Financial Statement Presentation	6 Months Ended
Jun. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Financial Statement Presentation	Financial Statement Presentation In the opinion of management, the accompanying consolidated financial statements of NewMarket Corporation and its subsidiaries contain all necessary adjustments for the fair presentation of, in all material respects, our consolidated financial position as of June 30, 2025 and December 31, 2024, our consolidated results of operations, comprehensive income, and changes in shareholders' equity for the second quarter and six months ended June 30, 2025 and June 30, 2024, and our cash flows for the six months ended June 30, 2025 and June 30, 2024. All adjustments are of a normal, recurring nature, unless otherwise disclosed. These financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) for interim financial information and the instructions to Rule 10-01 of Regulation S-X of the Securities and Exchange Commission (SEC), but do not include all disclosures required by GAAP for complete annual consolidated financial statements. These financial statements should be read in conjunction with the consolidated financial statements and related notes included in the NewMarket Corporation Annual Report on Form 10-K for the year ended December 31, 2024 (2024 Annual Report), as filed with the SEC. The results of operations for the six-month period ended June 30, 2025 are not necessarily indicative of the results to be expected for the full year ending December 31, 2025. Unless the context otherwise indicates, all references to “we,” “us,” “our,” the “company,” and “NewMarket” are to NewMarket Corporation and its consolidated subsidiaries. Supplier Finance Program We offer our vendors a supplier finance program, which allows our vendors to receive payment from a third-party finance provider earlier than our normal payment terms would provide. NewMarket and its subsidiaries are not a party to any arrangement between our vendors and the finance provider, and there are no assets pledged as security or other forms of guarantees provided by NewMarket to the finance provider. For those vendors who opt to participate in the program, we pay the finance provider the full amount of the invoices on the normal due date. At both June 30, 2025 and December 31, 2024, the amount of confirmed invoices under the supplier finance program was not material.
Supplier Finance Program	We offer our vendors a supplier finance program, which allows our vendors to receive payment from a third-party finance provider earlier than our normal payment terms would provide. NewMarket and its subsidiaries are not a party to any arrangement between our vendors and the finance provider, and there are no assets pledged as security or other forms of guarantees provided by NewMarket to the finance provider. For those vendors who opt to participate in the program, we pay the finance provider the full amount of the invoices on the normal due date.

Financial Statement Presentation

6 Months Ended

Jun. 30, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

In the opinion of management, the accompanying consolidated financial statements of NewMarket Corporation and its subsidiaries contain all necessary adjustments for the fair presentation of, in all material respects, our consolidated financial position as of June 30, 2025 and December 31, 2024, our consolidated results of operations, comprehensive income, and changes in shareholders' equity for the second quarter and six months ended June 30, 2025 and June 30, 2024, and our cash flows for the six months ended June 30, 2025 and June 30, 2024. All adjustments are of a normal, recurring nature, unless otherwise disclosed. These financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) for interim financial information and the instructions to Rule 10-01 of Regulation S-X of the Securities and Exchange Commission (SEC), but do not include all disclosures required by GAAP for complete annual consolidated financial statements. These financial statements should be read in conjunction with the consolidated financial statements and related notes included in the NewMarket Corporation Annual Report on Form 10-K for the year ended December 31, 2024 (2024 Annual Report), as filed with the SEC. The results of operations for the six-month period ended June 30, 2025 are not necessarily indicative of the results to be expected for the full year ending December 31, 2025.

Unless the context otherwise indicates, all references to “we,” “us,” “our,” the “company,” and “NewMarket” are to NewMarket Corporation and its consolidated subsidiaries.

Supplier Finance Program

We offer our vendors a supplier finance program, which allows our vendors to receive payment from a third-party finance provider earlier than our normal payment terms would provide. NewMarket and its subsidiaries are not a party to any arrangement between our vendors and the finance provider, and there are no assets pledged as security or other forms of guarantees provided by NewMarket to the finance provider. For those vendors who opt to participate in the program, we pay the finance provider the full amount of the invoices on the normal due date. At both June 30, 2025 and December 31, 2024, the amount of confirmed invoices under the supplier finance program was not material.

Supplier Finance Program