BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2026
Basis Of Presentation [Abstract]
BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	1. BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Tredegar Corporation is engaged, through its subsidiaries, in the manufacture of aluminum extrusions and polyethylene and polypropylene plastic films. Unless the context requires otherwise, all references herein to “Tredegar,” “the Company,” “we,” “us” or “our” are to Tredegar Corporation and its consolidated subsidiaries. In the opinion of management, the accompanying condensed consolidated financial statements of the Company contain all adjustments necessary to state fairly, in all material respects, Tredegar’s condensed consolidated financial position as of March 31, 2026, the condensed consolidated results of operations for the three months ended March 31, 2026 and 2025, the condensed consolidated cash flows for the three months ended March 31, 2026 and 2025, and the condensed consolidated changes in shareholders’ equity for the three months ended March 31, 2026 and 2025, in accordance with U.S. generally accepted accounting principles (“GAAP”). All such adjustments, unless otherwise detailed in the notes to the condensed consolidated financial statements, are deemed to be of a normal, recurring nature. The Company operates on a calendar fiscal year except for the Aluminum Extrusions segment, which operates on a 52/53-week fiscal year basis. As such, the fiscal first quarter for 2026 and 2025 for this segment references 13-week periods ended March 29, 2026 and March 30, 2025, respectively. The Company does not believe the impact of reporting the results of this segment as stated above is material to the consolidated financial results. The Company may fund or receive cash from the Aluminum Extrusions segment based on Aluminum Extrusions' cash flows from operations during the intervening period from Aluminum Extrusions' fiscal quarter end and the Company’s fiscal quarter end. As a result, the Company’s prepaid and other current assets increased by $5.7 million as of December 31, 2025 since the Company made payments to the Aluminum Extrusions segment to fund its payroll during the intervening period between December 28, 2025 and December 31, 2025. There was no intercompany funding with Aluminum Extrusions between March 29, 2026 and March 31, 2026. The condensed consolidated financial statements as of December 31, 2025 that is included herein was derived from the audited consolidated financial statements provided in the Company’s Annual Report on Form 10-K for the year ended December 31, 2025 (“2025 Form 10-K”) but does not include all disclosures required by GAAP. These financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in the 2025 Form 10-K. The results of operations for the three months ended March 31, 2026, are not necessarily indicative of the results to be expected for the full year. In the fourth quarter of 2025, the Company renamed the segment formerly known as “PE Films.” This segment is now referred to as “High Performance Films.” The product previously known as polyethylene overwrap films was renamed to advanced packaging films. There were no changes to the operations reported within the High Performance Films segment. The Company continues to have two reportable segments: Aluminum Extrusions and High Performance Films. More information on the Company’s business segments is provided in Note 9. Sale of Flexible Packaging Films On November 1, 2024, the Company completed the sale of its flexible packaging films business (also referred to as “Terphane”) headquartered in Brazil to Oben Group (“Oben”). Commencing in the fourth quarter of 2024, all historical results for Terphane have been presented as discontinued operations. For more information on this transaction, see Note 10. Accounting standards not yet adopted In October 2023, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2023-06 to amend various paragraphs in the Accounting Standards Codification ("ASC") to primarily reflect the issuance of U.S. Securities and Exchange Commission ("SEC") Staff Bulletin No. 33-10532. ASU 2023-06 will impact various disclosure areas, including the statement of cash flows, accounting changes and error corrections, earnings per share, debt, equity, derivatives, and transfers of financial assets. The amendments in this ASU 2023-06 will be effective on the date the related disclosures are removed from Regulation S-X or Regulation S-K by the SEC and will no longer be effective if the SEC has not removed the applicable disclosure requirement by June 30, 2027. Early adoption is not permitted. The Company does not expect a material impact from the adoption of this standard on our consolidated financial statements and related disclosures. In November 2024, the FASB issued ASU 2024-03 to improve the disclosures about public business entity’s expenses and address requests from investors for more detailed information about the types of expenses in commonly presented expense captions. The amendments in this ASU will require the Company to disclose specified information about certain costs and expenses in the notes to the financial statements. This ASU is effective for annual periods beginning after December 15, 2026 and interim periods beginning after December 15, 2027. Early adoption is permitted. The Company is currently evaluating the impact of this standard on our consolidated financial statements and related disclosures. In December 2025, the FASB issued ASU 2025-11 to amend the guidance in “Interim Reporting” (Topic 270). The update provides clarifications intended to improve the consistency and usability of interim disclosure requirements, including a comprehensive listing of required interim disclosures and a new disclosure principle for reporting material events occurring after the most recent annual period. The amendments do not change the underlying objectives of interim reporting but are designed to enhance clarity in application. The guidance is effective for fiscal years beginning after December 15, 2027, including interim periods within those fiscal years. The Company does not expect a material impact from the adoption of this standard on our consolidated financial statements and related disclosures.