Entity tax identification number Entity Tax Identification Number Rollovers EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Rollover Maximum Maximum [Member] Adjustment for deemed distributed loans EBP, Reconciliation to Form 5500, Change in Net Asset Available for Benefit, Increase (Decrease) from Deemed Distribution Legal Entity [Axis] Legal Entity [Axis] Minimum annual compensation to total compensation percentage EBP, Participant Contribution, Pretax, Minimum Annual Compensation to Total Compensation, Percentage EBP, Participant Contribution, Pretax, Minimum Annual Compensation to Total Compensation, Percentage Statistical Measurement [Domain] Statistical Measurement [Domain] EBP, Description of Plan [Table] EBP, Description of Plan [Table] Mutual funds Mutual Fund [Member] EBP, Schedule Of Plan Spin Off [Line Items] EBP, Schedule Of Plan Spin Off [Line Items] EBP, Schedule Of Plan Spin Off [Line Items] Distributions and sales EBP, Investment Sold, Excluding Plan Interest in Master Trust, Selling Price EBP, Related Party and Party-in-Interest Transactions [Table] EBP, Related Party and Party-in-Interest Transactions [Table] Maximum annual compensation to total compensation percentage EBP, Participant Contribution, Pretax, Maximum Annual Compensation to Total Compensation, Percentage Total deductions EBP, Change in Net Asset Available for Benefit, Decrease Self-directed brokerage account EBP, Self-Directed Brokerage Account [Member] FAIR VALUE MEASUREMENTS EBP, Investment, Fair Value and NAV [Text Block] Number of participant loans EBP, Asset Held for Investment, Participant Loan, Number of Loans EBP, Asset Held for Investment, Participant Loan, Number of Loans Total investments Balance, January 1 Balance, December 31 EBP, Investment, Excluding Plan Interest in Master Trust, Fair Value Participant contribution match per dollar EBP, Employer Contribution, Matching, Amount Per Dollar EBP, Employer Contribution, Matching, Amount Per Dollar Money market fund Money Market Funds [Member] Level 1 Fair Value, Inputs, Level 1 [Member] EBP, Reconciliation of Financial Statement to Form 5500 EBP, Reconciliation of Financial Statement to Form 5500 [Table Text Block] Percentage of contributions allocated to applicable target date fund if no selection is made EBP, Matching Contributions Allocated To Default Fund With No Selection, Percentage EBP, Matching Contributions Allocated To Default Fund With No Selection, Percentage EBP, Investment, Fair Value and NAV [Abstract] EBP, Related Party and Party-in-Interest Transactions EBP, Related Party and Party-in-Interest Transactions [Table Text Block] Assets EBP, Asset [Abstract] Statistical Measurement [Axis] Statistical Measurement [Axis] Additions to net assets attributed to: EBP, Change in Net Asset Available for Benefit, Increase [Abstract] EBP, Statement of Change in Net Asset Available for Benefit [Table] EBP, Statement of Change in Net Asset Available for Benefit [Table] Payment of Benefits EBP, Payment to Participant [Policy Text Block] Transfer out to another plan (see Note 11) Transfer out to another plan (see Note 11) EBP, Change in Net Asset Available for Benefit, Transfer to (from) Plan Amendment Flag Amendment Flag Adjustment for deemed distributed loans EBP, Reconciliation to Form 5500, Net Asset Available for Benefit, Deemed Distribution Basis of Accounting EBP, Basis of Accounting [Policy Text Block] EBP, Schedule of Asset Held for Investment [Table] EBP, Schedule of Asset Held for Investment [Table] EBP, Description of Plan and Accounting Change [Abstract] Receivables: EBP, Receivable [Abstract] Summary of Financial Assets Measured at Fair Value EBP, Investment, Fair Value and NAV [Table Text Block] Investments [Domain] Investments [Domain] Use of Estimates EBP, Use of Estimate [Policy Text Block] Schedule H, Line 4i – Schedule of Assets (Held At End of Year) EBP, Schedule of Asset Held for Investment [Text Block] Cover [Abstract] Estimated retirement age EBP, Estimated Retirement Age EBP, Estimated Retirement Age RISKS AND UNCERTAINTIES EBP, Risk and Uncertainty [Text Block] Employer EBP, Change in Net Asset Available for Benefit, Increase from Employer Contribution, Cash Minimum Minimum [Member] Percentage of annual plan-related expenses charged per-participant EBP, Percent Of Annual Plan-Related Expenses Charged Per-Participant EBP, Percent Of Annual Plan-Related Expenses Charged Per-Participant Interest income on notes receivable from participants EBP, Change in Net Asset Available for Benefit, Increase from Interest Income on Note Receivable from Participant Investment Type [Axis] Investment Type [Axis] Total contributions EBP, Change in Net Asset Available for Benefit, Increase from Contribution Participants EBP, Change in Net Asset Available for Benefit, Increase from Participant Contribution, Excluding Rollover Net appreciation in fair value of investments Net appreciation (depreciation) in fair value EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Gain (Loss) on Investment Interest and dividends EBP, Change in Net Asset Available for Benefit, Increase from Interest and Dividend Income on Investment EBP, Description of Plan [Line Items] EBP, Description of Plan [Line Items] Plan number EBP, Plan Number EBP, Investment, Fair Value and NAV [Line Items] EBP, Investment, Fair Value and NAV [Line Items] DESCRIPTION OF PLAN EBP, Description of Plan [Text Block] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Change in Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Statement of Net Asset Available for Benefit [Table] EBP, Schedule of Asset Held for Investment [Line Items] EBP, Schedule of Asset Held for Investment [Line Items] Contributions EBP, Contribution [Policy Text Block] Pro-rated per-participant fee EBP, Pro-Rated Per-Participant Fee EBP, Pro-Rated Per-Participant Fee Tredegar Corporation common stock EBP, Employer, Common Stock [Member] EBP, Schedule of Asset Held for Investment [Abstract] Net increase after transfer out EBP, Change in Net Asset Available for Benefit, Increase (Decrease), After Transfer To (From) Plan EBP, Change in Net Asset Available for Benefit, Increase (Decrease), After Transfer To (From) Plan EBP, Accounting Policy [Table] EBP, Accounting Policy [Table] Total additions EBP, Change in Net Asset Available for Benefit, Increase EBP 002 EBP 002 [Member] EBP 002 Investment income: EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment [Abstract] Investment, Identifier [Axis] Investment, Identifier [Axis] Administrative expenses EBP, Change in Net Asset Available for Benefit, Decrease from Administrative Expense Total EBP, Asset Held for Investment CONTRIBUTIONS AND INVESTMENT OPTIONS EBP, Contributions And Investment Options [Text Block] EBP, Contributions And Investment Options Document Information [Line Items] Document Information [Line Items] EBP, Risk and Uncertainty [Line Items] EBP, Risk and Uncertainty [Line Items] EBP, Risk and Uncertainty [Table] EBP, Risk and Uncertainty [Table] Number of investment options EBP, Investment, Offered, Number Of Investments EBP, Investment, Offered, Number Of Investments Participant compensation matched EBP, Employer Contribution, Participant Compensation Matched, Percentage EBP, Statement of Change in Net Asset Available for Benefit [Abstract] PLAN SPIN OFF Plan Spin Off [Text Block] Plan Spin Off Net income per Form 5500 EBP, Form 5500 Caption, Net Income (Loss) EBP, Forfeitures [Abstract] EBP, Forfeitures [Abstract] EBP, Tax Status [Table] EBP, Tax Status [Table] Net increase before transfers Net increase per Statements of Changes in Net Assets Available for Benefits EBP, Change in Net Asset Available for Benefit, Increase (Decrease) RELATED PARTY AND PARTY IN INTEREST TRANSACTIONS EBP, Related Party and Party-in-Interest Transactions [Text Block] EBP, Related Party and Party-in-Interest Transactions [Abstract] EBP, Accounting Policy, Accounting Standard Update, and Change in Accounting Principle [Abstract] Total receivables EBP, Receivable Deferral rate EBP, Participant Contribution, Automatic, Deferral Rate Investments, at fair value: EBP, Investment, Fair Value [Abstract] Benefits paid to participating employees EBP, Change in Net Asset Available for Benefit, Decrease from Payment to Participant Current Value EBP, Asset Held for Investment, Investment, Excluding Plan Interest in Master Trust, Current Value Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] EBP, Statement of Net Asset Available for Benefit [Abstract] EBP, Schedule Of Plan Spin Off [Table] EBP, Schedule Of Plan Spin Off [Table] EBP, Schedule Of Plan Spin Off [Table] EBP, Accounting Policy [Line Items] EBP, Accounting Policy [Line Items] EBP, Tax Status [Abstract] EBP, Reconciliation of Financial Statement to Form 5500 [Table] EBP, Reconciliation of Financial Statement to Form 5500 [Table] EBP, Reconciliation of Financial Statement to Form 5500 [Line Items] EBP, Reconciliation of Financial Statement to Form 5500 [Line Items] Administrative Expenses EBP, Expense [Policy Text Block] RECONCILIATION OF FINANCIAL STATEMENTS TO FORM 5500 EBP, Reconciliation of Financial Statement to Form 5500 [Text Block] Participant loans EBP, Asset Held for Investment, Participant Loan, after Deemed Distribution Investment Valuation and Income Recognition EBP, Investment [Policy Text Block] Fair Value, Inputs, Level 1, Level 2, and Level 3 Fair Value, Inputs, Level 1, Level 2, and Level 3 [Member] Document Type Document Type PLAN TERMINATION EBP, Plan Termination [Text Block] Entity Central Index Key Entity Central Index Key Participant loan, interest rate EBP, Asset Held for Investment, Participant Loan, Interest Rate EBP, Reconciliation of Financial Statement to Form 5500 [Abstract] Common collective trust Common Collective Trust [Member] EBP, Risk and Uncertainty [Abstract] EBP, Tax Status [Line Items] EBP, Tax Status [Line Items] Annual limit of other administrative expenses EBP, Administrative Expense, Employer Paid, Maximum Annual Limit EBP, Administrative Expense, Employer Paid, Maximum Annual Limit Deductions from net assets attributed to: EBP, Change in Net Asset Available for Benefit, Decrease [Abstract] Notes receivable from participants EBP, Note Receivable from Participant Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES EBP, Summary of Accounting Policy [Text Block] Entity Registrant Name Entity Registrant Name Participant loan, cost EBP, Asset Held for Investment, Participant Loan, Cost EBP, Asset Held for Investment, Participant Loan, Cost Plan Spin Off [Abstract] Plan Spin Off [Abstract] Subsequent Events EBP, Subsequent Event [Policy Text Block] INCOME TAX STATUS EBP, Tax Status [Text Block] Document Information [Table] Document Information [Table] Total administrative expenses EBP, Administrative Expense, Decrease EBP, Administrative Expense, Decrease Notes Receivable from Participants EBP, Note Receivable from Participant [Policy Text Block] EBP, Related Party And Party-in-Interest Transactions [Roll Forward] EBP, Related Party And Party-in-Interest Transactions [Roll Forward] EBP, Related Party And Party-in-Interest Transactions Total investment gain EBP, Change in Net Asset Available for Benefit, Increase (Decrease) from Income (Loss) on Investment Redemption, notice period EBP, Fair Value, Investment, NAV, Redemption, Notice Period EBP, Related Party and Party-in-Interest Transactions [Line Items] EBP, Related Party and Party-in-Interest Transactions [Line Items] Net increase after transfer out Beginning of year End of year Net assets available for benefits per Statements of Net Assets Available for Benefits EBP, Net Asset Available for Benefit Entity [Domain] Entity [Domain] Contributions: EBP, Change in Net Asset Available for Benefit, Increase from Contribution [Abstract] Forfeited accounts available EBP, Forfeited Nonvested Account Net assets available for benefits per the Form 5500 EBP, Form 5500 Caption, Net Assets Investments measured at NAV Fair Value Measured at Net Asset Value Per Share [Member] EBP, Investment, Fair Value and NAV [Table] EBP, Investment, Fair Value and NAV [Table] EBP, Statement of Net Asset Available for Benefit [Line Items] EBP, Statement of Net Asset Available for Benefit [Line Items] FORFEITURES EBP, Forfeitures [Text Block] EBP, Forfeitures