Related Income Before Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Federal
Current	$ (22,215)	$ 39,328	$ 35,057
Deferred	20,268	(20,636)	(25,653)
State
Current	(1,188)	9,875	9,320
Deferred	444	(6,943)	(6,556)
Foreign
Current	13,287	19,799	23,870
Deferred	(2,409)	127	(1,396)
Total	8,187	41,550	34,642
Income before Taxes
Domestic	11,693	103,831	77,696
Foreign	36,698	84,872	94,841
Income Before Provision for Income Taxes	$ 48,391	$ 188,703	$ 172,537

Income Taxes - Summary of Varia

Income Taxes - Summary of Variations Between the Effective and Statutory U.S. Federal Income Tax Rates (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Federal income tax provision at statutory tax rate	$ 10,162	$ 39,628	$ 36,233
State income tax provision, less applicable federal tax benefit	(588)	2,316	2,184
Foreign income taxed at different rates	1,153	2,417	2,356
U.S. taxation of foreign earnings	1,079	1,616	(134)
Unrecognized tax benefits	4,090	3,324	1,775
Prior years return to provision true-up	(2,424)	(1,915)	(3,314)
Stock based compensation, excess tax benefits	(1,262)	(580)	(1,287)
U.S. tax credits	(4,582)	(4,508)	(2,692)
Non-deductible expenses and other items, net	559	(748)	(479)
Total	$ 8,187	$ 41,550	$ 34,642
Percentage of Federal income tax provision at statutory tax rate	21%	21%	21%
Percentage of state income tax provision, less applicable federal tax benefit	(1.20%)	1.20%	1.30%
Percentage of Foreign income taxed at different rates	2.40%	1.30%	1.40%
Percentage of U.S. taxation of foreign earnings	2.20%	0.90%	(0.10%)
Percentage of Unrecognized tax benefits	8.50%	1.80%	1%
Percentage of Prior years return to provision true-up	(5.00%)	(1.00%)	(1.90%)
Percentage of stock based compensation, excess tax benefits	(2.60%)	(0.30%)	(0.70%)
Percentage of U.S. tax credits	(9.50%)	(2.40%)	(1.60%)
Non-deductible expenses and other items, net	1.10%	(0.50%)	(0.30%)
Percentage of Total income tax provision	16.90%	22%	20.10%

Income Taxes - Schedule Showing

Income Taxes - Schedule Showing Tax Effects of Significant Temporary Differences Representing Deferred Tax Assets and Liabilities (Detail) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Deferred Tax Assets:
Pensions	$ 446,000	$ 144,000
Deferred revenue	2,640,000	3,483,000
Other accruals and reserves	14,638,000	13,949,000
Legal and environmental accruals	7,292,000	10,283,000
Deferred compensation	12,199,000	13,845,000
Bad debt and rebate reserves	4,916,000	3,729,000
Non-U.S. subsidiaries net operating loss carryforwards	6,512,000	3,634,000
Amortization of intangibles	37,123,000	28,311,000
Inventories	8,959,000	10,577,000
Tax credit carryforwards	13,682,000	8,183,000
Deferred Tax Assets, Gross	108,407,000	96,138,000
Deferred Tax Liabilities:
Depreciation	(82,907,000)	(52,130,000)
Unrealized foreign exchange loss	(2,784,000)	(3,603,000)
Other	(2,991,000)	(3,064,000)
Deferred Tax Liabilities, Gross	(88,682,000)	(58,797,000)
Valuation Allowance	(853,000)	(836,000)
Net Deferred Tax Assets	18,872,000	36,505,000
Reconciliation to Consolidated Balance Sheet:
Non-current deferred tax assets (in other non-current assets)	29,245,000	46,684,000
Non-current deferred tax liabilities	$ (10,373,000)	$ (10,179,000)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Deduction percentage of dividends received from distribution to earnings previously taxed	100%
Increase in effective tax rate	0.8
Foreign earnings repatriated	$ 54,944,000,000
Incremental tax expense	397,000,000
Tax loss carryforwards	20,113,000	$ 10,754,000
Tax credit carryforwards	13,682,000	8,183,000
Capital loss carryforwards	608,000	595,000
Valuation Allowance	853,000	836,000
Unrecognized tax benefits	14,590,000	10,682,000	$ 7,292,000	$ 4,735,000
Unrecognized tax benefits that, if recognized, would impact effective tax rates	14,056,000	10,172,000	6,973,000
Net interest and penalty expense (income)	435,000	202,000	$ 260,000
Income tax liability for interest and penalties	$ 978,000	$ 543,000

Income Taxes - Schedule of Reco

Income Taxes - Schedule of Reconciliations of Unrecognized Tax Benefits (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Unrecognized tax benefits, opening balance	$ 10,682,000	$ 7,292,000	$ 4,735,000
Gross increases – tax positions in prior period	1,891,000	2,188,000	938,000
Gross increases – current period tax positions	2,139,000	1,617,000	1,662,000
Settlements/State voluntary disclosure	(343,000)	(454,000)
Foreign currency translation	241,000	74,000	(14,000)
Lapse of statute of limitations	(20,000)	(35,000)	(29,000)
Unrecognized tax benefits, ending balance	$ 14,590,000	$ 10,682,000	$ 7,292,000

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Class Of Stock [Line Items]
Treasury stock, shares	4,628,072	4,605,858
Shares purchased during period		251,120	135,103
Treasury stock distributed under deferred compensation plan	20,448
Stock purchased to settle employees statutory withholding taxes relates to performance stock awards and deferred compensation distribution	42,662
Open Market Repurchases [Member]
Class Of Stock [Line Items]
Shares purchased during period	0

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of common stock authorized for share based payment awards under 2011 Plan	500,000
Shares available for grant under the 2011 plan	716,012
Compensation expenses	$ 5,741,000	$ 13,851,000	$ 11,716,000
Income tax benefit recognized in the income statement for share-based compensation arrangements	$ 1,452,000	3,537,000	2,867,000
Weighted average period for amortization of unrecognized compensation cost	1 year 8 months 12 days
Proceeds from stock option exercises	$ 2,795,000	$ 782,000	$ 1,369,000
Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period of expiration	10 years
Weighted-average grant-date fair values of options awarded	$ 38.72	$ 32.21	$ 36.49
Intrinsic values of options exercised	$ 2,364,000	$ 475,000	$ 1,287,000
Unrecognized compensation cost	127,000
Actual tax benefit recognized for the tax deductions from stock based compensation	$ 330,000	$ 36,000	$ 172,000
Stock Option Granted Prior to 2017 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	2 years
Stock Options Granted in 2017 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of awards vesting in each year	33.33%
Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost	$ 3,761,000
Weighted average period for amortization of unrecognized compensation cost	1 year 8 months 12 days
Performance RSUs vested	29,906
Weighted-average grant-date fair values of awards granted	$ 104.96	$ 106.78	$ 119.76
SARs [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Period of expiration	10 years
Unrecognized compensation cost	$ 3,648,000
Weighted average period for amortization of unrecognized compensation cost	1 year 7 months 6 days
Weighted-average grant-date fair values of awards granted	$ 38.98	$ 34.76	$ 36.49
SARs Granted Prior to 2017 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	2 years
SARs Granted in 2017 [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of awards vesting in each year	33.33%

Stock-based Compensation - Fair

Stock-based Compensation - Fair Value Assumptions for Stock Options (Detail) - Stock Option [Member]	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected dividend yield	1.19%	1.18%	1.30%
Expected volatility	31.29%	32.27%	31.81%
Expected term	7 years 2 months 12 days	6 years	7 years 3 months 18 days
Risk-free interest rate	4.03%	1.93%	0.96%

Stock-based Compensation - Summ

Stock-based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Shares, Beginning Balance	427,161
Granted, Shares	2,777
Exercised, Shares	(52,999)	(11,888)	(20,435)
Forfeited, Shares	(8,800)
Shares, Ending Balance	368,139	427,161
Vested or expected to vest, Shares	368,139
Exercisable, Shares	363,949
Weighted Average Exercise Price, Beginning Balance	$ 82.53
Granted, Weighted Average Exercise Price	106.85
Exercised, Weighted Average Exercise Price	54.24
Forfeited, Weighted Average Exercise Price	113.81
Weighted Average Exercise Price, Ending Balance	86.03	$ 82.53
Vested or expected to vest, Weighted Average Exercise Price	86.03
Exercisable, Weighted Average Exercise Price	$ 85.79
Weighted Average Remaining Contractual Term, Ending Balance	4 years 8 months 19 days
Vested or expected to vest, Weighted Average Remaining Contractual Term	4 years 8 months 19 days
Exercisable, Weighted Average Remaining Contractual Term	4 years 8 months 4 days
Aggregate Intrinsic Value, Ending Balance	$ 3,135
Vested or expected to vest, Aggregate Intrinsic Value	3,135
Exercisable, Aggregate Intrinsic Value	$ 3,186

Stock-based Compensation - Su_2

Stock-based Compensation - Summary of Stock Award Activity (Detail) - Stock Awards [Member] - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Beginning Balance	103,969
Granted, Shares	88,130
Vested, Shares	(29,906)
Forfeited/Modified due to change of assumptions, Shares	(95,407)
Shares, Ending Balance	66,786	103,969
Unvested Weighted Average Grant Date Fair Value, Beginning Balance	$ 110.5
Granted, Weighted Average Grant Date Fair Value	104.96	$ 106.78	$ 119.76
Vested, Weighted Average Grant Date Fair Value	116.41
Forfeited/Modified due to change of assumptions, Weighted Average Grand Date Fair Value	106.68
Unvested Weighted Average Grant Date Fair Value, Ending Balance	$ 106	$ 110.5

Stock-based Compensation - Su_3

Stock-based Compensation - Summary of SARs Activity (Detail) - SARs [Member]	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares, Beginning Balance | shares	850,156
Granted, Shares | shares	77,006
Exercised, Shares | shares	(38,988)
Forfeited, Shares | shares	(56,255)
Shares, Ending Balance | shares	831,919
Weighted Average Exercise Price, Beginning Balance | $ / shares	$ 94.49
Granted, Weighted Average Exercise Price | $ / shares	108.64
Exercised, Weighted Average Exercise Price | $ / shares	61.97
Forfeited, Weighted Average Exercise Price | $ / shares	112.46
Weighted Average Exercise Price, Ending balance | $ / shares	$ 96.11
Weighted Average Remaining Contractual Term, Ending balance	5 years 11 months 8 days

Deferred Compensation - Additio

Deferred Compensation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-Based Payment Arrangement [Abstract]
Deferred compensation	$ 4,371,000	$ (9,393,000)	$ 6,895,000
Deferred compensation liability	$ 39,847,000	$ 43,005,000
Increase (decrease) in market price of common stock due to deferred compensation	$ (11.91)

Postretirement Benefit Plans -

Postretirement Benefit Plans - Obligations and Funded Status (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Benefit obligation at beginning of year	$ 130,467	$ 174,863
Interest cost	6,949	4,923	$ 4,671
Actuarial (income) loss	3,634	(40,420)
Benefits paid	(9,267)	(8,899)
Benefit obligation at end of year	131,783	130,467	174,863
Fair value of plan assets at beginning of year	136,744	178,574
Actual return on plan assets	10,237	(33,187)
Employer contributions	271	256
Benefits paid	(9,267)	(8,899)
Fair value of plan assets at end of year	137,985	136,744	178,574
Over funded status at end of year	6,202	6,277
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Benefit obligation at beginning of year	13,286	23,276
Interest cost	669	374	357
Actuarial (income) loss	(92)	(7,333)
Benefits paid	(804)	(709)
Foreign exchange impact	691	(2,322)
Benefit obligation at end of year	13,750	13,286	23,276
Fair value of plan assets at beginning of year	15,163	27,464
Actual return on plan assets	470	(9,393)
Employer contributions	464	536
Benefits paid	(804)	(709)
Foreign exchange impact	798	(2,735)
Fair value of plan assets at end of year	16,091	15,163	$ 27,464
Over funded status at end of year	$ 2,341	$ 1,877

Postretirement Benefit Plans _2

Postretirement Benefit Plans - Schedule of Amounts Recognized in Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Non-current asset	$ 8,627	$ 8,700
Current liability	(308)	(278)
Non-current liability	(2,117)	(2,145)
Net amount recognized	6,202	6,277
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Non-current asset	2,341	1,877
Net amount recognized	$ 2,341	$ 1,877

Postretirement Benefit Plans _3

Postretirement Benefit Plans - Amounts Recognized in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial loss	$ 20,755	$ 18,801
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial loss	$ 5,989	$ 6,188

Postretirement Benefit Plans _4

Postretirement Benefit Plans - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	$ 28	$ 690	$ 302
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	6,949	4,923	4,671
Expected return on plan assets	(8,533)	(8,802)	(10,348)
Amortization of net actuarial (gain) loss	(23)	2,277	4,444
Net periodic benefit cost	(1,607)	(1,602)	(1,233)
United Kingdom [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	669	374	357
Expected return on plan assets	(695)	(399)	(320)
Amortization of net actuarial (gain) loss	334	9	129
Net periodic benefit cost	$ 308	$ (16)	$ 166

Postretirement Benefit Plans _5

Postretirement Benefit Plans - Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial (gain) loss	$ 1,930	$ 1,570	$ (9,793)
Amortization of net actuarial gain (loss)	23	(2,277)	(4,444)
Total recognized in other comprehensive income	1,953	(707)	(14,237)
Total recognized in net periodic benefit cost and other comprehensive income	346	(2,309)	(15,470)
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Net actuarial (gain) loss	135	2,430	(757)
Amortization of net actuarial gain (loss)	(334)	(9)	(129)
Total recognized in other comprehensive income	(199)	2,421	(886)
Total recognized in net periodic benefit cost and other comprehensive income	$ 109	$ 2,405	$ (720)

Postretirement Benefit Plans _6

Postretirement Benefit Plans - Estimated Future Benefit Payments (Detail) $ in Thousands	Dec. 31, 2023 USD ($)
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
2024	$ 9,646
2025	9,841
2026	10,023
2027	10,126
2028	10,158
2029-2033	49,888
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
2024	606
2025	628
2026	671
2027	698
2028	733
2029-2033	$ 4,116

Postretirement Benefit Plans _7

Postretirement Benefit Plans - Weighted-Average Assumptions Used To Determine Benefit Obligations (Detail)	Dec. 31, 2023	Dec. 31, 2022
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	5.20%	5.50%
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	4.80%	5%

Postretirement Benefit Plans _8

Postretirement Benefit Plans - The Weighted Average Assumptions Used to Determine Net Periodic Benefit Costs (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
United States [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	5.50%	2.90%	2.60%
Expected long-term return on plan assets	5.50%	5.50%	6.75%
United Kingdom [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	5%	1.80%	1.40%
Expected long-term return on plan assets	4.47%	1.61%	1.13%

Postretirement Benefit Plans _9

Postretirement Benefit Plans - Defined Benefit Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Feb. 15, 2023	Feb. 17, 2022	Feb. 24, 2021
Defined Benefit Plan Disclosure [Line Items]
Assets gains or losses added for prior year	80%
Assets gains or losses added for second preceding year	60%
Assets gains or losses added for third preceding year	40%
Assets gains or losses added for fourth preceding year	20%
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Common shares sold to the Company's ESOP trust				38,542	33,983	31,362
Expected long-term rate of return on assets	5.50%	5.50%	6.75%
Expected payment related to qualified plan	$ 0
Expected payment related to non-qualified plan	$ 308,000
U.K Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on assets	4.47%	1.61%	1.13%
Percentage of premium estimated return for equities and properties to risk free rate	3%
Percentage of long term return in cash	5.25%
Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for investment category	13%
Percentage of target allocation for investment including stock category	20%
Expected long-term rate of return on assets	9.57%
Equities [Member] | U.K Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for investment category	6%
Real Estate [Member] | U.K Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for investment category	1%
Bonds [Member] | U.K Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for investment category	80%
Debt Securities [Member] | United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for investment category	78%
Cash [Member] | United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for investment category	2%
Cash [Member] | U.K Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for investment category	8%
Insurance Contracts [Member] | U.K Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of target allocation for investment category	5%
U.S. and international equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on assets	5.35%

Postretirement Benefit Plans_10

Postretirement Benefit Plans - Company's Asset Allocations for its U.S. Pension Plans by Asset Category (Detail) - United States [Member] - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Total	$ 137,985	$ 136,744	$ 178,574
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	65,732	72,195
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	72,253	64,549
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	8,196	7,531
Cash and Cash Equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	8,196	7,531
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	27,258	49,037
Equity Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	27,258	49,037
U.S. Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	14,942	21,279
U.S. Equities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	14,942	21,279
Non-U.S. Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total		9,788
Non-U.S. Equities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	0	9,788
Employer Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	12,316	17,970
Employer Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	12,316	17,970
Fixed Income Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	102,531	80,176
Fixed Income Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	30,278	15,627
Fixed Income Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	72,253	64,549
U.S. Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	57,595	51,444
U.S. Corporate Bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	57,595	51,444
U.S. Government and Agency Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	33,811	18,255
U.S. Government and Agency Bonds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	30,278	15,627
U.S. Government and Agency Bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	3,533	2,628
Other Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	11,125	10,477
Other Bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	$ 11,125	$ 10,477

Postretirement Benefit Plans_11

Postretirement Benefit Plans - Company's Asset Allocations for its U.K. Pension Plans by Asset Category (Detail) - United Kingdom [Member] - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Total	$ 16,091	$ 15,163	$ 27,464
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	15,331	14,486
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	760	677
Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	1,308	1,448
Cash [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	1,308	1,448
Pooled Pension Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	1,017	1,688
Pooled Pension Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	1,017	1,688
Pooled Fixed Pension Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	12,860	11,350
Pooled Fixed Pension Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	12,860	11,350
Real Estate Pooled Pension Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	146
Real Estate Pooled Pension Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	146
Insurance Contracts [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	760	677
Insurance Contracts [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	$ 760	$ 677

Postretirement Benefit Plans_12

Postretirement Benefit Plans - Fair Value Changes Within Asset Categories for which Fair Value Measurements Use Significant Unobservable Inputs Level 3 (Detail) - Insurance Contracts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 677	$ 1,003
Sale proceeds (benefit payments)	(123)	(104)
Change in unrealized gain	169	(120)
Foreign exchange impact	37	(102)
Ending balance	$ 760	$ 677

Postretirement Benefit Plans_13

Postretirement Benefit Plans - Defined Contribution Expenses for Company's Qualified Defined Contribution Plans and Statutory Profit Sharing Contributions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Contribution Plan Disclosure [Line Items]
Total defined contribution expense	$ 10,949	$ 13,832	$ 13,215
Retirement Contributions [Member]
Defined Contribution Plan Disclosure [Line Items]
Total defined contribution expense	8,930	8,556	8,134
Profit Sharing Contributions [Member]
Defined Contribution Plan Disclosure [Line Items]
Total defined contribution expense	$ 2,019	$ 5,276	$ 5,081

Postretirement Benefit Plans_14

Postretirement Benefit Plans - Defined Contribution Plans - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Contribution Plan Disclosure [Line Items]
Supplemental plan liability balances	$ 450,000	$ 446,000
Defined contribution plan expense	$ 10,949,000	13,832,000	$ 13,215,000
Percentage of union and non-union employees eligible for either statutory or Company's sponsored profit sharing contributions	85%
Percentage of us based union and non-union employees eligible for either statutory or Company's sponsored profit sharing contributions	100%
Statutory Plans [Member]
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan expense	$ 480,000	421,000	$ 219,000
Defined Contribution Plans [Member]
Defined Contribution Plan Disclosure [Line Items]
Balance of trust assets	$ 450,000	$ 376,000

Accrued Liabilities - Compositi

Accrued Liabilities - Composition of Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Payables and Accruals [Abstract]
Accrued payroll and benefits	$ 48,459	$ 73,713
Accrued customer rebates	21,024	24,715
Other accrued liabilities	52,458	64,384
Total accrued liabilities	$ 121,941	$ 162,812

Other Non-Current Liabilities -

Other Non-Current Liabilities - Statement of Composition of Other Non Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Other Liabilities Disclosure [Abstract]
Deferred revenue	$ 6,647	$ 8,762
Environmental and legal matters	8,491	16,276
Deferred compensation liability	27,607	32,459
Pension liability	5,430	5,241
Other non-current liabilities	21,172	17,953
Total other non-current liabilities	$ 69,347	$ 80,691

Contingencies - Additional Info

Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Site Contingency [Line Items]
Environmental losses accrual	$ 20,646,000	$ 32,628,000
Cash expenditures related to legal and environmental matters	$ 13,224,000	$ 2,330,000
Contribution for future response costs	5%
Wilmington Site [Member]
Site Contingency [Line Items]
Payment of environmental response costs	$ 3,648,000
Minimum [Member]
Site Contingency [Line Items]
Environmental losses and legal losses	20,646,000
Maximum [Member]
Site Contingency [Line Items]
Environmental losses and legal losses	$ 49,351,000

Segment Reporting - Additional

Segment Reporting - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023 Segment
Segment Reporting [Abstract]
Number of reportable segments	3

Segment Reporting - Operating S

Segment Reporting - Operating Segment (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Net sales	[1]	$ 2,325,768	$ 2,773,270	$ 2,345,966
Operating income		58,613	207,336	170,781
Assets		2,363,354	2,433,172	2,065,612
Depreciation and amortization expenses		105,338	94,650	90,876
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales		2,325,768	2,773,270	2,345,966
Operating income		144,645	275,538	253,768
Assets		2,193,849	2,241,161	1,880,106
Capital expenditures		260,622	300,047	189,006
Depreciation and amortization expenses		102,592	92,468	87,809
Surfactants [Member]
Segment Reporting Information [Line Items]
Net sales		1,602,819	1,882,745	1,562,795
Surfactants [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales		1,602,819	1,882,745	1,562,795
Operating income		72,399	162,746	165,999
Assets		1,586,148	1,579,242	1,245,207
Capital expenditures		231,341	259,442	154,953
Depreciation and amortization expenses		64,377	55,262	51,375
Polymers [Member]
Segment Reporting Information [Line Items]
Net sales		642,471	789,080	713,440
Polymers [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales		642,471	789,080	713,440
Operating income		60,770	82,897	73,591
Assets		537,193	565,726	556,799
Capital expenditures		19,971	35,679	29,077
Depreciation and amortization expenses		32,426	31,399	30,598
Specialty Products [Member]
Segment Reporting Information [Line Items]
Net sales		80,478	101,445	69,731
Specialty Products [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Net sales		80,478	101,445	69,731
Operating income		11,476	29,895	14,178
Assets		70,508	96,193	78,100
Capital expenditures		9,310	4,926	4,976
Depreciation and amortization expenses		$ 5,789	$ 5,807	$ 5,836
[1] Includes net property, plant and equipment, goodwill and other intangible assets.

Segment Reporting - Reconciliat

Segment Reporting - Reconciliation of Segment Information to Consolidated Financial Statements (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Operating income		$ 58,613	$ 207,336	$ 170,781
Goodwill and other intangibles impairment		2,038	978
Business restructuring, assets impairment and loss on asset disposition	[1]	(11,968)	(308)	(3,353)
Interest expense, net		(12,103)	(9,809)	(5,753)
Other, net		1,881	(8,824)	7,509
Consolidated income before income taxes		48,391	188,703	172,537
Assets		2,363,354	2,433,172	2,065,612
Consolidated capital expenditures		260,335	301,553	194,482
Depreciation and amortization		105,338	94,650	90,876
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating income		144,645	275,538	253,768
Goodwill and other intangibles impairment	[2],[3]	2,038
Assets		2,193,849	2,241,161	1,880,106
Capital expenditures		260,622	300,047	189,006
Depreciation and amortization		102,592	92,468	87,809
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Unallocated corporate expenses	[4]	(72,026)	(67,894)	(79,634)
Unallocated corporate assets		169,505	192,011	185,506
Unallocated corporate expenditures		(287)	1,506	5,476
Unallocated corporate depreciation expenses		$ 2,746	$ 2,182	$ 3,067
[1] See Note 22, Business Restructuring, Assets Impairment and Asset Disposition , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) regarding business restructuring and asset disposition costs. 2023 Goodwill and other intangibles impairment expenses and 2023, 2022 and 2021 business restructuring, assets impairment and loss on asset disposition expenses were excluded from segment results. See Note 4, Goodwill and Other Intangibles Assets , of the notes to the Company’s consolidated financial statements (included in Item 8 of this Form 10-K) regarding goodwill and other intangibles impairment. Unallocated corporate expenses are primarily comprised of corporate administrative expenses (e.g., corporate finance, legal, human resources, information technology, deferred compensation and environmental remediation) that are not included in segment operating income and not used to evaluate segment performance.

Segment Reporting - Summary of

Segment Reporting - Summary of Company Wide Geographic Data (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023		Dec. 31, 2022		Dec. 31, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	[1]	$ 2,325,768		$ 2,773,270		$ 2,345,966
Long-lived assets	[1]	1,356,678		1,227,245		1,008,575
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	[1]	1,312,866		1,579,194		1,297,650
Long-lived assets	[2]	1,007,337		896,867		668,362
France [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	[2]	202,038		227,421		179,746
Poland [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	[2]	171,889		195,781		198,883
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	[2]	174,574		229,836		208,780
Long-lived assets	[1]	33,857		33,389		38,634
All Other Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	[2]	195,577		217,176		196,164
Long-lived assets	[1]	36,989		34,444		39,034
Mexico [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	[1]	144,163		148,858		127,944
Long-lived assets		73,449	[2]	52,917	[1]	45,384	[1]
Brazil [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	[2]	124,661		175,004		136,799
Long-lived assets	[1]	39,512		38,493		35,294
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	[1]	41,878		42,512		41,438
Singapore [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	[1]	17,617		20,899		23,507
Netherlands [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	[1]	80,335		79,007		85,931
China [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets	[1]	$ 25,704		$ 28,717		$ 30,991
[1] Includes net property, plant and equipment, goodwill and other intangible assets. Net sales are attributed to countries based on the location of the Company legal entity making the sale.

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Computation of Basic Earnings per Share
Net income attributable to Stepan Company		$ 40,204	$ 147,153	$ 137,804
Weighted-average number of shares outstanding		22,777	22,781	22,922
Basic earnings per share		$ 1.77	$ 6.46	$ 6.01
Computation of Diluted Earnings per Share
Net income attributable to Stepan Company		$ 40,204	$ 147,153	$ 137,804
Weighted-average number of shares outstanding		22,777	22,781	22,922
Add weighted-average net shares related to unvested stock awards (under treasury share method)		3	1	1
Weighted-average shares applicable to diluted earnings		22,946	23,064	23,287
Diluted earnings per share		$ 1.75	$ 6.38	$ 5.92
Stock Option [Member]
Computation of Diluted Earnings per Share
Add weighted-average net shares from assumed exercise of options (under treasury share method)	[1]	66	104	138
Stock Appreciation Rights (SARs)
Computation of Diluted Earnings per Share
Add weighted-average net shares from assumed exercise of options (under treasury share method)		67	111	166
Performance Stock Award [Member]
Computation of Diluted Earnings per Share
Add weighted-average net shares from assumed exercise of options (under treasury share method)		33	67	60
[1] Options/SARs to purchase 672,485 , 343,715 and 103,182 shares of the Company’s common stock were excluded from the computations of diluted earnings per share for the years ended December 31, 2023, 2022 and 2021 , respectively. The options’/SARs’ exercise prices were greater than the average market price for the Company’s common stock and inclusion of the instruments would have had an antidilutive effect on the computations of earnings per share.

Earnings Per Share - Computat_2

Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Parenthetical) (Detail) - shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Options and Stock Appreciation Rights (SARs) [Member]
Earnings Per Share Basic [Line Items]
Options/SARs to purchase shares of common stock were excluded from the computations of diluted earnings per share	672,485	343,715	103,182

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 1,166,065
Ending Balance	1,216,490	$ 1,166,065
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(156,835)	(135,268)	$ (107,083)
Other comprehensive income before reclassifications	40,423	(21,567)	(28,185)
Net current period other comprehensive income	40,423	(21,567)	(28,185)
Ending Balance	(116,412)	(156,835)	(135,268)
Defined Benefit Pension Plan Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(19,079)	(18,022)	(29,861)
Other comprehensive income before reclassifications	(1,630)	(2,857)	8,188
Amounts reclassified from AOCI	301	1,800	3,651
Net current period other comprehensive income	(1,329)	(1,057)	11,839
Ending Balance	(20,408)	(19,079)	(18,022)
Cash Flow Hedge Adjustments [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	8,402	54	63
Other comprehensive income before reclassifications	(2,174)	8,357
Amounts reclassified from AOCI	(10)	(9)	(9)
Net current period other comprehensive income	(2,184)	8,348	(9)
Ending Balance	6,218	8,402	54
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	(167,512)	(153,236)	(136,881)
Other comprehensive income before reclassifications	36,619	(16,067)	(19,997)
Amounts reclassified from AOCI	291	1,791	3,642
Net current period other comprehensive income	36,910	(14,276)	(16,355)
Ending Balance	$ (130,602)	$ (167,512)	$ (153,236)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income (Loss) - Summary of Amounts Reclassified Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income Before Provision for Income Taxes		$ 48,391	$ 188,703	$ 172,537
Tax benefit		(8,187)	(41,550)	(34,642)
Cost of Sales		2,048,170	2,346,201	1,950,156
Defined Benefit Pension Plan Adjustments [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Prior service cost	[1]	(10)	(9)	(12)
Actuarial loss	[1]	(392)	(2,393)	(4,800)
Income Before Provision for Income Taxes	[1],[2]	(402)	(2,402)	(4,812)
Tax benefit	[1]	101	602	1,161
Income applicable to common stock	[1]	(301)	(1,800)	(3,651)
Income applicable to common stock	[1]	(301)	(1,800)	(3,651)
Cash Flow Hedge Adjustments [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income Before Provision for Income Taxes	[1]	10	9	9
Income applicable to common stock	[1]	10	9	9
Income applicable to common stock	[1]	10	9	9
Cash Flow Hedge Adjustments [Member] | Foreign exchange contracts [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of Sales	[1]	10	9	9
Accumulated Other Comprehensive Income (Loss) [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income applicable to common stock	[1]	(291)	(1,791)	(3,642)
Income applicable to common stock	[1]	$ (291)	$ (1,791)	$ (3,642)
[1] Amounts in parentheses denote expense to the Company’s Consolidated Statements of Income. This component of accumulated other comprehensive income is included in the computation of net periodic benefit cost (see Note 13, Postretirement Benefit Plans , of the notes to the Company’s consolidated financial statements for details regarding net periodic benefit costs for the Company’s U.S. and U.K. defined benefit plans).

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail)				12 Months Ended
	Sep. 23, 2022 USD ($)	Feb. 02, 2021 USD ($)	Jan. 29, 2021 USD ($) Site	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2023 USD ($)
Business Acquisition [Line Items]
Purchase price				$ 9,693,000	$ 184,473,000
Payment of working capital			$ 21,560,000
Payment of value added tax			3,000,000
Cash acquired on working capital			$ 5,900,000
Paid from cash on hand, assets acquired					3,503,000
Goodwill				95,922,000	97,187,000	$ 97,442,000
Polymer Segment [Member]
Business Acquisition [Line Items]
Goodwill				71,747,000	74,482,000	73,166,000
Surfactants Segment [Member]
Business Acquisition [Line Items]
Goodwill				$ 23,692,000	$ 22,222,000	$ 24,276,000
PerformanX Specialty Chemicals LLC [Member] | Surfactants Segment [Member] | 2022 Acquisitions [Member]
Business Acquisition [Line Items]
Asset purchase agreement date	Sep. 23, 2022
Purchase price	$ 9,693,000
Goodwill	1,792,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory	1,312,000
Payment of estimated working capital	579,000
PerformanX Specialty Chemicals LLC [Member] | Surfactants Segment [Member] | 2022 Acquisitions [Member] | Noncompete Agreements [Member]
Business Acquisition [Line Items]
Identifiable intangible assets	10,000
Intangible assets identified related to acquisition	10,000
PerformanX Specialty Chemicals LLC [Member] | Surfactants Segment [Member] | 2022 Acquisitions [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Identifiable intangible assets	3,250,000
Intangible assets identified related to acquisition	$ 3,250,000
PerformanX Specialty Chemicals LLC [Member] | Surfactants Segment [Member] | 2022 Acquisitions [Member] | Customer Relationships [Member] | Minimum [Member]
Business Acquisition [Line Items]
Weighted average amortization periods of identifiable intangibles assets	9 years
PerformanX Specialty Chemicals LLC [Member] | Surfactants Segment [Member] | 2022 Acquisitions [Member] | Customer Relationships [Member] | Maximum [Member]
Business Acquisition [Line Items]
Weighted average amortization periods of identifiable intangibles assets	11 years
PerformanX Specialty Chemicals LLC [Member] | Surfactants Segment [Member] | 2022 Acquisitions [Member] | Product Know-how [Member]
Business Acquisition [Line Items]
Identifiable intangible assets	$ 2,750,000,000
Intangible assets identified related to acquisition	$ 2,750,000,000
PerformanX Specialty Chemicals LLC [Member] | Surfactants Segment [Member] | 2022 Acquisitions [Member] | Product Know-how [Member] | Minimum [Member]
Business Acquisition [Line Items]
Weighted average amortization periods of identifiable intangibles assets	9 years
PerformanX Specialty Chemicals LLC [Member] | Surfactants Segment [Member] | 2022 Acquisitions [Member] | Product Know-how [Member] | Maximum [Member]
Business Acquisition [Line Items]
Weighted average amortization periods of identifiable intangibles assets	10 years
INVISTA Aromatic Polyester Polyol Business Acquisition [Member] | Polymer Segment [Member] | 2021 Acquisitions [Member]
Business Acquisition [Line Items]
Asset purchase agreement date			Jan. 29, 2021
Number of manufacturing site | Site			2
Purchase price			$ 165,000,000
Goodwill			$ 64,800,000
Fermentation Plant Acquisition | 2021 Acquisitions [Member]
Business Acquisition [Line Items]
Paid from cash on hand, assets acquired		$ 3,500,000

Acquisitions - Summary of Purch

Acquisitions - Summary of Purchase Price Allocation for Major Components of Acquisition (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 29, 2021
Assets:
Goodwill	$ 97,442	$ 95,922	$ 97,187
Polymer Segment [Member]
Assets:
Goodwill	$ 73,166	$ 71,747	$ 74,482
INVISTA Aromatic Polyester Polyol Business Acquisition [Member] | 2021 Acquisitions [Member] | Polymer Segment [Member]
Assets:
Property, plant and equipment				$ 54,200
Identifiable intangibles assets				46,000
Goodwill				64,800
Total assets acquired				$ 165,000

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2020	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Contract assets	$ 0
Contract liabilities	688,000
Contract liabilities revenue recognized	1,846,000	$ 10,709,000
Pre-existing Contract Liabilities [Member]
Disaggregation of Revenue [Line Items]
Contract liabilities			$ 739,000
Long-Term [Member]
Disaggregation of Revenue [Line Items]
Contract liabilities revenue recognized	6,647,000
Short-Term [Member]
Disaggregation of Revenue [Line Items]
Contract liabilities revenue recognized	$ 2,216,000

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Summary of Geographic Disaggregation of Net Sales (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation Of Revenue [Line Items]
Net sales	[1]	$ 2,325,768	$ 2,773,270	$ 2,345,966
Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales		1,602,819	1,882,745	1,562,795
Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales		642,471	789,080	713,440
Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales		80,478	101,445	69,731
North America [Member]
Disaggregation Of Revenue [Line Items]
Net sales		1,354,999	1,620,735	1,328,312
North America [Member] | Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales		949,218	1,099,616	904,469
North America [Member] | Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales		338,979	437,312	364,382
North America [Member] | Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales		66,802	83,807	59,461
Europe [Member]
Disaggregation Of Revenue [Line Items]
Net sales		561,915	673,210	600,024
Europe [Member] | Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales		289,010	349,651	288,735
Europe [Member] | Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales		259,491	307,441	302,137
Europe [Member] | Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales		13,414	16,118	9,152
Latin America [Member]
Disaggregation Of Revenue [Line Items]
Net sales		306,244	369,948	304,542
Latin America [Member] | Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales		304,870	363,799	299,601
Latin America [Member] | Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales		1,112	4,629	3,823
Latin America [Member] | Specialty Products [Member]
Disaggregation Of Revenue [Line Items]
Net sales		262	1,520	1,118
Asia [Member]
Disaggregation Of Revenue [Line Items]
Net sales		102,610	109,377	113,088
Asia [Member] | Surfactants [Member]
Disaggregation Of Revenue [Line Items]
Net sales		59,721	69,679	69,990
Asia [Member] | Polymers [Member]
Disaggregation Of Revenue [Line Items]
Net sales		$ 42,889	$ 39,698	$ 43,098
[1] Includes net property, plant and equipment, goodwill and other intangible assets.

Business Restructuring, Asset_2

Business Restructuring, Assets Impairment and Asset Disposition - Additional Information (Detail)	3 Months Ended			12 Months Ended
	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2023 USD ($) Employees	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Discontinued Operations, Disposed of by Sale
Restructuring Cost And Reserve [Line Items]
Gain on sale of asset			$ (2,720,000)
2023 Restructuring [Member]
Restructuring Cost And Reserve [Line Items]
Business restructuring	$ 2,883,000	$ 5,530,000
Assets impairment charges	$ 3,164,000
2016 Restructuring [Member] | Longford Mills [Member] | Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Business restructuring				$ 9,949,000
Number positions eliminated | Employees				30
2016 Restructuring [Member] | Decommissioning Costs [Member] | Longford Mills [Member] | Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Business restructuring				$ 391,000	$ 308,000	$ 633,000
2016 Restructuring [Member] | Termination Benefits [Member] | Longford Mills [Member] | Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Business restructuring				1,644,000
2016 Restructuring [Member] | Other Expense [Member] | Longford Mills [Member] | Surfactants [Member]
Restructuring Cost And Reserve [Line Items]
Business restructuring				$ 8,305,000

Noncash Investing and Financi_2

Noncash Investing and Financing Activities - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Supplemental Cash Flow Elements [Line Items]
Noncash investing activities, payables incurred for property, plant and equipment expenditures, unpaid	$ 16,222,000	$ 55,480,000	$ 36,588,000
Common Stock [Member] | Stock Award Plan [Member]
Supplemental Cash Flow Elements [Line Items]
Noncash financing activities shares issued	103,745	58,441	60,132
Noncash financing activities issued value	$ 10,916,000	$ 6,095,000	$ 7,286,000