v2.4.1.9
Compensation Plans and Programs (Details) (USD $)
3 Months Ended 12 Months Ended
Dec. 31, 2013
Mar. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award and Other Compensation Benefits [Line Items] [Line Items]          
Stock Issued During Period, Shares, Share-based Compensation, Forfeited     (312,000)us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationForfeited    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value     $ 45.01us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period     (258,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number 1,632,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber   1,902,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber 1,632,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber  
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price     $ 30.69us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice    
Equity Available for Grant [Roll Forward]          
Equity Instruments Available for Grant as of December 31, 2010     2,005,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant    
RSUs granted     840,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod    
Options Expired and RSUs cancelled     420,000idcc_Sharebasedcompensationarrangementbysharebasedpaymentawardforfeituresandexpirationsinperiod    
Equity Instruments Available for Grant as of December 31, 2011 2,005,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant   1,445,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant 2,005,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant  
Number of Shares Authorized     3,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized    
Minimum Exercise Price Per Share Options     100.00%idcc_MinimumExercisePricePerShareOptions    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term     15 years 1 month 15 days    
Stock Options, Outstanding [Roll Forward]          
Outstanding Options, as of December 31, 2010     245,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period     (28,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriod    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period     (21,000)us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised    
Outstanding Options, as of December 31, 2011 245,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber   336,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber 245,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber  
Weighted Average Excercise Price, as of December 31, 2010     $ 22.61us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice    
Cancellations in Period, Weighted Average Exercise Price     $ 38.78us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresAndExpirationsInPeriodWeightedAverageExercisePrice    
Exercises in Period, Weighted Average Exercise Price     $ 20.13us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice    
Weighted Average Exercise Price, as of December 31, 2011 $ 22.61us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice   $ 24.90us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice $ 22.61us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit     $ 8.00us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit    
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit     $ 11.63us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeUpperRangeLimit    
Intrinsic Value of Stock Options Exercised During Period     $ 300,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue $ 1,000,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue $ 2,800,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Stock Options, Outstanding, Intrinsic Value     9,400,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue    
Proceeds from Stock Options Exercised     402,000us-gaap_ProceedsFromStockOptionsExercised 1,032,000us-gaap_ProceedsFromStockOptionsExercised 2,111,000us-gaap_ProceedsFromStockOptionsExercised
Excess Tax Benefit from Share-based Compensation, Financing Activities     0us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities 815,000us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities 898,000us-gaap_ExcessTaxBenefitFromShareBasedCompensationFinancingActivities
Vested in Period, Total Fair Value     7,700,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue 6,500,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue 12,900,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options 300,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions   300,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions 300,000us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeNumberOfOutstandingOptions  
Proceeds From Stock Options If Exercised 1,700,000idcc_ProceedsFromStockOptionsIfExercised   8,400,000idcc_ProceedsFromStockOptionsIfExercised 1,700,000idcc_ProceedsFromStockOptionsIfExercised  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]          
RSUs granted     (840,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod    
RSUs, Grants in Period, Weighted Average Grant Date Fair Value     $ 34.42us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue $ 42.34us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue $ 39.35us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
RSUs, Vested in Period, Weighted Average Grant Date Fair Value     $ 31.29us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue    
Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights     100,000us-gaap_IncrementalCommonSharesAttributableToParticipatingNonvestedSharesWithNonForfeitableDividendRights    
Share-based Compensation     18,494,000us-gaap_ShareBasedCompensation 15,940,000us-gaap_ShareBasedCompensation 6,495,000us-gaap_ShareBasedCompensation
Other than Temporary Impairment Losses, Investments 15,000,000us-gaap_ImpairmentOfInvestments 6,700,000us-gaap_ImpairmentOfInvestments 559,000us-gaap_ImpairmentOfInvestments 21,720,000us-gaap_ImpairmentOfInvestments 0us-gaap_ImpairmentOfInvestments
Other Postretirement Benefit Expense     1,000,000us-gaap_OtherPostretirementBenefitExpense 1,000,000us-gaap_OtherPostretirementBenefitExpense 1,000,000us-gaap_OtherPostretirementBenefitExpense
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value $ 42.04us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue   $ 35.73us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue $ 42.04us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedWeightedAverageGrantDateFairValue  
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross     (140,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross    
Stock Options Outstaning which have an Indefinite Contractual Term [Member]          
Stock Options, Outstanding [Roll Forward]          
Outstanding Options, as of December 31, 2011     100,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_AwardTypeAxis
= idcc_StockOptionsOutstaningWhichHaveIndefiniteContractualTermMember
   
Cash from stock options [Member]          
Stock Options, Outstanding [Roll Forward]          
Proceeds from Stock Options Exercised     400,000us-gaap_ProceedsFromStockOptionsExercised
/ us-gaap_AwardTypeAxis
= idcc_CashFromStockOptionsMember
   
Restricted Stock Units (RSU) and/or Restricted Stock [Member]          
Equity Available for Grant [Roll Forward]          
RSUs granted     600,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= idcc_RestrictedStockUnitsRsuAndOrRestrictedStockMember
900,000us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= idcc_RestrictedStockUnitsRsuAndOrRestrictedStockMember
 
Stock Options, Outstanding [Roll Forward]          
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures     100,000us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures
/ us-gaap_AwardTypeAxis
= idcc_RestrictedStockUnitsRsuAndOrRestrictedStockMember
   
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized $ 11,200,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= idcc_RestrictedStockUnitsRsuAndOrRestrictedStockMember
  $ 17,900,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= idcc_RestrictedStockUnitsRsuAndOrRestrictedStockMember
$ 11,200,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
/ us-gaap_AwardTypeAxis
= idcc_RestrictedStockUnitsRsuAndOrRestrictedStockMember
 
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]          
RSUs granted     (600,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= idcc_RestrictedStockUnitsRsuAndOrRestrictedStockMember
(900,000)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= idcc_RestrictedStockUnitsRsuAndOrRestrictedStockMember