v2.4.1.9

FAIR VALUE MEASUREMENTS AND FINANCIAL INSTRUMENTS (Details 2) | 12 Months Ended |  | 12 Months Ended |  | 12 Months Ended
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Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($) | Dec. 31, 2012 USD ($) | Dec. 31, 2014 Twoo [Member] USD ($) | Dec. 31, 2014 Twoo [Member] EUR (€) | Dec. 31, 2014 Auction rate securities USD ($) | Dec. 31, 2013 Auction rate securities USD ($) | Dec. 31, 2014 Contingent Consideration Arrangement USD ($) | Dec. 31, 2013 Contingent Consideration Arrangement USD ($) | Dec. 31, 2014 Contingent Consideration Without Limit USD ($) | Dec. 31, 2014 Contingent Consideration Liability - Twoo
Changes in assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) |  |  |  |  |  |  |  |  |  |  |
Balance at the beginning of the period, assets |  |  |  |  |  | $ 8,920,000 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue / iaci_FairValueByAssetAndLiabilityClassAxis = us-gaap_AuctionRateSecuritiesMember | $ 8,100,000 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue / iaci_FairValueByAssetAndLiabilityClassAxis = us-gaap_AuctionRateSecuritiesMember |  |  |  |
Included in other comprehensive (loss) income, assets |  |  |  |  |  | (2,850,000)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss / iaci_FairValueByAssetAndLiabilityClassAxis = us-gaap_AuctionRateSecuritiesMember | 820,000 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossIncludedInOtherComprehensiveIncomeLoss / iaci_FairValueByAssetAndLiabilityClassAxis = us-gaap_AuctionRateSecuritiesMember |  |  |  |
Settlements, assets |  |  |  |  |  |  | 0 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements / iaci_FairValueByAssetAndLiabilityClassAxis = us-gaap_AuctionRateSecuritiesMember |  |  |  |
Balance at the end of the period, assets |  |  |  |  |  | 6,070,000 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue / iaci_FairValueByAssetAndLiabilityClassAxis = us-gaap_AuctionRateSecuritiesMember | 8,920,000 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue / iaci_FairValueByAssetAndLiabilityClassAxis = us-gaap_AuctionRateSecuritiesMember |  |  |  |
Changes in liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) |  |  |  |  |  |  |  |  |  |  |
Balance at the beginning of the period, liabilities |  |  |  |  |  |  |  | (45,828,000)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember | (1,909,000)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember |  |
Included in Earnings, liabilities |  |  |  |  |  |  |  | 13,367,000 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember | (343,000)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInEarnings / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember |  |
Included in Other Comprehensive (Loss) Income, liabilities |  |  |  |  |  |  |  | 3,025,000 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInOtherComprehensiveIncome / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember | (2,445,000)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilityGainLossIncludedInOtherComprehensiveIncome / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember |  |
Fair Value Of Contingent Consideration At Date Of Acquisition | 8,800,000 iaci_FairValueOfContingentConsiderationAtDateOfAcquisition | 41,400,000 iaci_FairValueOfContingentConsiderationAtDateOfAcquisition |  |  |  |  |  | 8,813,000 iaci_FairValueOfContingentConsiderationAtDateOfAcquisition / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember | 41,387,000 iaci_FairValueOfContingentConsiderationAtDateOfAcquisition / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember |  |
Settlements, liabilities |  |  |  |  |  |  |  | 8,109,000 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember | 256,000 us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisLiabilitySettlements / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember |  |
Balance at the end of the period, liabilities |  |  |  |  |  |  |  | (30,140,000)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember | (45,828,000)us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationsRecurringBasisLiabilityValue / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember |  |
Auction rate securities |  |  |  |  |  |  |  |  |  |  |
Cost Basis | 159,418,000 us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis |  |  |  |  | 10,000,000 us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis / iaci_FairValueByAssetAndLiabilityClassAxis = us-gaap_AuctionRateSecuritiesMember | 10,000,000 us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis / iaci_FairValueByAssetAndLiabilityClassAxis = us-gaap_AuctionRateSecuritiesMember |  |  |  |
Gross unrealized loss | 1,387,000 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax | 4,784,000 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax |  |  |  | 3,900,000 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax / iaci_FairValueByAssetAndLiabilityClassAxis = us-gaap_AuctionRateSecuritiesMember | 1,100,000 us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax / iaci_FairValueByAssetAndLiabilityClassAxis = us-gaap_AuctionRateSecuritiesMember |  |  |  |
Contingent consideration arrangment |  |  |  |  |  |  |  |  |  |  |
Number of contingent consideration arrangements related to business acquisitions | 5 iaci_NumberofContingentConsiderationArrangementsRelatedtoBusinessAcquisitions |  |  |  |  |  |  |  |  |  |
Number of contingent consideration arrangements with payment limit | 4 iaci_NumberofContingentConsiderationArrangementswithPaymentLimit |  |  |  |  |  |  |  |  |  |
Business Acquisition Contingent Consideration Maximum Amount At Balance Sheet Date |  |  |  |  |  |  |  | 166,900,000 iaci_BusinessAcquisitionContingentConsiderationMaximumAmountAtBalanceSheetDate / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember |  |  |
Business Acquisition Contingent Consideration Fair Value at Balance Sheet Date With A Maximum Limit |  |  |  |  |  |  |  | 29,500,000 iaci_BusinessAcquisitionContingentConsiderationFairValueatBalanceSheetDateWithAMaximumLimit / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationArrangementMember |  |  |
Fair value of one contingent consideration arrangements without a maximum limit |  |  |  |  |  |  |  |  |  | 700,000 iaci_BusinessAcquisitionContingentConsiderationFairvalueatBalanceSheetDateWithoutaLimit / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationWithoutLimitMember |
Acquisition-related contingent consideration payments | 8,109,000 iaci_BusinessCombinationContingentConsiderationPaymentFinancing | 256,000 iaci_BusinessCombinationContingentConsiderationPaymentFinancing | 10,781,000 iaci_BusinessCombinationContingentConsiderationPaymentFinancing | 7,400,000 iaci_BusinessCombinationContingentConsiderationPaymentFinancing / us-gaap_BusinessAcquisitionAxis = iaci_TwooMember |  |  |  |  |  |  |
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High |  |  |  | 94,900,000 us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh / us-gaap_BusinessAcquisitionAxis = iaci_TwooMember | 77,900,000 us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh / us-gaap_BusinessAcquisitionAxis = iaci_TwooMember |  |  |  |  |  |
Fair Value, Discount Rate |  |  |  |  |  |  |  |  |  |  | 15.00%us-gaap_FairValueInputsDiscountRate / iaci_FairValueByAssetAndLiabilityClassAxis = iaci_ContingentConsiderationLiabilityTwooMember
Contingent Consideration, Current |  |  |  | 10,700,000 iaci_BusinessAcquisitionContingentConsiderationFairValueAtBalanceSheetDateCurrent / us-gaap_BusinessAcquisitionAxis = iaci_TwooMember |  |  |  |  |  |  |
Contingent Consideration, Noncurrent |  |  |  | $ 19,600,000 iaci_BusinessAcquisitionContingentConsiderationFairValueAtBalanceSheetNoncurrent / us-gaap_BusinessAcquisitionAxis = iaci_TwooMember |  |  |  |  |  |  |

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- Definition Current portion of the fair value as of the Balance Sheet date of potential payments under the contingent consideration arrangement. + References No definition available. + Details
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- Definition Fair Value, as of the Balance Sheet date, of potential cash payments under the contingent consideration arrangement with a maximum amount limit. + References No definition available. + Details
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- Definition Maximum amount of potential cash payments under the contingent consideration arrangement as of the Balance Sheet date. + References No definition available. + Details
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- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 + Details
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- Definition This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 + Details
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- Definition For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 + Details
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- Definition Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258 + Details
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- Definition Amount of gain (loss) recognized in other comprehensive income (loss) for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1a) -URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258 + Details
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- Definition Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258 + Details
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- Definition Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258 + Details
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- Definition Amount of settlements of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258 + Details
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