Debt Instrument, Basis Spread On Variable Rate, Floor

No definition available.

Name:	tg_DebtInstrumentBasisSpreadOnVariableRateFloor
Namespace Prefix:	tg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Borrowing Base Calculation, Amount Of Eligible Cash, Cap, Percentage Of Borrowing Base

+ References

No definition available.

+ Details

Name:	tg_DebtInstrumentBorrowingBaseCalculationAmountOfEligibleCashCapPercentageOfBorrowingBase
Namespace Prefix:	tg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Borrowing Base Calculation, Property Plant And Equipment Component Threshold, Percentage Of Borrowing Base

+ References

No definition available.

+ Details

Name:	tg_DebtInstrumentBorrowingBaseCalculationPropertyPlantAndEquipmentComponentThresholdPercentageOfBorrowingBase
Namespace Prefix:	tg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Borrowing Base Calculation, Property Plant And Equipment Component Threshold, Percentage Of Net Orderly Liquidation Value

+ References

No definition available.

+ Details

Name:	tg_DebtInstrumentBorrowingBaseCalculationPropertyPlantAndEquipmentComponentThresholdPercentageOfNetOrderlyLiquidationValue
Namespace Prefix:	tg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line Of Credit, Cash Dominion Period, Monetary Availability Threshold

+ References

No definition available.

+ Details

Name:	tg_LineOfCreditCashDominionPeriodMonetaryAvailabilityThreshold
Namespace Prefix:	tg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line Of Credit, Cash Dominion Period, Percentage Threshold

+ References

No definition available.

+ Details

Name:	tg_LineOfCreditCashDominionPeriodPercentageThreshold
Namespace Prefix:	tg_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of Credit Facility, percent borrowing capacity

+ References

No definition available.

+ Details

Name:	tg_LineOfCreditFacilityPercentBorrowingCapacity
Namespace Prefix:	tg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of Credit Facility, Unused Capacity, Commitment Fee Percentage, Threshold

+ References

No definition available.

+ Details

Name:	tg_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentageThreshold
Namespace Prefix:	tg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line Of Credit, Fixed Charge Coverage Ratio, Monetary Availability Threshold

+ References

No definition available.

+ Details

Name:	tg_LineOfCreditFixedChargeCoverageRatioMonetaryAvailabilityThreshold
Namespace Prefix:	tg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line Of Credit, Fixed Charge Coverage Ratio, Percentage Threshold

+ References

No definition available.

+ Details

Name:	tg_LineOfCreditFixedChargeCoverageRatioPercentageThreshold
Namespace Prefix:	tg_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of Credit, Maximum Borrowing Capacity after ABL Adjustment Date

+ References

No definition available.

+ Details

Name:	tg_LineOfCreditMaximumBorrowingCapacityAfterABLAdjustmentDate
Namespace Prefix:	tg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Minimum Availability after ABL Adjustment Date

+ References

No definition available.

+ Details

Name:	tg_MinimumAvailabilityAfterABLAdjustmentDate
Namespace Prefix:	tg_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Minimum Availability, Dollar Threshold

+ References

No definition available.

+ Details

Name:	tg_MinimumAvailabilityDollarThreshold
Namespace Prefix:	tg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of assets pledged to secure a debt instrument.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477734/942-470-50-3

+ Details

Name:	us-gaap_DebtInstrumentCollateralAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 605
-Name Accounting Standards Codification
-Section 55
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477548/944-605-55-15

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 605
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477548/944-605-55-12

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480738/235-10-S50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(f))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480678/235-10-S99-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

+ Details

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481544/470-10-50-6

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The carrying amount as of the balance sheet date for the aggregate of other miscellaneous borrowings owed by the reporting entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

+ Details

Name:	us-gaap_OtherBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_DebtInstrumentAxis=tg_GuangzhouTredegarLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=tg_AmendedABLFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=tg_AdjustedTermSecuredOvernightFinancingRateSOFRMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=tg_TermSecuredOvernightFinancingRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=tg_FixedChargeCoverageRatioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=tg_AmendedABLFacilityIfAverageUsageIsGreaterThanOrEqualTo50Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=tg_AmendedABLFacilityIfAverageUsageIsLessThan50Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

DEBT (Details) ¥ in Millions, $ in Millions		3 Months Ended	9 Months Ended
DEBT (Details) ¥ in Millions, $ in Millions	Jun. 25, 2024 CNY (¥)	Mar. 31, 2025	Sep. 30, 2025 USD ($) Rate	Sep. 30, 2025 CNY (¥) Rate	May 31, 2025 USD ($)	Dec. 31, 2024 USD ($)
Line of Credit Facility [Line Items]
Maximum borrowing capacity after ABL adjustment			$ 125.0		$ 125.0
Remaining borrowing capacity			$ 72.5
Percentage of remaining borrowing capacity \| Rate			58.00%	58.00%
Minimum availability after ABL adjustment \| Rate			20.00%	20.00%
Minimum Availability, Dollar Threshold			$ 20.0
Letters of Credit Outstanding, Amount			$ 3.0			$ 12.0
Guangzhou Tredegar Loan
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.45%
Borrowing \| ¥	¥ 9.5
Mortgage contract maximum value \| ¥				¥ 30.0
Revolving Credit Facility \| Amended ABL Facility
Line of Credit Facility [Line Items]
Commitment fee percentage threshold			50.00%	50.00%
Property, plant, and equipment component threshold, percentage of net orderly liquidation value			60.00%
Property, plant, and equipment component threshold, percentage of borrowing base			30.00%
Amount of eligible cash, cap, percentage of borrowing base			15.00%
Revolving Credit Facility \| Amended ABL Facility \| Adjusted Term Secured Overnight Financing Rate (SOFR)
Line of Credit Facility [Line Items]
Basis spread on variable rate			1.00%
Revolving Credit Facility \| Amended ABL Facility \| Term Secured Overnight Financing Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.10%
Initial floor percentage			0.00%
Revolving Credit Facility \| Amended ABL Facility \| Fixed Charge Coverage Ratio
Line of Credit Facility [Line Items]
Minimum availability before ABL adjustment			0.10	0.10
Fixed charge coverage ratio, monetary availability threshold			$ 10.0
Revolving Credit Facility \| Amended ABL Facility \| Base Rate
Line of Credit Facility [Line Items]
Cash Dominion Period availability			0.125	0.125
Cash dominion period, monetary availability threshold			$ 12.6
Revolving Credit Facility \| Amended ABL Facility If Average Usage Is Greater Than Or Equal To 50%
Line of Credit Facility [Line Items]
Commitment fee percentage		0.40%	0.25%
Revolving Credit Facility \| Amended ABL Facility If Average Usage Is Less Than 50%
Line of Credit Facility [Line Items]
Commitment fee percentage			0.375%