XML 42 R40.htm IDEA: XBRL DOCUMENT v2.4.1.9
Investments (Narrative) (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 12 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2013
Dec. 31, 2014
Dec. 31, 2008
Aug. 31, 2007
kaleo            
Total cash invested in private company         $ 7.5us-gaap_TaxBasisOfInvestmentsCostForIncomeTaxPurposes
/ dei_LegalEntityAxis
= tg_KaleoMember
  
Ownership interest percentage 20.00%us-gaap_VariableInterestEntityOwnershipPercentage
/ dei_LegalEntityAxis
= tg_KaleoMember
         
Carrying value 39.1us-gaap_InvestmentOwnedAtFairValue
/ dei_LegalEntityAxis
= tg_KaleoMember
    39.1us-gaap_InvestmentOwnedAtFairValue
/ dei_LegalEntityAxis
= tg_KaleoMember
   
Weighted average cost of capital 45.00%us-gaap_FairValueInputsDiscountRate
/ dei_LegalEntityAxis
= tg_KaleoMember
45.00%us-gaap_FairValueInputsDiscountRate
/ dei_LegalEntityAxis
= tg_KaleoMember
45.00%us-gaap_FairValueInputsDiscountRate
/ dei_LegalEntityAxis
= tg_KaleoMember
     
Basis point decrease of weighted average cost of capital assumption 5.00%tg_PointDecreaseOfWeightedAverageCostOfCapitalAssumption
/ dei_LegalEntityAxis
= tg_KaleoMember
         
Basis point increase of weighted average cost of capital assumption 5.00%tg_PointIncreaseOfWeightedAverageCostOfCapitalAssumption
/ dei_LegalEntityAxis
= tg_KaleoMember
         
Increase in fair value from five hundred point decrease in weighted average cost of capital assumption 7tg_IncreaseInFairValueFromFiveHundredPointDecreaseInWeightedAverageCostOfCapitalAssumption
/ dei_LegalEntityAxis
= tg_KaleoMember
         
Decrease in fair value from five hundred point increase in weighted average cost of capital assumption 5tg_DecreaseInFairValueFromFiveHundredPointIncreaseInWeightedAverageCostOfCapitalAssumption
/ dei_LegalEntityAxis
= tg_KaleoMember
         
Harbinger Fund            
Cost-method investment, OTTI 0us-gaap_CostmethodInvestmentsOtherThanTemporaryImpairment
/ dei_LegalEntityAxis
= tg_HarbingerCapitalPartnersSpecialSituationsFundLPMember
0.2us-gaap_CostmethodInvestmentsOtherThanTemporaryImpairment
/ dei_LegalEntityAxis
= tg_HarbingerCapitalPartnersSpecialSituationsFundLPMember
       
Harbinger Fund            
Cost Method Investments 1.8us-gaap_CostMethodInvestments
/ us-gaap_StatementBusinessSegmentsAxis
= tg_HarbingerCapitalPartnersSpecialSituationsFundLPMember
    1.8us-gaap_CostMethodInvestments
/ us-gaap_StatementBusinessSegmentsAxis
= tg_HarbingerCapitalPartnersSpecialSituationsFundLPMember
   
Alleghany and Bath County, Virginia [Member]            
Cost Method Investments $ 2.6us-gaap_CostMethodInvestments
/ dei_EntityByLocationAxis
= tg_AlleghanyandBathCountyVirginiaMember
    $ 2.6us-gaap_CostMethodInvestments
/ dei_EntityByLocationAxis
= tg_AlleghanyandBathCountyVirginiaMember