Quarterly report pursuant to Section 13 or 15(d)

Assets and Liabilities Measured at Fair Value (Details)

v2.4.1.9
Assets and Liabilities Measured at Fair Value (Details) (USD $)
 3 Months Ended 0 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Apr. 01, 2015
Dec. 31, 2014
Mar. 27, 2015
Assets and Liabilities Measured at Fair Value          
Short-term marketable securities $ 9,004,000us-gaap_MarketableSecuritiesCurrent     $ 9,001,000us-gaap_MarketableSecuritiesCurrent  
Investments, at fair value 355,202,000us-gaap_AvailableForSaleSecuritiesNoncurrent     360,762,000us-gaap_AvailableForSaleSecuritiesNoncurrent  
Payments from settlements of financial instruments 30,158,000us-gaap_PaymentsForDerivativeInstrumentFinancingActivities 32,415,000us-gaap_PaymentsForDerivativeInstrumentFinancingActivities      
Revolving Credit Facility          
Assets and Liabilities Measured at Fair Value          
Line of Credit Facility, Maximum Borrowing Capacity         234,000,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_DebtInstrumentAxis
= us-gaap_RevolvingCreditFacilityMember
Time Warner          
Assets and Liabilities Measured at Fair Value          
Investments, at fair value 354,460,000us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lbrda_TimeWarnerCableIncMember 		    359,615,000us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lbrda_TimeWarnerCableIncMember 		 
Cashless Collar | Time Warner          
Assets and Liabilities Measured at Fair Value          
Derivative share amount hedged         1,700,000lbrda_DerivativeAmountOfHedgedItemShares
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Cashless Collar | Put Option | Time Warner          
Assets and Liabilities Measured at Fair Value          
Derivative, Price Risk Option Strike Price         136.80us-gaap_DerivativePriceRiskOptionStrikePrice
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= lbrda_TimeWarnerCableIncMember
Cashless Collar | Call Option | Time Warner          
Assets and Liabilities Measured at Fair Value          
Derivative, Price Risk Option Strike Price         161.62us-gaap_DerivativePriceRiskOptionStrikePrice
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= lbrda_TimeWarnerCableIncMember
Total | Recurring          
Assets and Liabilities Measured at Fair Value          
Cash and cash equivalents 754,467,000us-gaap_CashAndCashEquivalentsFairValueDisclosure
/ us-gaap_FairValueByMeasurementBasisAxis
= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember 		    36,002,000us-gaap_CashAndCashEquivalentsFairValueDisclosure
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= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
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Short-term marketable securities 9,004,000us-gaap_MarketableSecuritiesCurrent
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= us-gaap_EstimateOfFairValueFairValueDisclosureMember
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember 		    9,001,000us-gaap_MarketableSecuritiesCurrent
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/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember 		 
Total | Written call option | Recurring | Time Warner          
Assets and Liabilities Measured at Fair Value          
Derivative liabilities, at fair value (71,530,000)us-gaap_DerivativeLiabilities
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/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lbrda_TimeWarnerCableIncMember 		    (75,356,000)us-gaap_DerivativeLiabilities
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= lbrda_TimeWarnerCableIncMember 		 
Available for sale securities | Total | Recurring          
Assets and Liabilities Measured at Fair Value          
Investments, at fair value 355,202,000us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_FairValueByMeasurementBasisAxis
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/ us-gaap_FairValueByMeasurementFrequencyAxis
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/ us-gaap_InvestmentSecondaryCategorizationAxis
= us-gaap_AvailableforsaleSecuritiesMember 		    360,762,000us-gaap_AvailableForSaleSecuritiesNoncurrent
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Expiration Date February 2015 | Written call option | Time Warner          
Assets and Liabilities Measured at Fair Value          
Class of Warrant or Right, Outstanding       625,000us-gaap_ClassOfWarrantOrRightOutstanding
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/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lbrda_TimeWarnerCableIncMember 		 
Derivative, Price Risk Option Strike Price       92.02us-gaap_DerivativePriceRiskOptionStrikePrice
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= lbrda_WrittenCallOptionMember
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= lbrda_TimeWarnerCableIncMember 		 
Expiration Date February 2016 [member] | Written call option | Time Warner          
Assets and Liabilities Measured at Fair Value          
Class of Warrant or Right, Outstanding 625,000us-gaap_ClassOfWarrantOrRightOutstanding
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Derivative, Price Risk Option Strike Price 100.39us-gaap_DerivativePriceRiskOptionStrikePrice
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= lbrda_WrittenCallOptionMember
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= lbrda_TimeWarnerCableIncMember 		       
Expiration Date May 2015 | Written call option | Time Warner          
Assets and Liabilities Measured at Fair Value          
Class of Warrant or Right, Outstanding 625,000us-gaap_ClassOfWarrantOrRightOutstanding
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= lbrda_WrittenCallOptionMember
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= lbrda_ExpirationDateMay2015Member
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lbrda_TimeWarnerCableIncMember 		    625,000us-gaap_ClassOfWarrantOrRightOutstanding
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= lbrda_WrittenCallOptionMember
/ us-gaap_InvestmentSecondaryCategorizationAxis
= lbrda_ExpirationDateMay2015Member
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= lbrda_TimeWarnerCableIncMember 		 
Derivative, Price Risk Option Strike Price 90.84us-gaap_DerivativePriceRiskOptionStrikePrice
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= lbrda_TimeWarnerCableIncMember 		       
Payments from settlements of financial instruments     36,700,000us-gaap_PaymentsForDerivativeInstrumentFinancingActivities
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= lbrda_WrittenCallOptionMember
/ us-gaap_InvestmentSecondaryCategorizationAxis
= lbrda_ExpirationDateMay2015Member
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lbrda_TimeWarnerCableIncMember 		   
Quoted prices in active markets for identical assets (Level 1) | Recurring          
Assets and Liabilities Measured at Fair Value          
Cash and cash equivalents 754,467,000us-gaap_CashAndCashEquivalentsFairValueDisclosure
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/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember 		    36,002,000us-gaap_CashAndCashEquivalentsFairValueDisclosure
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= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
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Short-term marketable securities 9,004,000us-gaap_MarketableSecuritiesCurrent
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= us-gaap_FairValueInputsLevel1Member
/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember 		    9,001,000us-gaap_MarketableSecuritiesCurrent
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Quoted prices in active markets for identical assets (Level 1) | Available for sale securities | Recurring          
Assets and Liabilities Measured at Fair Value          
Investments, at fair value 355,202,000us-gaap_AvailableForSaleSecuritiesNoncurrent
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/ us-gaap_FairValueByMeasurementFrequencyAxis
= us-gaap_FairValueMeasurementsRecurringMember
/ us-gaap_InvestmentSecondaryCategorizationAxis
= us-gaap_AvailableforsaleSecuritiesMember 		    360,762,000us-gaap_AvailableForSaleSecuritiesNoncurrent
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Level 2 | Written call option | Recurring | Time Warner          
Assets and Liabilities Measured at Fair Value          
Derivative liabilities, at fair value $ (71,530,000)us-gaap_DerivativeLiabilities
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= lbrda_WrittenCallOptionMember
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= us-gaap_FairValueInputsLevel2Member
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= us-gaap_FairValueMeasurementsRecurringMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lbrda_TimeWarnerCableIncMember 		    $ (75,356,000)us-gaap_DerivativeLiabilities
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= lbrda_WrittenCallOptionMember
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Minimum          
Level 2 input          
Volatility 21.40%us-gaap_FairValueAssumptionsExpectedVolatilityRate
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Interest rate 0.41%us-gaap_FairValueAssumptionsRiskFreeInterestRate
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Dividend yield 0.00%us-gaap_FairValueAssumptionsExpectedDividendRate
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Maximum          
Level 2 input          
Volatility 26.48%us-gaap_FairValueAssumptionsExpectedVolatilityRate
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Interest rate 0.56%us-gaap_FairValueAssumptionsRiskFreeInterestRate
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Dividend yield 0.24%us-gaap_FairValueAssumptionsExpectedDividendRate
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