XML 142 R101.htm IDEA: XBRL DOCUMENT
v3.20.1

Retirement Plans And Other Postretirement Benefits (Schedule Of Fair Value Measurements Of Plan Assets Using Significant Unobservable Inputs (Level 3), Reconciliation Of Balances) (Details) $ in Thousands | Dec. 31, 2019 USD ($)
--- | ---
Significant Unobservable Inputs (Level 3) |
Defined Benefit Plan Disclosure [Line Items] |
Estimated Value Of Asset Contracts With Insurance Companies | $ 8,840

X
- Definition Estimated value of asset contracts with insurance companies. + References No definition available. + Details
Name: | tg_EstimatedValueOfAssetContractsWithInsuranceCompanies
Namespace Prefix: | tg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- 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 No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |