Basis Of Presentation	9 Months Ended
Basis Of Presentation	Sep. 30, 2024
Basis Of Presentation [Abstract]
Basis Of Presentation	In the opinion of management, the accompanying condensed consolidated financial statements of Tredegar Corporation and its subsidiaries (“Tredegar,” “the Company,” “we,” “us” or “our”) contain all adjustments necessary to state fairly, in all material respects, Tredegar’s condensed consolidated financial position as of September 30, 2024, the condensed consolidated results of operations for the three and nine months ended September 30, 2024 and 2023, the condensed consolidated cash flows for the nine months ended September 30, 2024 and 2023, and the condensed consolidated changes in shareholders’ equity for the three and nine months ended September 30, 2024 and 2023, 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 third quarter for 2024 and 2023 for this segment references 13-week periods ended September 29, 2024 and September 24, 2023, 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 Extrusion’s cash flows from operations during the intervening period from Aluminum Extrusion’s fiscal quarter end and the Company’s fiscal quarter end. The condensed consolidated financial statements as of December 31, 2023 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, 2023 (“2023 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 2023 Form 10-K. The results of operations for the three and nine months ended September 30, 2024, are not necessarily indicative of the results to be expected for the full year. Sale of Flexible Packaging Films On September 1, 2023, the Company announced that it had entered into a definitive agreement to sell its Flexible Packaging Films business (also referred to as "Terphane") to Oben Group (the "Terphane Sale"). Completion of the sale is contingent upon the satisfaction of customary closing conditions, including the receipt of certain competition filing approvals by authorities in Brazil and Colombia. The Colombian authority cleared the merger review regarding the transaction in early February 2024. On October 27, 2023, the Company filed the requisite competition forms with the Administrative Council for Economic Defense (“CADE”) in Brazil. As part of the Brazilian merger review process regarding the sale of Terphane to Oben Group ("Oben"), on May 13, 2024, the General Superintendence of the Administrative Council for Economic Defense ("SG-CADE") issued a non-binding opinion ("SG Opinion") recommending the rejection of the transaction. Following this first stage of the two-stage Brazilian merger review process for complex transactions, the case was submitted to the CADE Tribunal, in accordance with the customary Brazilian merger review process. As of September 30, 2024, the Company reported results for Terphane as a continuing operation, due to the uncertainty related to the Brazilian merger review process. On October 16, 2024, CADE approved a merger control agreement allowing Tredegar to proceed with the sale of Terphane to Oben. This approval was the indication that the sale of Terphane was probable. Refer to Note 11 for additional information. Closure of PE Films Technical Center In August 2023, the Company adopted a plan to close the PE Films technical center in Richmond, VA and reduce its efforts to develop and sell films supporting the semiconductor market. Research & development activities for PE Films are now being performed at the production facility in Pottsville, PA. PE Films continues to have new business opportunities primarily relating to surface protection films that protect components of flat panel and flexible displays. All activities ceased at the PE Films technical center in Richmond, VA as of the end of the first quarter of 2024. The Company recognized expense incurred through September 30, 2024 associated with the exit activities of $0.2 million for building closure costs. In addition, the Company recognized a non-cash loss on the lease abandonment ($0.3 million). Supply Chain Financing As of September 30, 2024 and December 31, 2023, $11.8 million and $15.8 million, respectively, of the Company’s accounts payable were financed by participating suppliers through third-party financial institutions. Goodwill The Company assesses goodwill for impairment when events or circumstances indicate that the carrying value may not be recoverable, or, at a minimum, on an annual basis (December 1st of each year). As of September 30, 2024, the Company’s reporting units with goodwill were Surface Protection in PE Films ("Surface Protection") and Futura in Aluminum Extrusions (“Futura”). No events or circumstances were identified during the third quarter of 2024 that indicate that Surface Protection's fair value is more likely than not less than its carrying amount. No events or circumstances were identified during the third quarter of 2023 that indicated that Futura’s fair value was more likely than not less than its carrying amount. Uncertainty about the timing of a recovery in the consumer electronics market persists, and manufacturers in the supply chain for consumer electronics continue to experience reduced capacity utilization and inventory corrections. In light of the limited visibility on the timing of a recovery and the expected adverse future impact to the Surface Protection business, coupled with a cautious outlook on new product development opportunities, the Company performed a Step 1 goodwill impairment analysis of the Surface Protection component of PE Films, as of September 30, 2023. This analysis utilized projections that contemplate the expected market recovery and business conditions, including for its three significant customers, as these events indicated Surface Protection’s fair value is more likely than not less than its carrying amount. The Company estimated the fair value of Surface Protection at September 30, 2023 by: (i) computing an estimated enterprise value (“EV”) utilizing the discounted cash flow method (the “DCF Method”), (ii) applying adjustments for any surplus or deficient working capital, (iii) adding cash and cash equivalents, and (iv) subtracting interest-bearing debt. The DCF Method was used, incorporating Surface Protection’s latest projections which reflect updated expected market recovery levels, feasibility of launching new product applications, competitive pricing and cash flows associated with production efficiencies, as well as consideration of cost savings and inventory corrections. The analysis concluded that the fair value of Surface Protection was less than its carrying value, thus a non-cash partial goodwill impairment of $19.5 million ($15.1 million after deferred income tax benefits) was recognized during the third quarter of 2023 and $34.9 million ($27.0 million after deferred income tax benefits) during the first nine months of 2023. Accounting standards not yet adopted