General (Policies)	6 Months Ended
General (Policies)	Jun. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements and the notes thereto have been prepared in accordance with the instructions on Form 10-Q and Rule 10-01 of Regulation S-X of the Securities and Exchange Commission ("SEC") and do not include all the information and disclosures required by accounting principles generally accepted in the United States of America ("GAAP"). However, such information reflects all adjustments (consisting of normal recurring adjustments) which are, in the opinion of management, necessary for a fair statement of results for the interim periods. The results of operations for the three and six months ended June 30, 2023 are not necessarily indicative of the results to be expected for the full year. The unaudited condensed consolidated financial statements and these notes thereto included herein should be read in conjunction with the audited consolidated financial statements and the related notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022, as filed with the SEC on March 1, 2023.
Reclassifications	ReclassificationsCertain prior year amounts on the unaudited Condensed Consolidated Statements of Cash Flows have been reclassified to conform to the current year presentation for comparative purposes. Prior year's classification of certain end markets in the legacy SWM Advanced Materials & Structures segment have been reclassified to conform to the current year presentation of ATM's end markets for comparative purposes.
Principles of Consolidation	Principles of Consolidation The unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned, majority-owned and controlled subsidiaries. The Company’s share of the net income of its 50%-owned joint ventures in China is included in the unaudited Condensed Consolidated Statements of Income (Loss) as Income from equity affiliates, net of income taxes. Intercompany balances and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the revenues and expenses during the reporting period. Actual results could differ significantly from these estimates. The significant estimates underlying our unaudited condensed consolidated financial statements include, but are not limited to, inventory valuation, useful lives of tangible and intangible assets, business acquisitions, equity-based compensation, derivatives, receivables valuation, pension, postretirement and other benefits, taxes and contingencies.
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards In March 2020, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2020-04, "Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting." The new standard provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform and the anticipated discontinuance of the London Interbank Offered Rate ("LIBOR") if certain criteria are met. The amendments in this ASU are effective for all entities as of March 12, 2020 through December 31, 2022. In December 2022, FASB issued ASU 2022-06, "Reference Rate Reform (Topic 848): Deferral of the Sunset Date of Topic 848", which extended the final sunset date from December 31, 2022 to December 31, 2024. The provisions of ASU 2020-04 and ASU 2022-06 were adopted effective April 1, 2022 and December 21, 2022, respectively, and did not have a material impact on the unaudited condensed consolidated financial statements.