Investments	12 Months Ended
Dec. 31, 2017
Equity Method Investments and Joint Ventures [Abstract]
Investments	INVESTMENTS In August 2007 and December 2008, Tredegar 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. The mission of kaléo is to provide products that empower patients to confidently take control of their medical conditions. Tredegar owns Series A-3 Preferred Stock and Series B Preferred Stock in kaléo that, taken together, represents on a fully-diluted basis an approximate 20% interest in kaléo. Tredegar accounts for its investment in kaléo under the fair value method. 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. At December 31, 2017 and 2016, the estimated fair value of the Company’s investment (also the carrying value, which is separately stated in the consolidated balance sheets) was $54.0 million and $20.2 million, respectively. The Company recognized an unrealized gain on its investment in kaléo of $33.8 million ($24.0 million after taxes) and $1.6 million ($1.2 million after taxes) in 2017 and 2016, respectively. The change in the estimated fair value of the Company’s holding in kaléo in 2017 primarily related to recent favorable operating results and projections. Kaléo’s stock is not publicly traded. In addition, kaléo had not completed a full year of operations since the re-launch of its Auvi-Q® product which occurred during the first quarter of 2017. The valuation estimate in this situation is based on projection assumptions or Level 3 inputs that have a wide range of possible outcomes. Consequently, the present value of kaléo’s projected future cash flows is determined at a discount rate of 45% for their high degree of risk. Ultimately, the true value of the Company’s ownership interest in kaléo will be determined if and when a liquidity event occurs, and the ultimate value could be materially different from the $54.0 million estimated fair value reflected in the Company’s financial statements at December 31, 2017. The Company recognized an unrealized loss of $20.5 million ($15.7 million after taxes) in 2015 that primarily related to a voluntary recall of the epinephrine auto-injectors that were on the market which was announced on October 28, 2015 by sanofi-aventis U.S. LLC to whom kaléo had licensed exclusive rights to commercialize the epinephrine auto-injectors at that time. Kaléo relaunched the epinephrine auto-injector in the U.S. in the first quarter of 2017. Unrealized gains (losses) associated with this investment are included in “Other income (expense), net” in the consolidated statements of income and separately stated in the segment operating profit table in Note 5. Subsequent to its most recent investment (December 15, 2008), and until the next round of financing, the Company believes fair value estimates are based upon Level 3 inputs since there is no secondary market for its ownership interest. Accordingly, until the next round of financing or any other significant financial transaction, value estimates will primarily be based on assumptions related to meeting cash flow projections and discounting of these factors for their high degree of risk. If kaléo does not meet its projected cash flows or related risks are unfavorable versus the most recent valuation, or a new round of financing or other significant financial transaction indicates a lower enterprise value, then the Company’s estimate of the fair value of its ownership interest in kaléo is likely to decline. Adjustments to the estimated fair value of this investment will be made in the period upon which such changes can be quantified. In addition to the impact on valuation of the possible changes in assumptions, Level 3 inputs and projections from changes in business conditions, the fair market valuation of Tredegar’s interest in kaléo is sensitive to changes in the weighted average cost of capital used to discount cash flow projections for the high degree of risk associated with a wide range of possible outcomes. The weighted average cost of capital used in the fair market valuation of the Company’s interest in kaléo was 45% at both December 31, 2017 and 2016. At December 31, 2017, the effect of a 500 basis point decrease in the weighted average cost of capital assumption would have further increased the fair value of Tredegar’s interest in kaléo by approximately $11 million, and a 500 basis point increase in the weighted average cost of capital assumption would have decreased the fair value of the Company’s interest by approximately $10 million. On April 2, 2007, Tredegar invested $10.0 million in Harbinger Capital Partners Special Situations Fund, L.P. (the “Harbinger Fund”), a private investment fund that is subject to limitations on withdrawal. There is no secondary market for interests in the fund. The Company’s investment in the Harbinger Fund, which represents less than 1% of its total partnership capital, is accounted for under the cost method. There were no unrealized gains or losses on the Company’s investment in the Harbinger Fund in 2017, 2016 and 2015. The December 31, 2017 and 2016 carrying values in the consolidated balance sheets (included in “Other assets and deferred charges”) were $1.7 million and $1.7 million, respectively. The carrying value at December 31, 2017 reflected Tredegar’s cost basis in its investment in Harbinger, net of total withdrawal proceeds received and unrealized losses. Withdrawal proceeds were $0.1 million in 2015 (none in 2017 and 2016). The timing and amount of future installments of withdrawal proceeds was not known as of December 31, 2017. There were no realized gains or losses associated with the investment in the Harbinger Fund in 2017, 2016 and 2015. Gains on the Company’s investment in the Harbinger Fund, if any, will be recognized when the amounts expected to be collected from withdrawal from the investment are known, which will likely be when cash in excess of the remaining carrying value is received. Losses will be recognized if management believes it is probable that future withdrawal proceeds will not exceed the remaining carrying value. Tredegar has investment property in Alleghany and Bath counties, Virginia. In 2016, the Company recorded an unrealized loss on this investment property of $1.0 million ($0.7 million after taxes) as a reduction in the estimated fair value of the investment that is not expected to be temporary. The Company’s carrying value in this investment property (included in “Other assets and deferred charges” on the consolidated balance sheets) was $1.6 million at December 31, 2017 and $1.6 million at December 31, 2016.

INVESTMENTS

In August 2007 and December 2008, Tredegar 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. The mission of kaléo is to provide products that empower patients to confidently take control of their medical conditions. Tredegar owns Series A-3 Preferred Stock and Series B Preferred Stock in kaléo that, taken together, represents on a fully-diluted basis an approximate 20% interest in kaléo. Tredegar accounts for its investment in kaléo under the fair value method. 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.

At December 31, 2017 and 2016, the estimated fair value of the Company’s investment (also the carrying value, which is separately stated in the consolidated balance sheets) was $54.0 million and $20.2 million, respectively. The Company recognized an unrealized gain on its investment in kaléo of $33.8 million ($24.0 million after taxes) and $1.6 million ($1.2 million after taxes) in 2017 and 2016, respectively.

The change in the estimated fair value of the Company’s holding in kaléo in 2017 primarily related to recent favorable operating results and projections. Kaléo’s stock is not publicly traded. In addition, kaléo had not completed a full year of operations since the re-launch of its Auvi-Q® product which occurred during the first quarter of 2017. The valuation estimate in this situation is based on projection assumptions or Level 3 inputs that have a wide range of possible outcomes. Consequently, the present value of kaléo’s projected future cash flows is determined at a discount rate of 45% for their high degree of risk. Ultimately, the true value of the Company’s ownership interest in kaléo will be determined if and when a liquidity event occurs, and the ultimate value could be materially different from the $54.0 million estimated fair value reflected in the Company’s financial statements at December 31, 2017.

The Company recognized an unrealized loss of $20.5 million ($15.7 million after taxes) in 2015 that primarily related to a voluntary recall of the epinephrine auto-injectors that were on the market which was announced on October 28, 2015 by sanofi-aventis U.S. LLC to whom kaléo had licensed exclusive rights to commercialize the epinephrine auto-injectors at that time. Kaléo relaunched the epinephrine auto-injector in the U.S. in the first quarter of 2017.

Unrealized gains (losses) associated with this investment are included in “Other income (expense), net” in the consolidated statements of income and separately stated in the segment operating profit table in Note 5. Subsequent to its most recent investment (December 15, 2008), and until the next round of financing, the Company believes fair value estimates are based upon Level 3 inputs since there is no secondary market for its ownership interest. Accordingly, until the next round of financing or any other significant financial transaction, value estimates will primarily be based on assumptions related to meeting cash flow projections and discounting of these factors for their high degree of risk. If kaléo does not meet its projected cash flows or related risks are unfavorable versus the most recent valuation, or a new round of financing or other significant financial transaction indicates a lower enterprise value, then the Company’s estimate of the fair value of its ownership interest in kaléo is likely to decline. Adjustments to the estimated fair value of this investment will be made in the period upon which such changes can be quantified.

In addition to the impact on valuation of the possible changes in assumptions, Level 3 inputs and projections from changes in business conditions, the fair market valuation of Tredegar’s interest in kaléo is sensitive to changes in the weighted average cost of capital used to discount cash flow projections for the high degree of risk associated with a wide range of possible outcomes. The weighted average cost of capital used in the fair market valuation of the Company’s interest in kaléo was 45% at both December 31, 2017 and 2016. At December 31, 2017, the effect of a 500 basis point decrease in the weighted average cost of capital assumption would have further increased the fair value of Tredegar’s interest in kaléo by approximately $11 million, and a 500 basis point increase in the weighted average cost of capital assumption would have decreased the fair value of the Company’s interest by approximately $10 million.

On April 2, 2007, Tredegar invested $10.0 million in Harbinger Capital Partners Special Situations Fund, L.P. (the “Harbinger Fund”), a private investment fund that is subject to limitations on withdrawal. There is no secondary market for interests in the fund. The Company’s investment in the Harbinger Fund, which represents less than 1% of its total partnership capital, is accounted for under the cost method. There were no unrealized gains or losses on the Company’s investment in the Harbinger Fund in 2017, 2016 and 2015. The December 31, 2017 and 2016 carrying values in the consolidated balance sheets (included in “Other assets and deferred charges”) were $1.7 million and $1.7 million, respectively. The carrying value at December 31, 2017 reflected Tredegar’s cost basis in its investment in Harbinger, net of total withdrawal proceeds received and unrealized losses. Withdrawal proceeds were $0.1 million in 2015 (none in 2017 and 2016). The timing and amount of future installments of withdrawal proceeds was not known as of December 31, 2017. There were no realized gains or losses associated with the investment in the Harbinger Fund in 2017, 2016 and 2015. Gains on the Company’s investment in the Harbinger Fund, if any, will be recognized when the amounts expected to be collected from withdrawal from the investment are known, which will likely be when cash in excess of the remaining carrying value is received. Losses will be recognized if management believes it is probable that future withdrawal proceeds will not exceed the remaining carrying value.

Tredegar has investment property in Alleghany and Bath counties, Virginia. In 2016, the Company recorded an unrealized loss on this investment property of $1.0 million ($0.7 million after taxes) as a reduction in the estimated fair value of the investment that is not expected to be temporary. The Company’s carrying value in this investment property (included in “Other assets and deferred charges” on the consolidated balance sheets) was $1.6 million at December 31, 2017 and $1.6 million at December 31, 2016.