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Retirement Plans And Other Postretirement Benefits (Schedule Of Pension Plan Assets Categorized By Level Within Fair Value Measurement Hierarchy) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Contracts with insurance companies	$ 10,267tg_EstimatedValueOfAssetContractsWithInsuranceCompanies	$ 9,420tg_EstimatedValueOfAssetContractsWithInsuranceCompanies
Total plan assets	229,017us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsCurrentAndNoncurrent	232,705us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsCurrentAndNoncurrent
Large/mid-capitalization equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	31,401us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_LargeMidCapitalizationEquitySecuritiesMember	32,134us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_LargeMidCapitalizationEquitySecuritiesMember
Small-capitalization equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	9,827us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_SmallCapitalizationEquitySecuritiesMember	11,063us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_SmallCapitalizationEquitySecuritiesMember
International and emerging market equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	25,224us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_InternationalAndEmergingMarketEquitySecuritiesMember	27,271us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_InternationalAndEmergingMarketEquitySecuritiesMember
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	33,281us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeSecuritiesMember	32,601us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeSecuritiesMember
Private equity and hedge funds
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	117,276us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_HedgeAndPrivateEquityFundsMember	112,345us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_HedgeAndPrivateEquityFundsMember
Other assets
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	1,741us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_OtherAssetsMember	7,871us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_OtherAssetsMember
Total Plan Assets at Fair Value [Member]
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	218,750us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_TotalPlanAssetsatFairValueMember	223,285us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_TotalPlanAssetsatFairValueMember
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	67,101us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member	82,326us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Quoted Prices in Active Markets for Identical Assets (Level 1) | Large/mid-capitalization equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	31,401us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_LargeMidCapitalizationEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member	32,134us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_LargeMidCapitalizationEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Quoted Prices in Active Markets for Identical Assets (Level 1) | Small-capitalization equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	9,827us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_SmallCapitalizationEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member	11,063us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_SmallCapitalizationEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Quoted Prices in Active Markets for Identical Assets (Level 1) | International and emerging market equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	11,471us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_InternationalAndEmergingMarketEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member	13,488us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_InternationalAndEmergingMarketEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	12,661us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member	17,770us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Quoted Prices in Active Markets for Identical Assets (Level 1) | Private equity and hedge funds
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_HedgeAndPrivateEquityFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_HedgeAndPrivateEquityFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other assets
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	1,741us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member	7,871us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	140,574us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member	132,145us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Other Observable Inputs (Level 2) | Large/mid-capitalization equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_LargeMidCapitalizationEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_LargeMidCapitalizationEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Other Observable Inputs (Level 2) | Small-capitalization equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_SmallCapitalizationEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_SmallCapitalizationEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Other Observable Inputs (Level 2) | International and emerging market equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	13,753us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_InternationalAndEmergingMarketEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member	13,783us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_InternationalAndEmergingMarketEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Other Observable Inputs (Level 2) | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	20,620us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member	14,831us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Other Observable Inputs (Level 2) | Private equity and hedge funds
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	106,201us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_HedgeAndPrivateEquityFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member	103,531us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_HedgeAndPrivateEquityFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Other Observable Inputs (Level 2) | Other assets
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	11,075us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member	8,814us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member
Significant Unobservable Inputs (Level 3) | Large/mid-capitalization equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_LargeMidCapitalizationEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_LargeMidCapitalizationEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member
Significant Unobservable Inputs (Level 3) | Small-capitalization equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_SmallCapitalizationEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_SmallCapitalizationEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member
Significant Unobservable Inputs (Level 3) | International and emerging market equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_InternationalAndEmergingMarketEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_InternationalAndEmergingMarketEquitySecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member
Significant Unobservable Inputs (Level 3) | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member	0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_FixedIncomeSecuritiesMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member
Significant Unobservable Inputs (Level 3) | Private equity and hedge funds
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	11,075us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_HedgeAndPrivateEquityFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member	8,814us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = tg_HedgeAndPrivateEquityFundsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member
Significant Unobservable Inputs (Level 3) | Other assets
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	$ 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member	$ 0us-gaap_DefinedBenefitPlanFairValueOfPlanAssets / us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis = us-gaap_OtherAssetsMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member

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- Definition

Estimated value of asset contracts with insurance companies.

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This represents the entire assets recognized in the balance sheet that are associated with the defined benefit plans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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- Definition

Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

+ References

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