Investments	12 Months Ended
Dec. 31, 2021
Equity Method Investments and Joint Ventures [Abstract]
Investments	16. INVESTMENTSIn August 2007 and December 2008, the Company made an aggregate investment of $7.5 million in kaleo, Inc. (“kaléo”), a privately held specialty pharmaceutical company dedicated to building innovative solutions for serious and life-threatening medical conditions. Tredegar historically accounted for its investment in kaléo under the fair value option. At the time of the initial investment, the Company elected the fair value option of accounting since its investment objectives were similar to those of venture capitalists, which typically do not have controlling financial interests. kaléo’s stock is not publicly traded.On December 27, 2021, the Company completed the sale of its investment interests in kaléo (Series A-3 Preferred Stock, Series B Preferred Stock and common stock) that, taken together, represented on a fully-diluted basis an approximate 18% interest in kaléo. Tredegar received closing cash proceeds of $47.1 million. A pre-tax gain of $12.8 million on the Company’s investment in kaléo was recognized in the full year ended December 31, 2021 compared to a pre-tax loss of $60.9 million and pre-tax gain of $28.5 million in the full years ended December 31, 2020 and 2019, respectively, which are reported in “Other income (expense), net” in the consolidated statements of income.

Investments

12 Months Ended

Dec. 31, 2021

Equity Method Investments and Joint Ventures [Abstract]

16. INVESTMENTSIn August 2007 and December 2008, the Company made an aggregate investment of $7.5 million in kaleo, Inc. (“kaléo”), a privately held specialty pharmaceutical company dedicated to building innovative solutions for serious and life-threatening medical conditions. Tredegar historically accounted for its investment in kaléo under the fair value option. At the time of the initial investment, the Company elected the fair value option of accounting since its investment objectives were similar to those of venture capitalists, which typically do not have controlling financial interests. kaléo’s stock is not publicly traded.On December 27, 2021, the Company completed the sale of its investment interests in kaléo (Series A-3 Preferred Stock, Series B Preferred Stock and common stock) that, taken together, represented on a fully-diluted basis an approximate 18% interest in kaléo. Tredegar received closing cash proceeds of $47.1 million. A pre-tax gain of $12.8 million on the Company’s investment in kaléo was recognized in the full year ended December 31, 2021 compared to a pre-tax loss of $60.9 million and pre-tax gain of $28.5 million in the full years ended December 31, 2020 and 2019, respectively, which are reported in “Other income (expense), net” in the consolidated statements of income.