Innospec (IOSP) 10-Q 6 Nov 24 2024 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2024	Oct. 31, 2024
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Document Quarterly Report	true
Document Transition Report	false
Current Fiscal Year End Date	--12-31
Document Period End Date	Sep. 30, 2024
Entity File Number	1-13879
Entity Registrant Name	INNOSPEC INC.
Entity Central Index Key	0001054905
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	98-0181725
City Area Code	303
Entity Address, Postal Zip Code	80112
Local Phone Number	792 5554
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common stock
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		24,941,596
Entity Address, Address Line One	8310 South Valley Highway
Entity Address, Address Line Two	Suite 350
Entity Address, City or Town	Englewood
Entity Address, State or Province	CO
Trading Symbol	IOSP
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
Net sales	$ 443.4	$ 464.1	$ 1,378.6	$ 1,454.1
Cost of goods sold	(319.3)	(326.9)	(971.9)	(1,018.7)
Gross profit	124.1	137.2	406.7	435.4
Operating expenses:
Selling, general and administrative	(66.8)	(83.7)	(232.9)	(285.5)
Research and development	(11.1)	(11.6)	(35.1)	(32.8)
Adjustment to fair value of contingent consideration	(0.7)	0	(2.1)	0
Profit on disposal of property, plant and equipment	0.1	0	0.2	0
Total operating expenses	(78.5)	(95.3)	(269.9)	(318.3)
Operating income	45.6	41.9	136.8	117.1
Other income/(expense), net	(3.5)	4.8	0.1	11.2
Interest income, net	2.7	0.8	6.9	0.8
Income before income tax expense	44.8	47.5	143.8	129.1
Income tax expense	(11.4)	(8.3)	(37.8)	(27.8)
Net income	$ 33.4	$ 39.2	$ 106	$ 101.3
Earnings per share:
Basic	$ 1.34	$ 1.58	$ 4.25	$ 4.08
Diluted	$ 1.33	$ 1.57	$ 4.22	$ 4.05
Weighted average shares outstanding (in thousands):
Basic	24,941	24,866	24,926	24,845
Diluted	25,101	25,006	25,103	25,000

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 33.4	$ 39.2	$ 106	$ 101.3
Changes in cumulative translation adjustment	14.4	(8.4)	0.4	(1.6)
Amortization of prior service cost	0.1	0.2	0.4	0.4
Amortization of actuarial net gains	(0.1)	(0.6)	(0.2)	(1.6)
Other comprehensive income/(loss), before tax	14.4	(8.8)	0.6	(2.8)
Tax related to cumulative translation adjustment	0.9	0.5	2.3	(0.2)
Tax related to other movements	0	0.1	(0.1)	0.3
Income tax income/(expense) related to other comprehensive income	0.9	0.6	2.2	0.1
Total comprehensive income	$ 48.7	$ 31	$ 108.8	$ 98.6

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 303.8	$ 203.7
Trade and other accounts receivable (less allowances of $9.5 million and $10.3 million respectively)	327.6	359.8
Inventories (less allowances of $34.9 million and $28.1 million respectively):
Finished goods	221.1	215.7
Raw materials	98.2	84.4
Total inventories	319.3	300.1
Prepaid expenses	9.2	18.7
Prepaid income taxes	5.1	2.8
Other current assets	0.6	0.6
Total current assets	965.6	885.7
Net property, plant and equipment	278.2	268.3
Operating lease right-of-use assets	45.5	45.1
Goodwill	392.3	399.3
Other intangible assets	63.6	57.3
Deferred tax assets	10.5	10.4
Pension asset	38.1	35.1
Other non-current assets	3.9	6.2
Total assets	1,797.7	1,707.4
Current liabilities:
Accounts payable	169	163.6
Accrued liabilities	170	185.9
Current portion of operating lease liabilities	14	13.6
Current portion of plant closure provisions	4.6	4.6
Current portion of accrued income taxes	15.5	2.6
Current portion of unrecognized tax benefits	0	1.2
Total current liabilities	373.1	371.5
Operating lease liabilities, net of current portion	31.7	31.6
Plant closure provisions, net of current portion	58.7	57
Accrued income taxes, net of current portion	0	11.6
Unrecognized tax benefits	11	13.6
Deferred tax liabilities	35.8	33.5
Pension liabilities and post-employment benefits	13.3	13.3
Acquisition-related contingent consideration	21.5	23.4
Other non-current liabilities	5	2.3
Total liabilities	550.1	557.8
Equity:
Common stock, $0.01 par value, authorized 40,000,000 shares, issued 29,554,500 shares	0.3	0.3
Additional paid-in capital	366.6	361
Treasury stock (4,612,904 and 4,686,511 shares at cost, respectively)	(93.4)	(94.3)
Retained earnings	1,115.2	1,028.2
Accumulated other comprehensive loss	(145.3)	(148.1)
Total Innospec stockholders' equity	1,243.4	1,147.1
Non-controlling interest	4.2	2.5
Total equity	1,247.6	1,149.6
Total liabilities and equity	$ 1,797.7	$ 1,707.4

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Statement of Financial Position [Abstract]
Allowances for doubtful accounts	$ 9.5	$ 10.3
Inventory allowances	$ 34.9	$ 28.1
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	29,554,500	29,554,500
Treasury stock, shares	4,612,904	4,686,511

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash Flows from Operating Activities
Net income	$ 106	$ 101.3
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	32.6	29.1
Adjustment to fair value of contingent consideration	2.1	0
Deferred taxes	0.6	0.5
Profit on disposal of property, plant and equipment	(0.2)	0
Non-cash movements on defined benefit pension plans	(2.5)	(2.5)
Stock option compensation	6.4	5.9
Changes in assets and liabilities, net of effects of acquired and divested companies:
Trade and other accounts receivable	33.5	29.5
Inventories	(17.6)	42
Prepaid expenses	9.6	6.5
Accounts payable and accrued liabilities	(13.6)	(57.2)
Plant closure provisions	0	(1.2)
Income taxes	1.5	(20.2)
Unrecognized tax benefits	(3.8)	0.7
Other assets and liabilities	4.2	0.5
Net cash provided by operating activities	158.8	134.9
Cash Flows from Investing Activities
Capital expenditures	(29.3)	(45.2)
Internally developed software	(12.2)	(10.8)
Business combinations, net of cash acquired	(0.2)	0
Proceeds on disposal of property, plant and equipment	0.3	0
Net cash used in investing activities	(41.4)	(56)
Cash Flows from Financing Activities
Non-controlling interest	1.7	0.3
Refinancing costs	(0.3)	(1.4)
Dividend paid	(19)	(17.2)
Issue of treasury stock	0.8	0.7
Repurchase of common stock	(0.7)	(1)
Net cash used in financing activities	(17.5)	(18.6)
Effect of foreign currency exchange rate changes on cash	0.2	(0.2)
Net change in cash and cash equivalents	100.1	60.1
Cash and cash equivalents at beginning of period	203.7	147.1
Cash and cash equivalents at end of period	$ 303.8	$ 207.2

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Equity (Unaudited) - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Non-Controlling Interest [Member]
Beginning Balance at Dec. 31, 2022	$ 1,040.4	$ 0.3	$ 354.1	$ (95.4)	$ 924.2	$ (145.2)	$ 2.4
Net income	101.3				101.3
Dividend paid	(17.2)				(17.2)
Changes in cumulative translation adjustment, net of tax	(1.8)					(1.8)
Share of net income	0.3						0.3
Treasury stock reissued	1.1		(1.1)	2.2
Treasury stock repurchased	(1)			(1)
Stock option compensation	5.9		5.9
Amortization of prior service cost, net of tax	0.3					0.3
Amortization of actuarial net losses, net of tax	(1.2)					(1.2)
Ending Balance at Sep. 30, 2023	1,128.1	0.3	358.9	(94.2)	1,008.3	(147.9)	2.7
Beginning Balance at Jun. 30, 2023	1,094.8	0.3	356.7	(94.2)	969.1	(139.7)	2.6
Net income	39.2				39.2
Changes in cumulative translation adjustment, net of tax	(7.9)					(7.9)
Non-controlling interest	0.1						0.1
Treasury stock reissued	0.3		0.2	0.1
Treasury stock repurchased	(0.1)			(0.1)
Stock option compensation	2		2
Amortization of prior service cost, net of tax	0.1					0.1
Amortization of actuarial net losses, net of tax	(0.4)					(0.4)
Ending Balance at Sep. 30, 2023	1,128.1	0.3	358.9	(94.2)	1,008.3	(147.9)	2.7
Beginning Balance at Dec. 31, 2023	1,149.6	0.3	361	(94.3)	1,028.2	(148.1)	2.5
Net income	106				106
Dividend paid	(19)				(19)
Changes in cumulative translation adjustment, net of tax	2.7					2.7
Share of net income	1.7						1.7
Treasury stock reissued	0.8		(0.8)	1.6
Treasury stock repurchased	(0.7)			(0.7)
Stock option compensation	6.4		6.4
Amortization of prior service cost, net of tax	0.3					0.3
Amortization of actuarial net losses, net of tax	(0.2)					(0.2)
Ending Balance at Sep. 30, 2024	1,247.6	0.3	366.6	(93.4)	1,115.2	(145.3)	4.2
Beginning Balance at Jun. 30, 2024	1,195.9	0.3	364.5	(93.4)	1,081.8	(160.6)	3.3
Net income	33.4				33.4
Changes in cumulative translation adjustment, net of tax	15.3					15.3
Share of net income	0.9						0.9
Treasury stock reissued	(0.1)		(0.1)
Treasury stock repurchased	0
Stock option compensation	2.2		2.2
Amortization of prior service cost, net of tax	0
Ending Balance at Sep. 30, 2024	$ 1,247.6	$ 0.3	$ 366.6	$ (93.4)	$ 1,115.2	$ (145.3)	$ 4.2

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Equity (Parenthetical) (Unaudited) - $ / shares	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Statement of Stockholders' Equity [Abstract]
Dividend paid, per share	$ 0.76	$ 0.69

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	NOTE 1 – BASIS OF PRESENTATION The accompanying unaudited interim condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X under the Securities Exchange Act of 1934. Accordingly, they do not include all the information and notes necessary for a comprehensive presentation of financial position, results of operations and cash flows. It is our opinion, however, that all adjustments (consisting of normal, recurring adjustments, unless otherwise disclosed) have been made which are necessary for the condensed consolidated financial statements to be fairly stated. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023, filed on February 14, 2024 (the “2023 Form 10-K”). The results for the interim period covered by this report are not necessarily indicative of the results to be expected for the full year. When we use the terms “Innospec,” “the Corporation,” “the Company,” “Registrant,” “the Group,” “we,” “us” and “our,” we are referring to Innospec Inc. and its consolidated subsidiaries unless otherwise indicated or the context otherwise requires.

Segment Reporting

Segment Reporting	9 Months Ended
	Sep. 30, 2024
Segment Reporting [Abstract]
Segment Reporting	NOTE 2 – SEGMENT REPORTING The Company reports its financial performance based on three reportable segments, which are Performance Chemicals, Fuel Specialties and Oilfield Services. The Company evaluates the performance of its segments based on operating income. The following table analyzes sales and other financial information by the Company’s reportable segments: Three Months Ended Nine Months Ended (in millions) 2024 2023 2024 2023 Net Sales: Personal Care $ 98.6 $ 97.0 $ 291.1 $ 263.8 Home Care 26.5 22.3 77.2 65.7 Other 38.5 25.9 116.2 94.9 Performance Chemicals 163.6 145.2 484.5 424.4 Refinery and Performance 120.9 126.0 375.1 394.6 Other 44.9 43.3 134.2 119.2 Fuel Specialties 165.8 169.3 509.3 513.8 Oilfield Services 114.0 149.6 384.8 515.9 $ 443.4 $ 464.1 $ 1,378.6 $ 1,454.1 Operating income/(loss): Performance Chemicals $ 20.0 $ 16.9 $ 62.3 $ 36.5 Fuel Specialties 30.9 27.6 94.7 77.1 Oilfield Services 7.1 16.4 31.3 60.3 Corporate costs ( 11.8 ) ( 19.0 ) ( 49.6 ) ( 56.8 ) Adjustment to fair value of contingent consideration ( 0.7 ) — ( 2.1 ) — Profit on disposal of property, plant and equipment 0.1 — 0.2 — Total operating income $ 45.6 $ 41.9 $ 136.8 $ 117.1

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Earnings per Share	NOTE 3 – EARNINGS PER SHARE Basic earnings per share is based on the weighted average number of common shares outstanding during the period. Diluted earnings per share includes the effect of options that are dilutive and outstanding during the period under the treasury stock method. Per share amounts are computed as follows: Three Months Ended Nine Months Ended 2024 2023 2024 2023 Numerator (in millions): Net income available to common stockholders $ 33.4 $ 39.2 $ 106.0 $ 101.3 Denominator (in thousands): Weighted average common shares outstanding 24,941 24,866 24,926 24,845 Dilutive effect of stock options and awards 160 140 177 155 Denominator for diluted earnings per share 25,101 25,006 25,103 25,000 Net income per share, basic: $ 1.34 $ 1.58 $ 4.25 $ 4.08 Net income per share, diluted: $ 1.33 $ 1.57 $ 4.22 $ 4.05 In the three and nine months ended September 30, 2024, the average number of anti-dilutive options excluded from the calculation of diluted earnings per share were 10,436 and 10,436 , respectively (three and nine months ended September 30, 2023 – 21,950 and 29,293 , respectively).

Goodwill

Goodwill	9 Months Ended
	Sep. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	NOTE 4 – GOODWILL The following table summarizes the goodwill movements in the year: (in millions) Gross Cost Opening balance at January 1, 2024 $ 399.3 Adjustments ( 3.4 ) Exchange effect ( 3.6 ) Closing balance at September 30, 2024 $ 392.3 In relation to the acquisition of QGP Química Geral S.A. (“QGP”) in December 2023, the fair value of the acquired net assets was revised in the second quarter of 2024. As a result of the remeasurement period adjustments, there was an increase of $ 3.4 million in the fair value of the net assets acquired, with a corresponding decrease to the acquired goodwill. The measurement periods for the valuation of assets acquired and liabilities assumed ends as soon as information on the facts and circumstances that existed as of the acquisition dates becomes available but does not exceed twelve months. We completed our alignment of the accounting policies and fair value adjustments in the second quarter and are not expecting further changes at this time. The exchange effect for the nine months ended September 30, 2024 was $ 3.6 million relating to our Performance Chemicals segment.

Other Intangible Assets

Other Intangible Assets	9 Months Ended
	Sep. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Other Intangible Assets	NOTE 5 – OTHER INTANGIBLE ASSETS The following table analyzes other intangible assets movements in the year: (in millions) 2024 Gross cost at January 1 $ 315.1 Additions 15.6 Exchange effect 1.6 Gross cost at September 30 332.3 Accumulated amortization at January 1 ( 257.8 ) Amortization expense ( 9.6 ) Exchange effect ( 1.3 ) Accumulated amortization at September 30 ( 268.7 ) Net book amount at September 30 $ 63.6 The amortization expense for the nine months ended September 30, 2024 was $ 9.6 million (nine months ended September 30, 2023 – $ 8.0 million). In relation to the acquisition of QGP in December 2023, management finalized the valuation of customer lists which has increased the intangible asset capitalized by $ 3.5 million in the second quarter of 2024. Management also revised the expected useful life of the customer lists from 10 years to 7 years. In 2024, we have capitalized $ 12.1 million in relation to our internally developed software for a new Enterprise Resource Planning (“ERP”) system covering our EMEA and ASPAC regions. The expenses capitalized include the acquisition costs for the software as well as the external and internal costs of the development.

Pension and Post-Employment Ben

Pension and Post-Employment Benefits	9 Months Ended
	Sep. 30, 2024
Retirement Benefits [Abstract]
Pension and Post-Employment Benefits	NOTE 6 – PENSION AND POST EMPLOYMENT BENEFITS The Company maintains a defined benefit pension plan covering certain current and former employees in the United Kingdom (the “UK Plan”). The UK Plan is closed to future service accrual and has a large number of deferred and current pensioners. The assets of the UK Plan are predominantly insurance policies, operating as investment assets, covering all liabilities. This reduces the UK Plan’s potential reliance on the Company for future cash funding requirements. On September 9, 2024, the Company entered into a Deed of Alteration and Agreement (the "Pension Deed") with the trustees of the UK Plan, covering a number of aspects including the Company notice to terminate the UK Plan and commencement of winding up and move to buy-out. The Company currently expects the trigger for final settlement accounting of the UK Plan to occur during the fourth quarter of 2024. As a consequence of the Pension Deed, the trustees have repaid $ 8.4 million of historical costs which the Company had incurred in relation to the UK Plan. The recovered costs have been included within the service credit in the table below. The Company also maintains an unfunded defined benefit pension plan covering certain current and former employees in Germany (the “German plan”). The German plan is closed to new entrants and has no assets. The net periodic benefit of these plans is shown in the following table: Three Months Ended Nine Months Ended (in millions) 2024 2023 2024 2023 Service credit/(cost) $ 7.6 $ ( 0.9 ) $ 5.9 $ ( 2.7 ) Interest cost on projected benefit obligation ( 4.8 ) ( 5.1 ) ( 14.1 ) ( 15.0 ) Expected return on plan assets 6.5 6.5 19.3 19.0 Amortization of prior service cost ( 0.1 ) ( 0.2 ) ( 0.4 ) ( 0.4 ) Amortization of actuarial net gains 0.1 0.6 0.2 1.6 Net periodic benefit $ 9.3 $ 0.9 $ 10.9 $ 2.5 The service cost has been recognized in selling, general and administrative expenses. All other items have been recognized within other income and expense. The amortization of prior service cost and actuarial net gains are a reclassification out of accumulated other comprehensive loss into other income and expense. In addition, we have obligations for post-employment benefits in some of our other European businesses. As at September 30, 2024, we have recorded a liability of $ 4.2 million (December 31, 2023 – $ 4.2 million).

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 7 – INCOME TAXES A roll-forward of unrecognized tax benefits and associated accrued interest and penalties is as follows: (in millions) Unrecognized Interest and Total Opening balance at January 1, 2024 $ 10.5 $ 4.3 $ 14.8 Increase for tax positions of prior periods — 0.8 0.8 Decrease for settlement of tax positions ( 3.3 ) ( 1.3 ) ( 4.6 ) Closing balance at September 30, 2024 7.2 3.8 11.0 Current — — — Non-current $ 7.2 $ 3.8 $ 11.0 All of the $ 11.0 million of unrecognized tax benefits, interest and penalties would impact our effective tax rate if recognized. In 2021 a non-U.S. subsidiary, Innospec Limited, entered into a review by the U.K. tax authorities under the U.K.’s Profit Diversion Compliance Facility (“PDCF”) in relation to the period 2017 to 2020 inclusive . The Company has determined that additional tax, interest and penalties totaling $ 1.2 million will arise as a consequence of the review. During the quarter ended September 30, 2024, the Company and the U.K. tax authorities reached agreement on this position, and the liability was settled. The liability which was agreed on ultimate settlement was consistent with the amount recorded as a liability, and this item has been released from unrecognized tax benefits and recognized in income taxes. In 2018 the Company recorded an unrecognized tax benefit in relation to a potential adjustment that could arise as a consequence of the Tax Cuts and Jobs Act of 2017 (“Tax Act”), but for which retrospective adjustment to the filed 2017 U.S. federal income tax returns was not permissible. The Company has determined that additional tax, interest and penalties totaling $ 11.0 million may arise in relation to this item. This includes an increase in interest accrued of $ 0.8 million in the nine months to September 30, 2024. The Company believes that it is reasonably possible that there will be a decrease of $ 11.0 million unrecognized tax benefits during the fourth quarter of 2024 in relation to this item due to a lapse of the statute of limitations. A non-U.S. subsidiary, Innospec Performance Chemicals Italia Srl, has been subject to an ongoing tax audit in relation to the period 2011 to 2014 inclusive. The Company had determined that additional tax, interest and penalties totaling $ 3.4 million will arise as a consequence of the tax audit. As any additional tax arising as a consequence of the tax audit is to be reimbursed by the previous owner under the terms of the sale and purchase agreement, an indemnification asset of the same amount is recorded in the financial statements to reflect this arrangement. During the quarter ended June 30, 2024, the Company submitted documentation to the tax authorities confirming its acceptance of the previously disputed position, and due to imminent settlement, this item was released from unrecognized tax benefits and recognized in accrued income taxes in that quarter. As of September 30, 2024, the Company and its U.S. subsidiaries remain open to examination by the IRS for certain elements of 2017 year and for years 2020 onwards under the statute of limitations . The Company’s subsidiaries in foreign tax jurisdictions are open to examination including Brazil (2019 onwards), Germany (2019 onwards), and the U.K. (2022 onwards).

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Long-Term Debt	NOTE 8 – LONG-TERM DEBT As at September 30, 2024, and December 31, 2023, the Company had no t drawn down on its revolving credit facility. During the first nine months of 2024 and 2023, the Company did no t draw down or repay any borrowing on its revolving credit facility. The Company continues to have available a $ 250.0 million multicurrency revolving credit facility (the "Facility") until May 30, 2027 . The Facility contains an accordion feature whereby the Company may elect to increase the total available borrowings by an aggregate amount of up to $ 125.0 million. Effective as of May 20, 2024, the termination date of the Facility was extended from May 30, 2027 to May 31, 2028 in accordance with the terms of the Company’s multicurrency revolving facility agreement (the “Facility Agreement”). No other terms of the Facility Agreement or the Facility were modified. The Company paid a customary extension fee in connection with the extension of the Facility as contemplated by the Facility Agreement. As at September 30, 2024, the deferred finance costs of $ 1.2 million (December 31, 2023 - $ 1.2 million) related to the arrangement of the credit facility, are included within other current and non-current assets at the balance sheet dates.

Plant Closure Provisions

Plant Closure Provisions	9 Months Ended
	Sep. 30, 2024
Restructuring and Related Activities [Abstract]
Plant Closure Provisions	NOTE 9 – PLANT CLOSURE PROVISIONS The Company has continuing plans to remediate manufacturing facilities at sites around the world as and when those operations are expected to cease, or we are required to decommission the sites according to local laws and regulations. The liability for estimated plant closure costs includes costs for environmental remediation liabilities and asset retirement obligations. The principal site giving rise to asset retirement obligations is the manufacturing site at Ellesmere Port in the United Kingdom. There are also asset retirement obligations and environmental remediation liabilities on a much smaller scale in respect of other manufacturing sites. Movements in the provisions are summarized as follows: (in millions) 2024 Total at January 1 $ 61.6 Charge for the period 2.6 Utilized in the period ( 2.6 ) Exchange effect 1.7 Total at September 30 63.3 Due within one year ( 4.6 ) Due after one year $ 58.7 The charge for the nine months ended September 30, 2024, was $ 2.6 million (nine months ended September 30, 2023 – $ 2.7 million). The current year charge represents the accounting accretion only, with no changes for the expected cost and scope of future remediation activities. Amounts due within one year refer to provisions where expenditure is expected to arise within one year of the balance sheet date.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	NOTE 10 – FAIR VALUE MEASUREMENTS The following table presents the carrying amount and fair values of the Company’s financial assets and liabilities measured on a recurring basis: September 30, 2024 December 31, 2023 (in millions) Carrying Fair Carrying Fair Assets Derivatives (Level 1 measurement): Other current and non-current assets: Emissions Trading Scheme credits 4.2 4.2 4.8 4.8 Foreign currency forward exchange contracts 0.3 0.3 — — Liabilities Derivatives (Level 1 measurement): Other current and non-current liabilities: Foreign currency forward exchange contracts — — 1.0 1.0 Non-financial liabilities (Level 3 measurement): Acquisition-related contingent consideration 21.5 21.5 23.4 23.4 The following methods and assumptions were used to estimate the fair values: Emissions Trading Scheme credits: The fair value is determined by the open market pricing at the end of the reporting period. Foreign currency forward exchange contracts: The fair value of derivatives relating to foreign currency forward exchange contracts are derived from current settlement prices and comparable contracts using current assumptions. Foreign currency forward exchange contracts primarily relate to contracts entered into to hedge future known transactions or hedge balance sheet net cash positions. The movements in the carrying amounts and fair values of these contracts are largely due to changes in exchange rates against the U.S. dollar. Acquisition-related contingent consideration: Contingent consideration payable in cash is discounted to its fair value at each balance sheet date. Where contingent consideration is dependent upon pre-determined financial targets, an estimate of the fair value of the likely consideration payable is made at each balance sheet date. The contingent consideration payable has been calculated based on the latest forecast.

Derivative Instruments and Risk

Derivative Instruments and Risk Management	9 Months Ended
	Sep. 30, 2024
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Risk Management	NOTE 11 – DERIVATIVE INSTRUMENTS AND RISK MANAGEMENT The Company enters into various foreign currency forward exchange contracts to minimize currency exchange rate exposure from expected future cash flows. As at September 30, 2024, the contracts have maturity dates of up to twelve months at the date of inception. These foreign currency forward exchange contracts have not been designated as hedging instruments, and their impact on the income statement for the first nine months of 2024 was a loss of $ 1.1 million (first nine months of 2023 – a loss of $ 1.2 million). The gain or loss has been recorded in other income or expense.

Contingencies

Contingencies	9 Months Ended
	Sep. 30, 2024
Commitments and Contingencies Disclosure [Abstract]
Contingencies	NOTE 12 – CONTINGENCIES Le g al matters We are involved from time to time in claims and legal proceedings that result from, and are incidental to, the conduct of our business including business and commercial litigation, and employee and product liability claims. As reported in the 2023 Form 10-K, we have incurred financial losses and lodged a civil and criminal legal claim related to a misappropriation of inventory in Brazil. As at the time of filing, there have been no significant developments to report in relation to the claims being made. Consistent with prior quarters, a corresponding asset for the potential legal or insurance recoveries has not been recorded for the resulting financial losses arising from this matter. In addition, unrelated to the Brazil matter, in the unlikely event there are an unexpectedly large number of individual claims or proceedings with an adverse resolution, this could in the aggregate have a material adverse effect on the results of operations for a particular year or quarter. Guarantees The Company and certain of the Company’s consolidated subsidiaries are contingently liable for certain obligations of affiliated companies primarily in the form of guarantees of debt and performance under contracts entered into as a normal business practice. This includes guarantees of non-U.S. excise taxes and customs duties. As at September 30, 2024, such guarantees which are not recognized as liabilities in the condensed consolidated financial statements amounted to $ 7.1 million (December 31, 2023 - $ 6.2 million). The remaining terms of the fixed maturity guarantees are up to 8 years, with some further guarantees having no fixed expiry date. Under the terms of the guarantee arrangements, generally the Company would be required to perform the obligations should the affiliated company fail to fulfill its obligations under the arrangements. In some cases, the guarantee arrangements have recourse provisions that would enable the Company to recover any payments made under the terms of the guarantees from securities held of the guaranteed parties’ assets. The Company and its affiliates have numerous long-term sales and purchase commitments in their various business activities, which are expected to be fulfilled with no adverse consequences material to the Company.

Stock-Based Compensation Plans

Stock-Based Compensation Plans	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation Plans	NOTE 13 – STOCK-BASED COMPENSATION PLANS The compensation cost recorded for stock options for the three months ended September 30, 2024 and 2023 was $ 2.2 million and $ 2.0 million, respectively. The compensation cost recorded for stock equivalent units for the three months ended September 30, 2024 and 2023 was $ 0.7 million and $ 2.0 million, respectively. The compensation cost recorded for stock options for the first nine months of 2024 and 2023 was $ 6.4 million and $5 .9 million, respectively. The compensation cost recorded for stock equivalent units for the first nine months of 2024 and 2023 was $ 4.8 million and $ 7.1 million, respectively. The following table summarizes the transactions of the Company’s share-based compensation plans for the nine months ended September 30, 2024. Number of Weighted Nonvested at December 31, 2023 652,891 $ 75.2 Granted 139,867 $ 130.3 Vested ( 184,170 ) $ 86.7 Forfeited ( 15,539 ) $ 82.2 Nonvested at September 30, 2024 593,049 $ 84.4 For the awards granted with market conditions, a Monte Carlo model has been used to calculate the grant-date fair value. For all other awards granted, a fair market value methodology has been used to calculate the grant-date fair value. The awards granted with market conditions include a performance measure for Innospec's total shareholder return as compared to a peer group of companies. This measure can result in a maximum 130 % vesting for the number of stock options granted. The maximum potential vesting has been reflected in the grant-date fair value calculation, but not reflected for the number of awards granted, as shown in the table above. All other awards granted in the quarter have similar vesting conditions to those granted in the previous periods. As of September 30, 2024, there was $ 23.5 million of total unrecognized compensation cost related to nonvested share-based compensation arrangements. That cost is expected to be recognized over a weighted-average period of 1.9 years.

Reclassifications out of Accumu

Reclassifications out of Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Reclassifications out of Accumulated Other Comprehensive Loss	NOTE 14 – RECLASSIFICATIONS OUT OF ACCUMULATED OTHER COMPREHENSIVE LOSS Reclassifications out of accumulated other comprehensive loss (“AOCL”) for the first nine months of 2024 were: (in millions) Amount Affected Line Item in the Defined benefit pension plan items: Amortization of prior service cost $ 0.4 See (1) below Amortization of actuarial net gains ( 0.2 ) See (1) below 0.2 Total before tax ( 0.1 ) Income tax expense Total reclassifications $ 0.1 Net of tax (1) These items are included in other income and expense. See Note 6 of the Notes to the Condensed Consolidated Financial Statements for additional information. Changes in AOCL for the first nine months of 2024, net of tax, were: (in millions) Defined Cumulative Total Balance at December 31, 2023 $ ( 77.2 ) $ ( 70.9 ) $ ( 148.1 ) Other comprehensive income/(loss) before reclassifications — 2.7 2.7 Amounts reclassified from AOCL 0.1 — 0.1 Total other comprehensive income/(loss) 0.1 2.7 2.8 Balance at September 30, 2024 $ ( 77.1 ) $ ( 68.2 ) $ ( 145.3 ) Reclassifications out of AOCL for the first nine months of 2023 were: (in millions) Amount Affected Line Item in the Defined benefit pension plan items: Amortization of prior service cost $ 0.4 See (1) below Amortization of actuarial net gains ( 1.6 ) See (1) below ( 1.2 ) Total before tax 0.3 Income tax expense Total reclassifications $ ( 0.9 ) Net of tax (1) These items are included in other income and expense. See Note 6 of the Notes to the Condensed Consolidated Financial Statements for additional information. Changes in AOCL for the first nine months of 2023, net of tax, were: (in millions) Defined Cumulative Total Balance at December 31, 2022 $ ( 58.4 ) $ ( 86.8 ) $ ( 145.2 ) Other comprehensive income/(loss) before reclassifications — ( 1.8 ) ( 1.8 ) Amounts reclassified from AOCL ( 0.9 ) — ( 0.9 ) Total other comprehensive income/(loss) ( 0.9 ) ( 1.8 ) ( 2.7 ) Balance at September 30, 2023 $ ( 59.3 ) $ ( 88.6 ) $ ( 147.9 )

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	9 Months Ended
	Sep. 30, 2024
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	NOTE 15 – RECENTLY ISSUED ACCOUNTING PRONOUNCEMENTS The Company has reviewed recently issued accounting pronouncements and concluded there were no matters relevant to the Company’s financial statements.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2024
Related Party Transactions [Abstract]
Related Party Transactions	NOTE 16 – RELATED PARTY TRANSACTIONS Mr. Patrick S. Williams has been an executive director of the Company since April 2009 and has been a non-executive director of AdvanSix Inc. ("AdvanSix"), a chemicals manufacturer, since February 2020. In the first nine months of 2024 the Company did no t purchase any product from AdvanSix (first nine months of 2023 – $ 0.3 million). As at September 30, 2024, the Company owed nil to AdvanSix (December 31, 2023 – nil ). Mr. Robert I. Paller was a non-executive director of the Company since November 1, 2009 until May 10, 2024, when he did not stand for re-election to the board. The Company has retained and continues to retain Smith, Gambrell & Russell, LLP (“SGR”), a law firm with which Mr. Paller holds a position. From January 1st until May 10th, 2024 the Company incurred fees from SGR of $ 0.2 million (first nine months of 2023 – $ 0.2 million). As at September 30, 2024, the Company owed nil to SGR (December 31, 2023 – nil ). Mr. David F. Landless has been a non-executive director of the Company since January 1, 2016 and is a non-executive director of Ausurus Group Limited which owns European Metal Recycling Limited (“EMR”). The Company has sold scrap metal to EMR in the first nine months of 2024 for a value of less than $ 0.1 million (first nine months of 2023 – $ 0.1 million). A tendering process is operated periodically to select the best buyer for the sale of scrap metal by the Company. As at September 30, 2024, EMR owed nil for scrap metal purchased from the Company (December 31, 2023 – nil ).

Segment Reporting (Tables)

Segment Reporting (Tables)	9 Months Ended
	Sep. 30, 2024
Segment Reporting [Abstract]
Segment Reporting	The Company evaluates the performance of its segments based on operating income. The following table analyzes sales and other financial information by the Company’s reportable segments: Three Months Ended Nine Months Ended (in millions) 2024 2023 2024 2023 Net Sales: Personal Care $ 98.6 $ 97.0 $ 291.1 $ 263.8 Home Care 26.5 22.3 77.2 65.7 Other 38.5 25.9 116.2 94.9 Performance Chemicals 163.6 145.2 484.5 424.4 Refinery and Performance 120.9 126.0 375.1 394.6 Other 44.9 43.3 134.2 119.2 Fuel Specialties 165.8 169.3 509.3 513.8 Oilfield Services 114.0 149.6 384.8 515.9 $ 443.4 $ 464.1 $ 1,378.6 $ 1,454.1 Operating income/(loss): Performance Chemicals $ 20.0 $ 16.9 $ 62.3 $ 36.5 Fuel Specialties 30.9 27.6 94.7 77.1 Oilfield Services 7.1 16.4 31.3 60.3 Corporate costs ( 11.8 ) ( 19.0 ) ( 49.6 ) ( 56.8 ) Adjustment to fair value of contingent consideration ( 0.7 ) — ( 2.1 ) — Profit on disposal of property, plant and equipment 0.1 — 0.2 — Total operating income $ 45.6 $ 41.9 $ 136.8 $ 117.1

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Summary of Earnings Per Share	Three Months Ended Nine Months Ended 2024 2023 2024 2023 Numerator (in millions): Net income available to common stockholders $ 33.4 $ 39.2 $ 106.0 $ 101.3 Denominator (in thousands): Weighted average common shares outstanding 24,941 24,866 24,926 24,845 Dilutive effect of stock options and awards 160 140 177 155 Denominator for diluted earnings per share 25,101 25,006 25,103 25,000 Net income per share, basic: $ 1.34 $ 1.58 $ 4.25 $ 4.08 Net income per share, diluted: $ 1.33 $ 1.57 $ 4.22 $ 4.05

Goodwill (Tables)

Goodwill (Tables)	9 Months Ended
	Sep. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Goodwill	The following table summarizes the goodwill movements in the year: (in millions) Gross Cost Opening balance at January 1, 2024 $ 399.3 Adjustments ( 3.4 ) Exchange effect ( 3.6 ) Closing balance at September 30, 2024 $ 392.3

Other Intangible Assets (Tables

Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Summary of Other Intangible Assets	The following table analyzes other intangible assets movements in the year: (in millions) 2024 Gross cost at January 1 $ 315.1 Additions 15.6 Exchange effect 1.6 Gross cost at September 30 332.3 Accumulated amortization at January 1 ( 257.8 ) Amortization expense ( 9.6 ) Exchange effect ( 1.3 ) Accumulated amortization at September 30 ( 268.7 ) Net book amount at September 30 $ 63.6

Pension and Post-Employment B_2

Pension and Post-Employment Benefits (Tables)	9 Months Ended
	Sep. 30, 2024
Plan Net Pension Credit	The net periodic benefit of these plans is shown in the following table: Three Months Ended Nine Months Ended (in millions) 2024 2023 2024 2023 Service credit/(cost) $ 7.6 $ ( 0.9 ) $ 5.9 $ ( 2.7 ) Interest cost on projected benefit obligation ( 4.8 ) ( 5.1 ) ( 14.1 ) ( 15.0 ) Expected return on plan assets 6.5 6.5 19.3 19.0 Amortization of prior service cost ( 0.1 ) ( 0.2 ) ( 0.4 ) ( 0.4 ) Amortization of actuarial net gains 0.1 0.6 0.2 1.6 Net periodic benefit $ 9.3 $ 0.9 $ 10.9 $ 2.5

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2024
Income Tax Disclosure [Abstract]
Roll-forward of Unrecognized Tax Benefits and Associated Accrued Interest and Penalties	A roll-forward of unrecognized tax benefits and associated accrued interest and penalties is as follows: (in millions) Unrecognized Interest and Total Opening balance at January 1, 2024 $ 10.5 $ 4.3 $ 14.8 Increase for tax positions of prior periods — 0.8 0.8 Decrease for settlement of tax positions ( 3.3 ) ( 1.3 ) ( 4.6 ) Closing balance at September 30, 2024 7.2 3.8 11.0 Current — — — Non-current $ 7.2 $ 3.8 $ 11.0

Plant Closure Provisions (Table

Plant Closure Provisions (Tables)	9 Months Ended
	Sep. 30, 2024
Restructuring and Related Activities [Abstract]
Movements in Plant Closure and Restructuring Provisions	Movements in the provisions are summarized as follows: (in millions) 2024 Total at January 1 $ 61.6 Charge for the period 2.6 Utilized in the period ( 2.6 ) Exchange effect 1.7 Total at September 30 63.3 Due within one year ( 4.6 ) Due after one year $ 58.7

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Carrying Amount and Fair Values of the Company's Assets and Liabilities Measured on a Recurring Basis	The following table presents the carrying amount and fair values of the Company’s financial assets and liabilities measured on a recurring basis: September 30, 2024 December 31, 2023 (in millions) Carrying Fair Carrying Fair Assets Derivatives (Level 1 measurement): Other current and non-current assets: Emissions Trading Scheme credits 4.2 4.2 4.8 4.8 Foreign currency forward exchange contracts 0.3 0.3 — — Liabilities Derivatives (Level 1 measurement): Other current and non-current liabilities: Foreign currency forward exchange contracts — — 1.0 1.0 Non-financial liabilities (Level 3 measurement): Acquisition-related contingent consideration 21.5 21.5 23.4 23.4

Stock-Based Compensation Plans

Stock-Based Compensation Plans (Tables)	9 Months Ended
	Sep. 30, 2024
Summary of Transactions of the Share Based Compensation Plans	The following table summarizes the transactions of the Company’s share-based compensation plans for the nine months ended September 30, 2024. Number of Weighted Nonvested at December 31, 2023 652,891 $ 75.2 Granted 139,867 $ 130.3 Vested ( 184,170 ) $ 86.7 Forfeited ( 15,539 ) $ 82.2 Nonvested at September 30, 2024 593,049 $ 84.4

Reclassifications out of Accu_2

Reclassifications out of Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Summary of Reclassifications Out of Accumulated Other Comprehensive Loss	Reclassifications out of accumulated other comprehensive loss (“AOCL”) for the first nine months of 2024 were: (in millions) Amount Affected Line Item in the Defined benefit pension plan items: Amortization of prior service cost $ 0.4 See (1) below Amortization of actuarial net gains ( 0.2 ) See (1) below 0.2 Total before tax ( 0.1 ) Income tax expense Total reclassifications $ 0.1 Net of tax (1) These items are included in other income and expense. See Note 6 of the Notes to the Condensed Consolidated Financial Statements for additional information. Reclassifications out of AOCL for the first nine months of 2023 were: (in millions) Amount Affected Line Item in the Defined benefit pension plan items: Amortization of prior service cost $ 0.4 See (1) below Amortization of actuarial net gains ( 1.6 ) See (1) below ( 1.2 ) Total before tax 0.3 Income tax expense Total reclassifications $ ( 0.9 ) Net of tax (1) These items are included in other income and expense. See Note 6 of the Notes to the Condensed Consolidated Financial Statements for additional information.
Changes in Accumulated Other Comprehensive Loss	Changes in AOCL for the first nine months of 2024, net of tax, were: (in millions) Defined Cumulative Total Balance at December 31, 2023 $ ( 77.2 ) $ ( 70.9 ) $ ( 148.1 ) Other comprehensive income/(loss) before reclassifications — 2.7 2.7 Amounts reclassified from AOCL 0.1 — 0.1 Total other comprehensive income/(loss) 0.1 2.7 2.8 Balance at September 30, 2024 $ ( 77.1 ) $ ( 68.2 ) $ ( 145.3 ) Changes in AOCL for the first nine months of 2023, net of tax, were: (in millions) Defined Cumulative Total Balance at December 31, 2022 $ ( 58.4 ) $ ( 86.8 ) $ ( 145.2 ) Other comprehensive income/(loss) before reclassifications — ( 1.8 ) ( 1.8 ) Amounts reclassified from AOCL ( 0.9 ) — ( 0.9 ) Total other comprehensive income/(loss) ( 0.9 ) ( 1.8 ) ( 2.7 ) Balance at September 30, 2023 $ ( 59.3 ) $ ( 88.6 ) $ ( 147.9 )

Segment Reporting - Segment Rep

Segment Reporting - Segment Reporting (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Net sales	$ 443.4	$ 464.1	$ 1,378.6	$ 1,454.1
Adjustment to fair value of contingent consideration	(0.7)	0	(2.1)	0
Profit on disposal of property, plant and equipment	0.1	0	0.2	0
Operating income/(loss)	45.6	41.9	136.8	117.1
Operating Segments [Member]
Segment Reporting Information [Line Items]
Adjustment to fair value of contingent consideration	(0.7)	0	(2.1)	0
Profit on disposal of property, plant and equipment	0.1	0	0.2	0
Operating Segments [Member] | Performance Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales	163.6	145.2	484.5	424.4
Operating income/(loss)	20	16.9	62.3	36.5
Operating Segments [Member] | Fuel Specialties [Member]
Segment Reporting Information [Line Items]
Net sales	165.8	169.3	509.3	513.8
Operating income/(loss)	30.9	27.6	94.7	77.1
Operating Segments [Member] | Oilfield Services [Member]
Segment Reporting Information [Line Items]
Net sales	114	149.6	384.8	515.9
Operating income/(loss)	7.1	16.4	31.3	60.3
Operating Segments [Member] | Personal Care [Member] | Performance Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales	98.6	97	291.1	263.8
Operating Segments [Member] | Home Care [Member] | Performance Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales	26.5	22.3	77.2	65.7
Operating Segments [Member] | Other [Member] | Performance Chemicals [Member]
Segment Reporting Information [Line Items]
Net sales	38.5	25.9	116.2	94.9
Operating Segments [Member] | Refinery and Performance [Member] | Fuel Specialties [Member]
Segment Reporting Information [Line Items]
Net sales	120.9	126	375.1	394.6
Operating Segments [Member] | Other [Member] | Fuel Specialties [Member]
Segment Reporting Information [Line Items]
Net sales	44.9	43.3	134.2	119.2
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Corporate costs	$ (11.8)	$ (19)	$ (49.6)	$ (56.8)

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Earnings Per Share [Abstract]
Average number of anti-dilutive options excluded from the calculation of diluted earnings per share	10,436	21,950	10,436	29,293

Earnings Per Share - Summary of

Earnings Per Share - Summary of Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator (in millions):
Net income available to common stockholders	$ 33.4	$ 39.2	$ 106	$ 101.3
Denominator (in thousands):
Weighted average common shares outstanding	24,941	24,866	24,926	24,845
Dilutive effect of stock options and awards	160	140	177	155
Denominator for diluted earnings per share	25,101	25,006	25,103	25,000
Net income per share, basic:	$ 1.34	$ 1.58	$ 4.25	$ 4.08
Net income per share, diluted:	$ 1.33	$ 1.57	$ 4.22	$ 4.05

Goodwill - Summary of Goodwill

Goodwill - Summary of Goodwill (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2024 USD ($)
Goodwill [Line Items]
Gross cost, beginning balance	$ 399.3
Adjustments	(3.4)
Exchange effect	(3.6)
Gross cost, ending balance	$ 392.3

Goodwill - Additional Informati

Goodwill - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2024 USD ($)
Goodwill [Line Items]
Goodwill, foreign currency translation gain (loss)	$ 3.6
Increase in fair value of net assets	(3.4)
QGP Quimica Geral [Member]
Goodwill [Line Items]
Increase in fair value of net assets	3.4
Performance Chemicals [Member]
Goodwill [Line Items]
Goodwill, foreign currency translation gain (loss)	$ 3.6

Other Intangible Assets - Summa

Other Intangible Assets - Summary of Other Intangible Assets (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Gross cost at January 1	$ 315.1
Additions	15.6
Exchange effect	1.6
Gross cost at September 30	332.3
Accumulated amortization at January 1	(257.8)
Amortization expense	(9.6)	$ (8)
Exchange effect	(1.3)
Accumulated amortization at September 30	(268.7)
Net book amount at September30	$ 63.6		$ 57.3

Other Intangible Assets - Addit

Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Jun. 30, 2024	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Amortization expense		$ 9.6	$ 8
Finite-Lived Intangible Assets, Purchase Accounting Adjustments		15.6
Intangible asset capitalized		15.6
Software Development [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Purchase Accounting Adjustments		12.1
Intangible asset capitalized		$ 12.1
QGP Quimica Geral [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Purchase Accounting Adjustments	$ 3.5
Intangible asset capitalized	$ 3.5
Finite-Lived Intangible Asset, Useful Life	7 years			10 years

Pension and Post-Employment B_3

Pension and Post-Employment Benefits - Plan Net Pension Credit (Detail) - GERMANY - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Defined Benefit Plan Disclosure [Line Items]
Service credit/(cost)	$ 7.6	$ (0.9)	$ 5.9	$ (2.7)
Interest cost on projected benefit obligation	(4.8)	(5.1)	(14.1)	(15)
Expected return on plan assets	6.5	6.5	19.3	19
Amortization of prior service cost	(0.1)	(0.2)	(0.4)	(0.4)
Amortization of actuarial net gains	0.1	0.6	0.2	1.6
Net periodic benefit	$ 9.3	$ 0.9	$ 10.9	$ 2.5

Pension and Post-Employment B_4

Pension and Post-Employment Benefits - Additional Information (Detail) - USD ($) $ in Millions	Sep. 09, 2024	Sep. 30, 2024	Dec. 31, 2023
Pension Deed [Member]
Defined Benefit Plan Disclosure [Line Items]
Repayment of historical cost	$ 8.4
Europe [Member]
Defined Benefit Plan Disclosure [Line Items]
Post-employment obligations European businesses		$ 4.2	$ 4.2

Income Taxes - Roll-forward of

Income Taxes - Roll-forward of Unrecognized Tax Benefits and Associated Accrued Interest and Penalties (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Income Tax Contingency [Line Items]
Opening balance at January 1	$ 14.8
Increase for tax positions of prior periods	0.8
Decrease for settlement of tax positions	(4.6)
Closing balance at September 30	11
Current	0	$ (1.2)
Non-current	11	$ 13.6
Interest and Penalties [Member]
Income Tax Contingency [Line Items]
Opening balance at January 1	4.3
Increase for tax positions of prior periods	0.8
Decrease for settlement of tax positions	(1.3)
Closing balance at September 30	3.8
Current	0
Non-current	3.8
Unrecognized Tax Benefits [Member]
Income Tax Contingency [Line Items]
Opening balance at January 1	10.5
Increase for tax positions of prior periods	0
Decrease for settlement of tax positions	(3.3)
Closing balance at September 30	7.2
Current	0
Non-current	$ 7.2

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Dec. 31, 2023
Income Tax Contingency [Line Items]
Unrecognized tax benefits would impact effective tax rate if recognized		$ 11
Unrecognized tax benefit		11	$ 14.8
Increase to income tax expense		0.8
Italian Tax Authorities [Member]
Income Tax Contingency [Line Items]
Unrecognized tax benefit		3.4
United Kingdom [Member] | Foreign [Member] | Profit Diversion Compliance Facility [Member]
Income Tax Contingency [Line Items]
Income tax examination penalties and interest expenses		1.2
United States [Member]
Income Tax Contingency [Line Items]
Unrecognized tax benefit		$ 11
Non-US [Member]
Income Tax Contingency [Line Items]
Open tax year		2011 2012 2013 2014
Non-US [Member] | Historical Impairment Of Subsidiaries [Member]
Income Tax Contingency [Line Items]
Decrease in uncertain tax positions	$ 11

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Detail) - USD ($) $ in Millions		9 Months Ended
	May 20, 2024	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Debt Instrument [Line Items]
Deferred finance costs, net		$ 1.2		$ 1.2
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Due date of revolving credit	May 31, 2028	May 30, 2027
Line of credit facility, maximum borrowing capacity		$ 250
Line Of Credit Facility Cumulative Drawn Down		0		$ 0
Repayment on credit facility		0	$ 0
Revolving Credit Facility [Member] | Accordion Feature [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 125

Plant Closure Provisions - Move

Plant Closure Provisions - Movements in Plant Closure and Restructuring Provisions (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Restructuring and Related Activities [Abstract]
Beginning Balance	$ 61.6
Charge for the period	2.6
Utilized in the period	(2.6)
Exchange effect	1.7
Ending Balance	63.3
Due within one year	(4.6)	$ (4.6)
Due after one year	$ 58.7	$ 57

Plant Closure Provisions - Addi

Plant Closure Provisions - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Remediation [Member]
Restructuring Cost and Reserve [Line Items]
Accretion expense recognized	$ 2.6	$ 2.7

Fair Value Measurements - Carry

Fair Value Measurements - Carrying Amount and Fair Values of the Company's Assets and Liabilities Measured on a Recurring Basis (Detail) - Recurring [Member] - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Carrying Amount [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Foreign Currency Forward Exchange Contracts [Member]
Derivatives (Level 1 measurement):
Derivatives asset	$ 0.3	$ 0
Derivatives (Level 1 measurement):
Foreign currency forward exchange contracts	0	1
Carrying Amount [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Emission Trading Scheme Credits [Member]
Derivatives (Level 1 measurement):
Derivatives asset	4.2	4.8
Carrying Amount [Member] | Significant Unobservable Inputs (Level 3) [Member]
Non-financial liabilities (Level 3 measurement):
Acquisition-related contingent consideration	21.5	23.4
Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Foreign Currency Forward Exchange Contracts [Member]
Derivatives (Level 1 measurement):
Derivatives asset	0.3	0
Derivatives (Level 1 measurement):
Foreign currency forward exchange contracts	0	1
Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Emission Trading Scheme Credits [Member]
Derivatives (Level 1 measurement):
Derivatives asset	4.2	4.8
Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member]
Non-financial liabilities (Level 3 measurement):
Acquisition-related contingent consideration	$ 21.5	$ 23.4

Derivative Instruments and Ri_2

Derivative Instruments and Risk Management - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Not Designated as Hedging Instrument [Member] | Foreign Currency Forward Exchange Contracts [Member] | Other net income/(expense) [Member]
Derivative [Line Items]
Amount of loss recognized in income	$ (1.1)	$ (1.2)

Contingencies - Additional Info

Contingencies - Additional Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Other Commitments [Line Items]
Guarantees	$ 7.1	$ 6.2
Maximum [Member]
Other Commitments [Line Items]
Fixed maturity guarantee remaining term	8 years

Stock-Based Compensation Plan_2

Stock-Based Compensation Plans - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Mar. 31, 2024
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option compensation			$ 6.4	$ 5.9
Maximum percentage of stock options granted					130%
Total compensation cost related to non-vested stock options not yet recognized	$ 23.5		$ 23.5
Expected compensation cost recognized over the weighted-average period			1 year 10 months 24 days
Stock Options Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option compensation	2.2	$ 2	$ 6.4	0.9
Stock Equivalent Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	$ 0.7	$ 2	$ 4.8	$ 7.1

Stock-Based Compensation Plan_3

Stock-Based Compensation Plans - Summary of Transactions of the Share Based Compensation Plans (Detail)	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Share-Based Payment Arrangement, Disclosure [Abstract]
Number of shares, Begining balance | shares	652,891
Number of shares, Granted | shares	139,867
Number of shares, Vested | shares	(184,170)
Number of shares, Forfeited | shares	(15,539)
Number of shares , Ending balance | shares	593,049
Weighted Average Grant-Date Fair Value , Begining balance | $ / shares	$ 75.2
Weighted Average Grant-Date Fair Value, Granted | $ / shares	130.3
Weighted Average Grant-Date Fair Value, Vested | $ / shares	86.7
Weighted Average Grant-Date Fair Value, Forfeited | $ / shares	82.2
Weighted Average Grant-Date Fair Value, Ending balance | $ / shares	$ 84.4

Reclassifications out of Accu_3

Reclassifications out of Accumulated Other Comprehensive Loss - Summary of Reclassifications out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service cost	$ 0.1	$ 0.2	$ 0.4	$ 0.4
Amortization of actuarial net gains	$ 0.1	$ 0.6	0.2	1.6
Total reclassifications			(0.1)	0.9
Defined Benefit Pension Plan Items [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications			(0.1)	0.9
Reclassification Out of Accumulated Other Comprehensive Income/(Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax			0.2	(1.2)
Income tax expense			(0.1)	0.3
Total reclassifications			0.1	(0.9)
Reclassification Out of Accumulated Other Comprehensive Income/(Loss) [Member] | Defined Benefit Pension Plan Items [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of prior service cost			0.4	0.4
Amortization of actuarial net gains			$ (0.2)	$ (1.6)

Reclassifications out of Accu_4

Reclassifications out of Accumulated Other Comprehensive Loss - Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 1,147.1
Other comprehensive income before reclassifications	2.7	$ (1.8)
Amounts reclassified from AOCL	0.1	(0.9)
Total other comprehensive income/(loss)	2.8	(2.7)
Ending Balance	1,243.4
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(148.1)	(145.2)
Ending Balance	(145.3)	(147.9)
Defined Benefit Pension Plan Items [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(77.2)	(58.4)
Other comprehensive income before reclassifications	0	0
Amounts reclassified from AOCL	0.1	(0.9)
Total other comprehensive income/(loss)	0.1	(0.9)
Ending Balance	(77.1)	(59.3)
Foreign Currency Translation Items [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(70.9)	(86.8)
Other comprehensive income before reclassifications	2.7	(1.8)
Amounts reclassified from AOCL	0	0
Total other comprehensive income/(loss)	2.7	(1.8)
Ending Balance	$ (68.2)	$ (88.6)

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Smith, Gambrell & Russell, LLP [Member]
Related Party Transaction [Line Items]
Fees incured from Smith, Gambrell & Russell	$ 200,000	$ 200,000
Other Liabilities	0		$ 0
European Metal Recycling Limited [Member]
Related Party Transaction [Line Items]
Other Liabilities	0		0
Tendering process to select best buyer of scrap metal		100,000
European Metal Recycling Limited [Member] | Maximum [Member]
Related Party Transaction [Line Items]
Tendering process to select best buyer of scrap metal	100,000
Advan Six [Member]
Related Party Transaction [Line Items]
Other Liabilities	0		$ 0
Tendering process to select best buyer of scrap metal	$ 0	$ 300,000