Granted (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Accumulated Other Comprehensive Loss Accumulated Other Comprehensive Income (Loss) [Roll Forward] Accumulated Other Comprehensive Income (Loss) [Roll Forward] Non-deductible expenses Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount Stock options outstanding aggregate intrinsic value Balance at end of period Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Related Party [Axis] Related Party [Axis] Deferred income taxes Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] 2028 Long-term Debt, maturity, Year Eight Long-term Debt, maturity, Year Eight Noncontrolling Interest [Table] Noncontrolling Interest [Table] Condensed Income Statement [Table] Condensed Income Statement [Table] Schedule of Capital Expenditures by Segment Schedule of Capital Expenditures by Segment [Table Text Block] Schedule of Capital Expenditures by Segment [Table Text Block] Proceeds from maturities of marketable debt securities Proceeds from Sale and Maturity of Marketable Securities Deferred tax adjustment for enacted changes in tax laws and rates Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Schedule of Commercial Commitments Outstanding Other Commitments [Table Text Block] Statistical Measurement [Domain] Statistical Measurement [Domain] LIABILITIES AND SHAREHOLDERS' AND PARENT'S EQUITY Liabilities and Equity [Abstract] Share-based Compensation Arrangement by Share-based Payment Award Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Security Exchange Name Security Exchange Name IAC IAC [Member] IAC BENEFIT PLANS Compensation and Employee Benefit Plans [Text Block] Selling and marketing expense Selling and Marketing Expense [Member] Schedule of Long-lived Assets by Geographic Areas Long-lived Assets by Geographic Areas [Table Text Block] Total current liabilities Liabilities, Current Diluted earnings (loss) per share attributable to ANGI Homeservices Inc. shareholders (USD per share) Business Acquisition, Pro Forma Earnings Per Share, Diluted Change in foreign currency translation adjustment attributable to noncontrolling interests Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest Performance Shares Performance Shares [Member] Balance at beginning of the period (USD per share) Balance at end of the period (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Variable Rate [Domain] Variable Rate [Domain] ASSETS Assets: Assets [Abstract] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Investment, Name [Axis] Investment, Name [Axis] Accounting Policies [Abstract] Accounting Policies [Abstract] Issuance of common stock pursuant to stock-based awards, net of withholding taxes Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture Cash paid for amounts included in the measurement of lease liabilities Operating Lease, Payments Number of plaintiffs who filed a discontinuance of claims Loss Contingency, Number of Plaintiffs who Filed a Discontinuance of Claims Loss Contingency, Number of Plaintiffs who Filed a Discontinuance of Claims Transaction exchange ratio Share-based Compensation Arrangement by Share-based Payment Award, Options, Transaction Exchange Ratio Share-based Compensation Arrangement by Share-based Payment Award, Options, Transaction Exchange Ratio Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] ACCUMULATED OTHER COMPREHENSIVE LOSS Comprehensive Income (Loss) Note [Text Block] 2023 Long-Term Debt, Maturity, Year Three Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Estimated weighted-average useful life (in months) Useful Life (Years) Acquired Finite-lived Intangible Assets, Weighted Average Useful Life 2021 Lessee, Operating Lease, Liability, to be Paid, Year One Class B Common Stock Class B Convertible Common Stock Class A Common Stock, Secondary Raise Common Class B [Member] Balance at beginning of period (shares) Balance at end of period (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Tax provision (benefit) on accumulated other comprehensive loss AOCI Tax, Attributable to Parent 2024 Lessee, Operating Lease, Liability, to be Paid, Year Four Other Temporary Equity, Other Changes Schedule of Financial Instruments Measured at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Unrecognized compensation cost, net of estimated forfeitures Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Proceeds from issuance of related-party debt Proceeds from Related Party Debt State Current State and Local Tax Expense (Benefit) Tax credit carryforwards Tax Credit Carryforward, Amount Exercise price range, lower limit (USD per share) Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit Other comprehensive income (loss), net of income taxes: Other Comprehensive Income (Loss), Net of Tax [Abstract] Common stock, par value (USD per share) Common Stock, Par or Stated Value Per Share Debt Instrument, Covenant, Leverage Ratio, Maximum Debt Instrument, Covenant, Leverage Ratio, Maximum Debt Instrument, Covenant, Leverage Ratio, Maximum Other long-term liabilities Other Liabilities, Noncurrent Continuing Operations or Discontinued Operations [Axis] Operating Activities [Axis] Document Information [Table] Document Information [Table] Deferred tax valuation allowance SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] Effect of exchange rate changes on cash and cash equivalents and restricted cash Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Other Other Assets, Miscellaneous, Current Denominator: Basic Weighted Average Number of Shares Outstanding, Basic [Abstract] Net earnings Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Service professional relationships Contractor and Service Professional Relationships and Other [Member] Contractor and Service Professional Relationships and Other [Member] Concentration risk (as a percent) Concentration Risk, Percentage VALUATION AND QUALIFYING ACCOUNTS SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items] Limited Liability Company Limited Liability Company [Member] Sale of Equity Capital Sale of Equity Capital [Member] Sale of Equity Capital Statement [Line Items] Statement [Line Items] Impairment of equity securities without readily determinable fair value Equity Securities without Readily Determinable Fair Value, Impairment Loss, Cumulative Amount RSA Agreement RSA Agreement [Member] RSA Agreement Class of Stock [Domain] Class of Stock [Domain] Term of debt instrument (years) Debt Instrument, Term Measurement Input Type [Domain] Measurement Input Type [Domain] Statement [Table] Statement [Table] Write-offs charged against the allowance Accounts Receivable, Allowance for Credit Loss, Writeoff Statistical Measurement [Axis] Statistical Measurement [Axis] Other current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other Interest income Interest Income, Other Lease payments for leases signed but not yet commenced Lessee, Operating Lease, Lease Not yet Commenced, Amount Lessee, Operating Lease, Lease Not yet Commenced, Amount Investments in Debt Securities Marketable Securities, Policy [Policy Text Block] Entity Small Business Entity Small Business Number of shares issued in sale of equity capital (in shares) Sale of Stock, Number of Shares Issued in Transaction Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Prepaid expenses Prepaid Expense, Current Cost of revenue (exclusive of depreciation shown separately below) Cost of revenue Cost of Revenue Amendment Flag Amendment Flag Denominator: Diluted Weighted Average Number of Shares Outstanding, Diluted [Abstract] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Balance at beginning of period Balance at end of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Unrecognized tax benefits, income tax penalties and interest accrued Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Tinder Optionholder Litigation Tinder Optionholder Litigation [Member] Tinder Optionholder Litigation [Member] Corporate Corporate, Non-Segment [Member] Other Other Accrued Liabilities, Current Shares available for grant (shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Capitalized software and computer equipment Computer Equipment and Capitalized Software [Member] Represents the information pertaining to computer equipment and capitalized software. Principal payments on related-party debt Repayments of Related Party Debt Adjustment of noncontrolling interests to fair value Adjustment of Redeemable Noncontrolling Interest to Fair Value Adjustment of Redeemable Noncontrolling Interest to Fair Value Income tax expense (benefit) related to operating loss carryforwards recorded as reduction to goodwill Income Tax Expense (Benefit) Related to Operating Loss Carryforwards Recorded as Reduction to Goodwill Income Tax Expense (Benefit) Related to Operating Loss Carryforwards Recorded as Reduction to Goodwill Financial Instruments [Domain] Financial Instruments [Domain] Schedule of Carrying Value and the Fair Value of Financial Instruments Measured at Fair Value Only for Disclosure Purposes Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block] Accounting for Investments in Equity Securities Equity Method Investments [Policy Text Block] Period Three Debt Instrument, Redemption, Period Three [Member] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Available-for-sale marketable debt securities in a continuous unrealized loss position for longer than twelve months Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer Repayments of principal, final payment Long-term Debt, Maturities, Repayments of Principal, Final Payment Long-term Debt, Maturities, Repayments of Principal, Final Payment Redeemable Noncontrolling Interests Redeemable Noncontrolling Interest [Policy Text Block] This element represents the entity's accounting policies for redeemable noncontrolling interests. HomeAdvisor HomeAdvisor [Member] HomeAdvisor - is the operator of the largest global home services marketplace, connecting homeowners with service professionals for home repair, maintenance and improvement projects. SUBSEQUENT EVENTS Subsequent Events [Text Block] Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table] Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table] Period of payment due from customers for accounts receivable Accounts Receivable, Period of Payment Due Accounts Receivable, Period of Payment Due Employee Matters Agreement Employee Matters Agreement [Member] Employee Matters Agreement [Member] Income taxes payable Accrued Income Taxes, Noncurrent Dilutive securities (shares) Weighted Average Number Diluted Shares Outstanding Adjustment Property, Plant and Equipment, Type [Axis] Long-Lived Tangible Asset [Axis] Balance at beginning of period Balance at end of period SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount Allowance and reserves of accounts receivable Accounts Receivable, Allowance for Credit Loss, Current Income Statement Location [Domain] Income Statement Location [Domain] Research credit Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount 2022 Lessee, Operating Lease, Liability, to be Paid, Year Two Other Commitments Other Commitments [Line Items] State Tax Authority State and Local Jurisdiction [Member] Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Schedule of Lease Cost and Other Information Lease, Cost [Table Text Block] 2023 Lessee, Operating Lease, Liability, to be Paid, Year Three Other non-current assets Other Assets, Noncurrent Plan Name [Axis] Plan Name [Axis] Cash equivalents: Cash and Cash Equivalents, Fair Value Disclosure TOTAL ASSETS Assets RELATED PARTY TRANSACTIONS Related Party Transactions Disclosure [Text Block] Impairment charges on indefinite-lived intangible assets Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill) Exercise Price Range [Domain] Exercise Price Range [Domain] Memberships Memberships [Member] Memberships [Member] Other comprehensive loss, net of income tax Other Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Nonredeemable Noncontrolling Interest, Total Other Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Nonredeemable Noncontrolling Interest, Total Equity instruments other than options, outstanding (shares) Balance at beginning of the period (shares) Balance at end of the period (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Retirement Plan Sponsor Location [Axis] Retirement Plan Sponsor Location [Axis] Old IAC Old IAC [Member] Old IAC Expected costs from transactions with related party Related Party Transaction, Expected Costs from Transactions with Related Party Related Party Transaction, Expected Costs from Transactions with Related Party Subsequent Event Type [Axis] Subsequent Event Type [Axis] Short-term investments Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Short-term Investments Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Short-term Investments Investments, Debt and Equity Securities [Abstract] Cost of revenue Cost of sales Cost of Sales [Member] Certain Risks and Concentration Services Agreement with Google (the "Services Agreement") Concentration Risk, Credit Risk, Policy [Policy Text Block] Adjustment of redeemable noncontrolling interests to fair value Temporary Equity, Accretion to Redemption Value Stock authorized for repurchase (shares) Stock Repurchase Program, Number of Shares Authorized to be Repurchased Weighted-average exercise price (USD per share) Share-based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price Unrealized gains, net, on equity securities held Equity Securities, FV-NI, Unrealized Gain (Loss) Cash and cash equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Adjustment to increase (decrease) in revenues Business Acquisition, Pro Forma Information, Adjustment To Increase (Decrease) Revenues Business Acquisition, Pro Forma Information, Adjustment To Increase (Decrease) Revenues Damages sought Loss Contingency, Damages Sought, Value Less: Interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Angie's List Merger Agreement Angie's List Transaction Agreement [Member] Angie's List Transaction Agreement [Member] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Quoted Market Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] One-Time Acquisition-related Costs Acquisition-related Costs [Member] Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Decrease in valuation allowance Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount Interest income, net Interest Income (Expense), Net Additional Paid-in Capital Additional Paid-in Capital [Member] MGM MGM [Member] MGM [Member] Schedule of Other (Expense) Income, Net Schedule of Other Nonoperating Income (Expense) [Table Text Block] Nonrecurring Adjustment [Domain] Nonrecurring Adjustment [Domain] Asset Class [Axis] Asset Class [Axis] Balance at beginning of period (shares) Balance at end of period (shares) Shares, Issued Fair Value Measurements Fair Value of Financial Instruments, Policy [Policy Text Block] Distributions to and purchases of noncontrolling interests Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Schedule of Other Current Assets Schedule of Other Current Assets [Table Text Block] Equity method investment Equity Method Investments Common stock outstanding (shares) Common Stock, Shares, Outstanding Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Interest income from related party (less than) Interest Income, Related Party Felix Felix [Member] Felix [Member] Revolving Credit Facility Revolving Credit Facility [Member] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Earnings (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Fair value of contingent consideration at date of acquisition Fair Value Of Contingent Consideration At Date Of Acquisition Fair Value Of Contingent Consideration At Date Of Acquisition Capitalized downloadable search toolbar costs, net Capitalize Access Fees, Current Represents capitalized costs associated with certain distribution arrangements that require a fee per access point delivered. Balance at beginning of period (USD per share) Balance at end of period (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Common stock authorized (shares) Common Stock, Shares Authorized Proportion of voting interests acquired (as a percent) Business Acquisition, Percentage of Voting Interests Acquired Building, capitalized software, leasehold improvements and equipment Property, Plant and Equipment, Gross Schedule of Revenue by Geographic Areas Revenue from External Customers by Geographic Areas [Table Text Block] Cash received from stock option exercises Proceeds from Stock Options Exercised Federal Deferred Federal Income Tax Expense (Benefit) Schedule of Reconciliation of Adjusted EBITDA to Operating Income (Loss) Schedule of reconciliation of Adjusted EBITDA to operating income [Table Text Block] Tabular disclosure of the reconciliation of Adjusted EBITDA to operating income [Table Text Block] Indefinite-lived Intangible Assets Indefinite-lived Intangible Assets [Member] Schedule of Segment Reporting Information Schedule of Segment Reporting Information, by Segment [Table Text Block] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] Income Statement [Abstract] Income Statement [Abstract] Accumulated Other Comprehensive (Loss) Income Accumulated Other Comprehensive (Loss) Income AOCI Attributable to Parent [Member] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Prepaid debt principal payments Prepaid Debt Principal Payments Prepaid Debt Principal Payments Voting interest (as a percent) Noncontrolling Interest, Voting Rights Percentage by Parent Noncontrolling Interest, Voting Rights Percentage by Parent Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Membership Subscription Marketplace, Membership Subscription [Member] Marketplace, Membership Subscription [Member] Unamortized original issue discount and debt issuance costs Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Accounting Estimates Use of Estimates, Policy [Policy Text Block] AOCI Including Portion Attributable to Noncontrolling Interest AOCI Including Portion Attributable to Noncontrolling Interest [Member] Income Tax Authority [Domain] Income Tax Authority [Domain] Market-Based Stock Units Market-Based Stock Units [Member] Market-Based Stock Units [Member] Software and software development costs Software and Software Development Costs [Member] Invested capital Other Additional Capital Numerator: Basic Net Income (Loss) Available to Common Stockholders, Basic [Abstract] Accumulated Foreign Currency Adjustment Attributable to Noncontrolling Interest Accumulated Foreign Currency Adjustment Attributable to Noncontrolling Interest [Member] Scenario [Domain] Scenario [Domain] Capital expenditures Capital expenditures: Payments to Acquire Property, Plant, and Equipment Consolidation Items [Domain] Consolidation Items [Domain] LONG-TERM DEBT Long-term Debt [Text Block] Contingent consideration arrangement Contingent consideration arrangement Business Combination, Contingent Consideration, Liability GOODWILL AND INTANGIBLE ASSETS Goodwill and Intangible Assets Disclosure [Text Block] Loss contingency accrual Loss Contingency Accrual Provider relationships Customer lists and user base Customer Lists [Member] Earnings (loss) before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Adjustments to Carrying Value of Non-Marketable Equity Securities [Abstract] Equity Securities, FV-NI, Gain (Loss) [Abstract] Goodwill, impaired, accumulated impairment loss Goodwill, Impaired, Accumulated Impairment Loss Total cash provided (used) Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Entity [Domain] Entity [Domain] Withholding taxes paid on behalf of employees on net settled stock-based awards Payment, Tax Withholding, Share-based Payment Arrangement Issuance of restricted stock (shares) Stock Issued During Period, Shares, Restricted Stock Award, Gross Additions Goodwill, Acquired During Period Schedule of Current Available-for-sale Marketable Securities Debt Securities, Available-for-sale [Table Text Block] QUARTERLY RESULTS (UNAUDITED) Quarterly Financial Information [Text Block] Downward adjustments to equity securities without readily determinable fair value Equity Securities without Readily Determinable Fair Value, Downward Price Adjustment, Cumulative Amount Realized gains related to the sale of investments Equity Securities, FV-NI, Unrealized Gain Estimated useful lives (in years) Property, Plant and Equipment, Useful Life Term Loan Loans Payable [Member] Affiliated Entity Affiliated Entity [Member] Goodwill Goodwill [Line Items] Goodwill [Line Items] Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Losses (gains) on long-term investments in equity securities, net Long-term Equity Securities, FV-NI, Realized Gain (Loss) Long-term Equity Securities, FV-NI, Realized Gain (Loss) More Than 5 Years Commercial Commitments, Expiring in Over Five Years Commercial Commitments, Expiring in Over Five Years Share-based Payment Arrangement, Option, Exercise Price Range [Table] Share-based Payment Arrangement, Option, Exercise Price Range [Table] Marketable debt securities Marketable debt securities: Debt Securities, Available-for-sale Income Taxes Paid, Net [Abstract] Income Taxes Paid, Net [Abstract] Accounts receivable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables Share-based Payment Arrangement [Abstract] Share-based Payment Arrangement [Abstract] Schedule of Changes in the Allowance for Credit Losses Accounts Receivable, Allowance for Credit Loss [Table Text Block] Land Land [Member] Current lease liabilities Operating Lease, Liability, Current Vimeo Vimeo [Member] Vimeo [Member] Other Marketplace, Service, Other [Member] Marketplace, Service, Other [Member] Market-Based Stock Options Market-Based Stock Options [Member] Market-Based Stock Options [Member] Forfeited (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Deferred tax assets, adjustment Business Combination, Initial Accounting Incomplete Adjustment, Deferred Tax Assets Business Combination, Initial Accounting Incomplete Adjustment, Deferred Tax Assets Employer contribution per dollar employee contributes up to contribution limit Defined Contribution Plan, Employer Matching Contribution, Percent of Match Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Customer [Domain] Customer [Domain] Cumulative Effect, Period of Adoption, Adjustment Cumulative Effect, Period of Adoption, Adjustment [Member] Additional paid-in capital Additional Paid in Capital, Common Stock Entity Registrant Name Entity Registrant Name Subsequent Event Type [Domain] Subsequent Event Type [Domain] Business Acquisition [Line Items] Business Acquisition [Line Items] Discount rate (as a percent) Operating Lease, Weighted Average Discount Rate, Percent Inter-segment eliminations Intersegment Eliminations [Member] Less: unamortized debt issuance costs Debt Issuance Costs, Net Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Realized gains related to the sale of the investment in Pinterest Gain on Sale of Investments Upward adjustments to the carrying value of equity securities without readily determinable fair values Equity Securities without Readily Determinable Fair Value, Upward Price Adjustment, Cumulative Amount Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Schedule of Supplemental Balance Sheet Information of Leases Assets and Liabilities, Lessee [Table Text Block] Assets and Liabilities, Lessee [Table Text Block] Deferred Tax Assets, Operating Loss Carryforwards, Components [Abstract] Deferred Tax Assets, Operating Loss Carryforwards, Components [Abstract] Schedule of Cash and Cash Equivalents Schedule of Cash and Cash Equivalents [Table Text Block] Accounting Standards Update [Axis] Accounting Standards Update [Axis] Restricted cash included in other assets Restricted Cash, Noncurrent Gross Unrealized Losses Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Tax Credit Carryforward [Table] Tax Credit Carryforward [Table] Sale of Stock [Axis] Sale of Stock [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Market capitalization Market Capitalization Market Capitalization Sold Office Space Sold Office Space [Member] Sold Office Space [Member] Net deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Period Two Debt Instrument, Redemption, Period Two [Member] Incremental compensation cost from modification recognized in year of modification Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost Recognized In Current Period Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost Recognized In Current Period Goodwill Goodwill Balance at beginning of period Balance at end of period Goodwill Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Purchases of investments Payments to Acquire Long-term Investments Warrant Warrant [Member] Net adjustment related to the reconciliation of income tax provision accruals to tax returns Effective Income Tax Reconciliation, Adjustments on the Reconciliation of Income Tax Provisions to Tax Returns, Amount Effective Income Tax Reconciliation, Adjustments on the Reconciliation of Income Tax Provisions to Tax Returns, Amount Net operating loss carryforwards Deferred Tax Assets, Operating Loss Carryforwards Income taxes payable and receivable Increase (Decrease) in Income Taxes Payable Face amount of debt instrument Debt Instrument, Face Amount Realized gains, net, for equity securities sold Equity Securities, FV-NI, Realized Gain (Loss) Other current assets Other current assets Other Assets, Current Schedule of Goodwill by Reporting Unit Schedule of Goodwill [Table Text Block] Forfeited (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Asset Class [Domain] Asset Class [Domain] Allocated costs from related party Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party Equity [Abstract] Equity [Abstract] Total Assets, Fair Value Disclosure Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Capitalization as a result of the Separation (shares) Capitalization as a Result of the Separation, Shares Capitalization as a Result of the Separation, Shares Schedule of Realized and Unrealized Gains (Losses) on Investments Gain (Loss) on Securities [Table Text Block] Redeemable Noncontrolling Interest Redeemable Noncontrolling Interest [Member] Redeemable Noncontrolling Interest [Member] Noncash financial or equity instrument consideration (in shares) Noncash or Part Noncash Acquisition, Noncash Financial or Equity Instrument Consideration, Shares Received Noncash or Part Noncash Acquisition, Noncash Financial or Equity Instrument Consideration, Shares Received Schedule of Goodwill and Intangible Assets, Net Schedule of Intangible Assets and Goodwill [Table Text Block] Indefinite-lived trade name and trademarks Indefinite-lived Intangible Assets Acquired Deferred revenue Current deferred revenue Contract with Customer, Liability, Current Accounting Standards Update [Extensible List] Accounting Standards Update [Extensible List] Accounts payable, trade Accounts Payable, Trade, Current Media Production and Distribution Media Production and Distribution [Member] Media Production and Distribution Granted (USD per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Customer Concentration Risk Customer Concentration Risk [Member] Denominator for earnings per share - weighted average shares (shares) Weighted Average Number of Shares Outstanding, Diluted Schedule of Expected Amortization of Intangible Assets Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Defined Contribution Plan [Table] Defined Contribution Plan [Table] $30.01 to $40.00 Exercise Price Range Three [Member] This element represents the range of exercise prices of stock options from $30.01 to $40.00. Stated term (in years) Term Of Share-Based Compensation Plan Other current liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other Forfeited (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Debt Disclosure [Abstract] Debt Disclosure [Abstract] Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List] Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List] Recoveries collected Accounts Receivable, Allowance for Credit Loss, Recovery Selling and marketing expense Selling and Marketing Expense Accrued expenses Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Schedule of Information for Stock Options Outstanding and Exercisable Share-based Payment Arrangement, Option, Exercise Price Range [Table Text Block] Revenue and Long-lived Assets by Geography Revenues from External Customers and Long-Lived Assets [Line Items] Leverage ratio Debt Instrument, Covenant Terms, Leverage Ratio Debt Instrument, Covenant Terms, Leverage Ratio Balance at beginning of the period Balance at end of the period Unrecognized Tax Benefits Common stock Common Stock, Value, Issued Long-term investments Total long-term investments Investment in MGM Resorts International Long-term Investments Intangible assets with definite lives Finite-Lived Intangible Assets [Line Items] Document Fiscal Year Focus Document Fiscal Year Focus Deferred income taxes Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Equity Method Investment, Number of Shares Acquired Equity Method Investment, Number of Shares Acquired Equity Method Investment, Number of Shares Acquired 2022 Finite-Lived Intangible Asset, Expected Amortization, Year Two Proceeds from the issuance of ANGI Group Senior Notes Proceeds from Issuance of Secured Debt Restricted cash included in other current assets Restricted Cash, Current SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract] SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract] Upward adjustments (gross unrealized gains) Equity Securities without Readily Determinable Fair Value, Upward Price Adjustment, Annual Amount Adjustments to Carrying Value of Equity Securities without Readily Determinable Fair Value [Abstract] Equity Securities, FV-NI, Unrealized Gain (Loss) [Abstract] Current portion of long-term debt Current portion of long-term debt Less: Current portion of long-term debt Long-term Debt, Current Maturities Settlements Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities Entity Current Reporting Status Entity Current Reporting Status Price per share of stock issued in sale of equity capital (in dollars per share) Sale of Stock, Price Per Share Withholding rate (as a percent) Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Withholding Rate Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Withholding Rate Fair value adjustments Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Goodwill Goodwill, Fair Value Disclosure Related Party Transaction [Axis] Related Party Transaction [Axis] Total goodwill and intangible assets, net Intangible Assets, Net (Including Goodwill) Purchases of marketable debt securities Payments to Acquire Debt Securities, Available-for-sale Earnings Per Share Earnings Per Share, Policy [Policy Text Block] Comprehensive income, net of income taxes Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Allowance for credit loss, current and revenue reserve Accounts Receivable, Allowance for Credit Loss, Current and Revenue Reserve Accounts Receivable, Allowance for Credit Loss, Current and Revenue Reserve Common stock issued (shares) Common Stock, Shares, Issued Cash and cash equivalents Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Options outstanding (shares) Share-based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding Total lease liabilities Present value of lease liabilities Operating Lease, Liability Net deferred tax liabilities Deferred Tax Liabilities, Net Long-term debt, net Long-term debt, net Long-term debt, net Long-term Debt, Excluding Current Maturities Segment Reporting [Abstract] Segment Reporting [Abstract] Search Search [Member] Search [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Amortization Adjustment Amortization Adjustment [Member] Amortization Adjustment [Member] Total IAC shareholders' and parent's equity, respectively Stockholders' Equity Attributable to Parent ORGANIZATION Nature of Operations [Text Block] Contractual maturity of current available-for-sale debt securities Contractual Maturity of Current Available-for-Sale Securities Contractual Maturity of Current Available-for-Sale Securities Total purchase price Business Combination, Consideration Transferred Measurement input (as a percent) Alternative Investment, Measurement Input Mosaic Group Mosaic Group [Member] Mosaic Group [Member] Goodwill adjustment Goodwill, Subsequent Recognition of Deferred Tax Asset Entity Address, City or Town Entity Address, City or Town Accrued employee compensation and benefits Employee-related Liabilities, Current Incremental compensation cost Share-based Payment Arrangement, Plan Modification, Incremental Cost Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Less than $20.00 Exercise Price Range One [Member] This element represents the range of exercise prices of stock options from $10.01 to $20.00. Total IAC Shareholders' Equity Parent [Member] 2025 Lessee, Operating Lease, Liability, to be Paid, Year Five Financial Instrument [Axis] Financial Instrument [Axis] Accounting Standards Update [Domain] Accounting Standards Update [Domain] Nonrecurring Adjustment [Axis] Nonrecurring Adjustment [Axis] Short-term lease cost Short-term Lease, Cost Indefinite-lived Intangible Assets [Axis] Indefinite-lived Intangible Assets [Axis] Ask Media Group Ask Media Group [Member] Ask Media Group [Member] Service Agreements Service Agreements [Member] Less: valuation allowance Deferred Tax Assets, Valuation Allowance LIABILITIES: Liabilities: Liabilities [Abstract] Projects in progress Construction in Progress [Member] 2023 Finite-Lived Intangible Asset, Expected Amortization, Year Three ANGI Homeservices Credit Facility ANGI Homeservices Credit Facility [Member] ANGI Homeservices Credit Facility [Member] Income tax benefit related to net operating loss carryforwards Income Tax Expense (Benefit) Related to Operating Loss Carryforwards Represents the amount of income tax expense or benefit related to operating loss carryforwards. Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Total other comprehensive income (loss), net of income taxes Other Comprehensive Income (Loss), Net of Tax Other Comprehensive Income (Loss), Net of Tax Investment, Name [Domain] Investment, Name [Domain] Leases [Abstract] Leases [Abstract] Emerging & Other Emerging & Other Emerging & Other [Member] Emerging & Other [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Total current assets Assets, Current Comprehensive income attributable to noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Earnings Per Share [Abstract] Earnings Per Share [Abstract] Net operating loss carryforwards Operating Loss Carryforwards Quarterly repayments of principal Long-term Debt, Maturities, Quarterly Repayments of Principal Long-term Debt, Maturities, Quarterly Repayments of Principal Schedule of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Anti-dilutive weighted average common shares Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Realized gains (losses) related to the sale of business Gain (Loss) on Disposition of Business Equity Securities, FV-NI, Number of Shares Purchased Equity Securities, FV-NI, Number of Shares Purchased Equity Securities, FV-NI, Number of Shares Purchased Restricted Stock Units (RSUs) & Market Based Stock Units Restricted Stock Units (RSUs) & Market Based Stock Units [Member] Restricted Stock Units (RSUs) & Market Based Stock Units 2025 Finite-Lived Intangible Asset, Expected Amortization, Year Five Stock-based compensation Effective Income Tax Rate Reconciliation, Stock-Based Compensation Effective Income Tax Rate Reconciliation, Stock-Based Compensation Document Fiscal Period Focus Document Fiscal Period Focus SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table] Advertising and Other Advertising and Service, Other [Member] Advertising and Service, Other [Member] Net earnings attributable to IAC shareholders Net Income (Loss) Available to Common Stockholders, Diluted Other (Expense) Income, Net Other (Expense) Income, Net [Member] Other (Expense) Income, Net [Member] Incremental compensation cost from modification recognized in future period Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost that will be Recognized in Future Period Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost that will be Recognized in Future Period Noncontrolling interests created in acquisitions Temporary Equity, Created In Acquisition Temporary Equity, Created In Acquisition Redemption rate (as a percent) Debt Instrument, Redemption Price, Percentage Entity Filer Category Entity Filer Category Common Stock Common Stock [Member] Foreign Currency Translation Adjustment Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Product and Service [Domain] Product and Service [Domain] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Proceeds from the sale of Old IAC Class M common stock Proceeds from the Issuance of Common Stock of Parent Company Proceeds from the Issuance of Common Stock of Parent Company Notes receivable from related parties Notes Receivable, Related Parties Defined contribution plan contributions Defined Contribution Plan, Cost Technology Technology-Based Intangible Assets [Member] Geographic Concentration Risk Geographic Concentration Risk [Member] Care.com Care.com [Member] Care.com [Member] Other Commitments [Axis] Other Commitments [Axis] Downward adjustments including impairments (gross unrealized losses) Equity Securities without Readily Determinable Fair Value, Downward Price Adjustment, Annual Amount Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Vacating office space cost Operating Lease, Cost, Vacating Office Space Operating Lease, Cost, Vacating Office Space Platform Service, Platform [Member] Service, Platform [Member] Amortizable tax basis related to intercompany transaction Effective Income Tax Reconciliation, Amortizable Tax Basis due to Intercompany Transaction, Amount Effective Income Tax Reconciliation, Amortizable Tax Basis due to Intercompany Transaction, Amount Revenue Benchmark Revenue Benchmark [Member] Stated interest rate (as a percent) Debt Instrument, Interest Rate, Stated Percentage Options Exercisable Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable [Abstract] Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable [Abstract] (Gains) losses from the sale of businesses, net Gain (Loss) on Disposition of Business and Investments Gain (Loss) on Disposition of Business and Investments Common Stock Common stock $.001 par value; authorized 1,600,000 shares; 82,976 shares issued and outstanding at December 31, 2020 Class A Common Stock Common Class A [Member] Schedule of Related Party Transactions Schedule of Related Party Transactions [Table Text Block] Cash required to settle vested and unvested interests at fair value Share-based Compensation Arrangement by Share-based Payment Award, Cash Required to Settle Vested and Unvested Interests at fair Value Share-based Compensation Arrangement by Share-based Payment Award, Cash Required to Settle Vested and Unvested Interests at fair Value Earnings (loss) per share attributable to IAC shareholders: Diluted Earnings Per Share, Diluted [Abstract] Other Product and Service, Other [Member] Exercised (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Net increase (decrease) in cash and cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect BUSINESS COMBINATION Business Combination Disclosure [Text Block] Other (expense) income, net Other expense, net Other (expense) income, net Nonoperating Income (Expense) Stock Options Share-based Payment Arrangement, Option [Member] Expedia Expedia [Member] Expedia [Member] Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member] Operating costs and expenses: Costs and Expenses [Abstract] Subsequent Events [Abstract] Subsequent Events [Abstract] Change in foreign currency translation adjustment Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax IAC/InterActiveCorp IAC/InterActiveCorp [Member] IAC/InterActiveCorp [Member] Net increase in Old IAC's investment in IAC Holdings, Inc. Net Increase (Decrease) in Parent Investment in Holdings Company Net Increase (Decrease) in Parent Investment in Holdings Company AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Including Noncontrolling Interest AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Including Noncontrolling Interest [Member] Sale of Stock [Domain] Sale of Stock [Domain] Purchase Commitment - Three Year Cloud Computing Purchase Commitment - Three Year Cloud Computing [Member] Purchase Commitment - Three Year Cloud Computing [Member] Vesting period (in years) Deferred Compensation Arrangement with Individual, Requisite Service Period State Deferred State and Local Income Tax Expense (Benefit) Ownership [Domain] Ownership [Domain] U.S.  Income (Loss) from Continuing Operations before Income Taxes, Domestic Issuance of Vimeo common stock and creation of noncontrolling interest, net of fees Temporary Equity, Creation of Noncontrolling Interest Temporary Equity, Creation of Noncontrolling Interest Interest Interest Paid, Excluding Capitalized Interest, Operating Activities Invested Capital Invested Capital [Member] Invested Capital Equity securities without readily determinable fair values Equity Securities without Readily Determinable Fair Value, Amount Total shareholders' and parent's equity, respectively Balance at beginning of period Balance at end of period Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Federal and State Tax Credits Federal and State Tax Credits [Member] Federal and State Tax Credits Other Affiliates Other Affiliates [Member] Right-of-use assets Deferred Tax Liabilities, Right-of-Use Assets Deferred Tax Liabilities, Right-of-Use Assets Revenue: Revenues 2021 Finite-Lived Intangible Asset, Expected Amortization, Year One Adjustment to the capitalization of tax accounts as a result of the MTCH Separation Adjustment to Additional Paid In Capital, Capitalization of Tax Accounts as a Result of the Separation Adjustment to Additional Paid In Capital, Capitalization of Tax Accounts as a Result of the Separation Class of Stock [Axis] Class of Stock [Axis] Options Outstanding Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding [Abstract] Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding [Abstract] Total Equity Securities without Readily Determinable Fair Value, Annual Amount Equity Securities without Readily Determinable Fair Value, Annual Amount AOCI Attributable to Noncontrolling Interest AOCI Attributable to Noncontrolling Interest [Member] Quarterly Financial Data [Abstract] Quarterly Financial Data [Abstract] Leased Office Space Leased Office Space [Member] Leased Office Space Accrued expenses and other current liabilities Accrued expenses and other current liabilities Accrued Liabilities, Current Diluted earnings per share (USD per share) Loss (earnings) per share (USD per share) Earnings Per Share, Diluted Net proceeds from the sale of businesses and investments Proceeds from Sale of Debt Securities, Available-for-sale Covenant Terms, leverage ratio limiting ability to pay dividends, make distributions, or repurchase stock Debt Instrument, Covenant Terms, Leverage Ratio Limiting Ability to Pay Dividends, Make Distributions, or Repurchase Stock Debt Instrument, Covenant Terms, Leverage Ratio Limiting Ability to Pay Dividends, Make Distributions, or Repurchase Stock Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Consideration transferred, equity interests Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Noncontrolling Interest [Line Items] Noncontrolling Interest [Line Items] Numerator: Diluted Net Income (Loss) Available to Common Stockholders, Diluted [Abstract] Goodwill and Indefinite-Lived Intangible Assets Goodwill and Intangible Assets, Policy [Policy Text Block] Weighted- Average Remaining Contractual Life in Years Share-based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Remaining Contractual Term Schedule of Long-term Debt Schedule of Long-term Debt Instruments [Table Text Block] Depreciation Depreciation Depreciation Entity Address, Address Line One Entity Address, Address Line One Entity Emerging Growth Company Entity Emerging Growth Company Intangible assets with indefinite lives Indefinite-lived Intangible Assets (Excluding Goodwill) Revenue Business Acquisition, Pro Forma Revenue Deferred income taxes Deferred income tax (benefit) provision Deferred Income Tax Expense (Benefit) Angie's List [Member] Angie's List [Member] Angie's List [Member] 3-5 Years Commercial Commitments, Expiring Within Third and Fifth Year Commercial Commitments, Expiring Within Third and Fifth Year Upward adjustments to the carrying value of equity securities without readily determinable fair values Equity Securities without Readily Determinable Fair Value, Net Upward Price Adjustment, Annual Amount Equity Securities without Readily Determinable Fair Value, Upward Price Adjustment, Annual Amount Proportion of ownership interest held each by entity and by related party in aircraft employing flight crew (as a percent) Percentage of Ownership Interest Held Each by Entity and by Related Party in Aircraft Employing Flight Crew Represents the ownership interest in aircraft and entity employing aircraft flight crew that is held by both the reporting entity and a related party. Other current assets: Prepaid Expense and Other Assets, Current [Abstract] Net earnings Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest Contribution of buildings to Match Group Transfer from (to) Related Party Transfer from (to) Related Party Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Maximum Maximum [Member] Number of office buildings transferred to related party Number of Office Buildings Transferred Number of Office Buildings Transferred Noncontrolling Interests Noncontrolling Interest [Member] Stock-based compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Balance at January 1 Balance at December 31 Accounts Receivable, Allowance for Credit Loss Cash withholding obligation equivalent (shares) Share-based Compensation Arrangement by Share-based Payment Award, Cash Withholding Obligation, Shares Share-based Compensation Arrangement by Share-based Payment Award, Cash Withholding Obligation, Shares Trading Symbol Trading Symbol Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Publishing and Applications Publishing And Applications [Member] Publishing And Applications Proceeds from the exercise of ANGI Homeservices stock options Proceeds, Issuance of Shares, Share-based Payment Arrangement, Including Option Exercised Tax credit carryforwards that can be carried forward indefinitely Tax Credit Carryforwards Not Subject to Expiration The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws that can be carried forward indefinitely. Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Foreign Income (Loss) from Continuing Operations before Income Taxes, Foreign Entity Shell Company Entity Shell Company Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Expired (USD per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price Entity Public Float Entity Public Float Business Combinations and Contingent Consideration Arrangements Business Combinations Policy [Policy Text Block] Refunds paid to related party Related Party Transaction, Refunds Paid to Related Party Related Party Transaction, Refunds Paid to Related Party Document Type Document Type ICFR Auditor Attestation Flag ICFR Auditor Attestation Flag Other Other Nonoperating Income (Expense) Segment Reporting, Other Significant Reconciling Item Segment Reporting, Other Significant Reconciling Item [Line Items] Accounts payable and other liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Accrued expenses and other current liabilities: Payables and Accruals [Abstract] Service Service [Member] Schedule of Preliminary Estimated Fair Value of Intangible Assets Acquired Finite-Lived and Indefinite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] Segments [Axis] Segments [Axis] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] Amount by which market capitalization exceeds carrying value Market Capitalization Exceeds Carrying Value, Amount Market Capitalization Exceeds Carrying Value, Amount Vested (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Schedule of Accumulated Other Comprehensive Loss Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Allocation of costs from Old IAC Related Party Transaction, Expenses from Transactions with Related Party Deferred income taxes Deferred Income Tax Liabilities, Net Number of investment banks involved Loss Contingency, Number of Banks Involved Loss Contingency, Number of Banks Involved Intangible assets, net of accumulated amortization Intangible Assets, Net (Excluding Goodwill) Indefinite-lived trade name and trademarks Trademarks and Trade Names [Member] Operating (loss) income Operating loss Operating Income (Loss) Debt issuance costs Payments of Debt Issuance Costs Issuance of ANGI Homeservices common stock pursuant to stock-based awards, net of withholding taxes Issuance of Common Stock Pursuant to Stock-Based Awards, Net of Withholding Taxes Issuance of Common Stock Pursuant to Stock-Based Awards, Net of Withholding Taxes Weighted-average exercise price (USD per share) Share-based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Exercise Price Defined Contribution Plan Disclosure Defined Contribution Plan Disclosure [Line Items] Long-Lived Assets and Intangible Assets with Definite Lives Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block] College Humor Media College Humor Media [Member] College Humor Media [Member] Variable Rate [Axis] Variable Rate [Axis] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Commitments and contingencies Commitments and Contingencies Employee contribution limit per calendar year (up to) (as a percent of pre-tax earnings) Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent Purchase of ANGI Homeservices treasury stock Payments for Repurchase of Common Stock Vesting period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Thereafter Lessee, Operating Lease, Liability, to be Paid, after Year Five Entity Address, State or Province Entity Address, State or Province Vested (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Income tax provision (benefit) at the federal statutory rate of 21% Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Foreign Exchange Translation Goodwill, Foreign Currency Translation Gain (Loss) Sublease income Sublease Income Other Commitments [Table] Other Commitments [Table] Retained earnings Retained Earnings (Accumulated Deficit) Other non-current assets Operating Lease, Right-of-Use Asset $20.01 to $30.00 Exercise Price Range Two [Member] This element represents the range of exercise prices of stock options from $20.01 to $30.00. Income tax payments Income Taxes Paid Property and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment SHAREHOLDERS' AND PARENT'S EQUITY: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Enterprise valuation of Vimeo Enterprise Valuation of Operating Segment Enterprise Valuation of Operating Segment Customer [Axis] Customer [Axis] Redeemable Noncontrolling Interests Redeemable Noncontrolling Interests [Member] This element represents that portion of equity (net assets) in a subsidiary not attributable, directly or indirectly, to the parent. Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Vimeo Credit Facility Vimeo Credit Facility [Member] Vimeo Credit Facility Impact from public subsidiaries' dilutive securities Dilutive Securities, Effect on Basic Earnings Per Share Income Taxes Income Tax, Policy [Policy Text Block] Lease cost Lease, Cost Stock received from related party (shares) Stock Received During Period, Shares, Related Party Stock Received During Period, Shares, Related Party Options exercisable (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Number of service categories Number of Service Categories Number of Service Categories Other, net Payments for (Proceeds from) Other Investing Activities Acquired Intangible Assets [Line Items] Acquired Finite-Lived Intangible Assets [Line Items] Liability Class [Axis] Liability Class [Axis] Tax credit carryforwards related to research and development Tax Credit Carryforward, Related to Research and Development Tax Credit Carryforward, Related to Research and Development Domestic Plan Domestic Plan [Member] Long-term lease liabilities Deferred Tax Assets, Lease Liabilities, Noncurrent Deferred Tax Assets, Lease Liabilities, Noncurrent Period of membership subscription Deferred Revenue, Period of Membership Subscription Deferred Revenue, Period of Membership Subscription Stock-based compensation expense APIC, Share-based Payment Arrangement, Increase for Cost Recognition North America North America [Member] Revenue Revenues Revenue from Contract with Customer, Excluding Assessed Tax Advertising expense Advertising Expense Business Acquisition [Axis] Business Acquisition [Axis] Amortization of capitalized contract costs Capitalized Contract Cost, Amortization Geographical [Domain] Geographical [Domain] Deferred revenue Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue Foreign Deferred Foreign Income Tax Expense (Benefit) Forecast Forecast [Member] Per share information attributable to IAC shareholders: Earnings Per Share, Basic and Diluted [Abstract] Tax credit carryforwards expiring primarily by 2018 and 2037 Tax Credit Carryforward Amount Expiring within Ten Years The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws that will expire within ten years. Unrealized gain on investment in MGM Resorts International Unrealized gain on investment in MGM Resorts International Unrealized gain (loss) on investment Unrealized Gain (Loss) on Investments Revenue Revenue, Segment Benchmark [Member] Entity Voluntary Filers Entity Voluntary Filers Non-current portion of contingent consideration arrangement liability Business Combination, Contingent Consideration, Liability, Noncurrent Business Combination, Acquisition Related Costs Business Combination, Acquisition Related Costs ANGI Homeservices ANGI Homeservices ANGI Homeservices [Member] ANGI Homeservices [Member] Thereafter Finite-Lived Intangible Asset, Expected Amortization, after Year Five Credit Facility [Axis] Credit Facility [Axis] Foreign Tax Authority Foreign Tax Authority [Member] Advertising Advertising [Member] Business Combinations [Abstract] Business Combinations [Abstract] Net earnings (loss) Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual Purchase Commitment - Two Year Cloud Computing Purchase Commitment - Two Year Cloud Computing [Member] Purchase Commitment - Two Year Cloud Computing [Member] Increase (Decrease) in Shareholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Stock-based compensation expense by function: Non Cash Compensation Expense by Function [Abstract] No definition available. Other Advertising, Other [Member] Advertising, Other [Member] Term of options exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Proceeds from issuance of Vimeo common stock, net of fees Proceeds from Issuance of Common Stock Interest coverage ratio Debt Instrument, Covenant Terms, Interest Coverage Ratio Debt Instrument, Covenant Terms, Interest Coverage Ratio Period One Debt Instrument, Redemption, Period One [Member] Capitalization as a result of the MTCH Separation Capitalization as a Result of the Separation, Amount Capitalization as a Result of the Separation, Amount Goodwill Goodwill [Roll Forward] Schedule of Computation of Basic and Diluted Earnings per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] COMMITMENTS AND CONTINGENCIES Commitments Disclosure [Text Block] Warrant Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Goodwill impairment loss, net of tax Goodwill, Impairment Loss, Net of Tax Schedule of Preliminary Estimated Fair Value of Assets Acquired and Liabilities Assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Long-term line of credit Long-term Line of Credit Revenue reserves SEC Schedule, 12-09, Allowance, Sales Returns [Member] SEC Schedule, 12-09, Allowance, Sales Returns [Member] Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Proportion of ownership interest held each by entity and by related party in another entity employing flight crew (as a percent) Percentage of Ownership Interest Held Each by Entity and by Related Party in Another Entity Employing Flight Crew Represents the percentage of the total purchase price of an aircraft paid by both the Company and a related party. Entity Central Index Key Entity Central Index Key Related Party [Domain] Related Party [Domain] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Fair Value Debt Securities, Available-for-sale, Current Due from (to) related party Related Party Transaction, Due from (to) Related Party Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Investment in subsidiaries Deferred Tax Liabilities Investment in Subsidiaries The amount as of the balance sheet date of the estimated future tax effects attributable to investments in subsidiaries. Schedule of Intangible Assets with Definite Lives Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Intangible Assets and Goodwill [Table] Schedule of Intangible Assets and Goodwill [Table] Tabular disclosure of goodwill and intangible assets. Senior Notes Senior Notes [Member] Geographical [Axis] Geographical [Axis] AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Noncontrolling Interest AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Noncontrolling Interest [Member] Change in valuation allowance on capital losses Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Charges to Other Accounts SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Other Account Segments [Domain] Segments [Domain] Amortized Cost Debt Securities, Available-for-sale, Amortized Cost Deferred Revenue Write Off Adjustment Deferred Revenue Write Off Adjustment [Member] Deferred Revenue Write Off Adjustment [Member] Gross Unrealized Gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Tax positions for which the ultimate deductibility is highly certain but timing is uncertain Unrecognized Tax Benefits Unrelated To Federal Income Taxes Statute Of Limitations Expiring To Be Recognized In Subsequent Periods That Would Income Impact Tax Expense Continuing Operations Unrecognized Tax Benefits Unrelated To Federal Income Taxes Statute Of Limitations Expiring To Be Recognized In Subsequent Periods That Would Impact Income Tax Expense Continuing Operations. Net earnings (loss) attributable to IAC shareholders Business Acquisition, Pro Forma Net Income (Loss) Fair value adjustments Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Income Statement Location [Axis] Income Statement Location [Axis] Schedule of Weighted-Average Lease Term and Discount Rate of Leases Schedule of Weighted-Average Lease Term and Discount Rate of Leases [Table Text Block] Schedule of Weighted-Average Lease Term and Discount Rate of Leases [Table Text Block] Weighted- Average Remaining Contractual Life in Years Share-based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Remaining Contractual Term Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Non-deductible goodwill impairment Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Amount Federal Current Federal Tax Expense (Benefit) Change in Accounting Principle, Type [Domain] Change in Accounting Principle, Type [Domain] Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] Amortization of intangibles Amortization of intangibles Amortization of Intangible Assets Legal Costs Legal Costs, Policy [Policy Text Block] Income tax refunds Proceeds from Income Tax Refunds SEGMENT INFORMATION Segment Reporting Disclosure [Text Block] Stock Issued During Period, Value, New Issues Stock Issued During Period, Value, New Issues Scenario [Axis] Scenario [Axis] Title of 12(b) Security Title of 12(b) Security Schedule of Accrued Expenses and Other Current Liabilities Schedule of Accrued Liabilities [Table Text Block] Total gains recognized, net Equity Securities, FV-NI, Gain (Loss) Investment in MGM Resorts International Deferred Tax Liabilities, Investments Intangible assets with definite lives, net of accumulated amortization Total Finite-Lived Intangible Assets, Net Subsidiary of Common Parent Subsidiary of Common Parent [Member] Chief Executive Officer Chief Executive Officer [Member] Interest expense Interest expense Interest Expense Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Proceeds raised from sale of equity capital Sale of Stock, Consideration Received on Transaction Other Stockholders' Equity, Other Schedule of Components of Income Tax Expense (Benefit) Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Impact of Adoption by Segment of ASC 606 Accounting Standards Update and Change in Accounting Principle [Table Text Block] Product and Service [Axis] Product and Service [Axis] Schedule of Debt Instrument Redemption Debt Instrument Redemption [Table Text Block] Number of votes Number of Votes for Each Share of Common Stock Represents the number of votes the holder of each share of common stock is entitled to. Other comprehensive loss, net of income tax Other Comprehensive Income (Loss), Net of Tax, Attributable to Redeemable Noncontrolling Interest Other Comprehensive Income (Loss), Net of Tax, Attributable to Redeemable Noncontrolling Interest Weighted-average period over which cost is expected to be recognized (in years) Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition All other countries Non-US [Member] Accrued advertising expense Accrued Advertising, Current Reconciliation of Other Significant Reconciling Items from Segments to Consolidated [Table] Reconciliation of Other Significant Reconciling Items from Segments to Consolidated [Table] 2022 Long-Term Debt, Maturity, Year Two Deferred revenue recognized during period Contract with Customer, Liability, Revenue Recognized Google Inc. Google Inc [Member] Represents the entity with which company has entered into a paid listing supply agreement for online advertising. Net earnings attributable to IAC shareholders Net (loss) earnings attributable to IAC shareholders Net Income (Loss) Available to Common Stockholders, Basic Directors elected (as a percent) Percentage of Directors Elected by Holders of Common Stock Represents the percentage of the total number of directors the holders of common stock are entitled to elect. Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Proportion of total purchase price and refurbish costs paid in related party transaction (as a percent) Percentage of Total Purchase Price and Refurbish Costs Paid In Related Party Transaction Percentage of Total Purchase Price and Refurbish Costs Paid In Related Party Transaction 2020 Plan 2020 Plan [Member] 2013 Plan [Member] Unrealized reduction in the estimated fair value of a warrant Unrealized Gain (Loss) on Derivatives Equity instruments other than options, aggregate intrinsic value, outstanding Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Outstanding Cash paid (received) during the year for: Cash Paid (Received) [Abstract] Cash Paid (Received) [Abstract] Issuance of Vimeo common stock and creation of noncontrolling interest, net of fees Stock Issued During Period, Value, Creation of Noncontrolling Interest Stock Issued During Period, Value, Creation of Noncontrolling Interest Debt Instrument [Axis] Debt Instrument [Axis] Schedule of Quarterly Results Quarterly Financial Information [Table Text Block] Operating Segments Operating Segments [Member] Class of Stock Class of Stock [Line Items] Payment for contingent consideration liability Payment for Contingent Consideration Liability, Investing Activities Purchase of ANGI Homeservices treasury stock Treasury Stock, Value, Acquired, Cost Method Adjustments to reconcile net earnings to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Litigation Case [Axis] Litigation Case [Axis] Continuing Operations or Discontinued Operations [Domain] Operating Activities [Domain] Variable lease cost Variable Lease, Cost State income taxes, net of effect of federal tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Net operating loss carryforwards subject to expiration within 20 years Operating Loss Carryforwards Subject to Expiration within Twenty Years The amount of the operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws which will expire within twenty years. Tax benefit realized from stock option exercises Deferred Tax Expense from Stock Options Exercised Schedule of Investments [Line Items] Schedule of Investments [Line Items] Options exercisable (shares) Share-based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable Product development expense Research and Development Expense Subsequent Event Subsequent Event [Member] Corporate Aircraft Purchase Corporate Aircraft Purchase [Member] Corporate Aircraft Purchase [Member] Federal Tax Authority Domestic Tax Authority [Member] Reclassifications Reclassification, Comparability Adjustment [Policy Text Block] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Revenue Change Revenue Change [Member] Revenue Change [Member] Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List] Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List] Number of equity method investments Number of Equity Method Investments Number of Equity Method Investments Equity Securities, FV-NI, Unrealized Loss Equity Securities, FV-NI, Unrealized Loss Fair Value Estimate of Fair Value Measurement [Member] Long-term lease liabilities Operating Lease, Liability, Noncurrent 2024 Finite-Lived Intangible Asset, Expected Amortization, Year Four Change in Accounting Principle, Type [Axis] Change in Accounting Principle, Type [Axis] Number of active stock-based compensation plans Share Based Compensation Arrangement by Share Based Payment Award Number of Active Plans Represents the number of active equity-based compensation plans pursuant to which incentive awards are granted to employees, officers, directors and consultants. Less Than 1 Year Commercial commitments due in the next twelve months Commercial Commitments, Expiring within One Year The aggregate amount of commitments expiring in the first year from the balance sheet date to reduce recorded commercial commitments. Tax Credit Carryforwards Tax Credit Carryforward [Line Items] Royalty Rate Measurement Input, Royalty Rate [Member] Measurement Input, Royalty Rate [Member] Subsegments [Domain] Subsegments [Domain] Comprehensive income attributable to IAC shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Documents Incorporated by Reference Documents Incorporated by Reference [Text Block] Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Impairment of note receivable and warrant Impairment of Notes Receivable and Warrants Impairment of Notes Receivable and Warrants Deductions SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction Aggregate Intrinsic Value Share Based Compensation Arrangement by Share Based Payment Award Options Aggregate Intrinsic Value [Abstract] Cash transfers (from) to Old IAC related to its centrally managed U.S. treasury management function, acquisitions and cash expenses paid by Old IAC on behalf of the Company, net Related Party Transactions, Cash Transfers To (From) Related Parties Related Party Transactions, Cash Transfers To (From) Related Parties Legal Entity [Axis] Legal Entity [Axis] City Area Code City Area Code Income Tax Authority [Axis] Income Tax Authority [Axis] Document Period End Date Document Period End Date Operating Lease, Liability, Current, Statement of Financial Position [Extensible List] Operating Lease, Liability, Current, Statement of Financial Position [Extensible List] Net earnings Net earnings Net (loss) earnings Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Gains (losses) reclassified to earnings Amounts reclassified to earnings Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Revenue reserve Revenue Reserve Revenue Reserve Quarterly Financial Information Disclosure [Abstract] Quarterly Financial Information Disclosure [Abstract] Marketable debt securities Debt Securities, Trading, and Equity Securities, FV-NI Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Stock-based compensation expense Share-based Payment Arrangement, Noncash Expense Distributions to and purchases of noncontrolling interests Temporary Equity, Purchase of Interest Temporary Equity, Purchase of Interest Weighted Average Remaining Contractual Term in Years Share Based Compensation Arrangement by Share Based Payment Award Options Weighted Average Remaining Contractual Term [Abstract] Other, net Proceeds from (Payments for) Other Financing Activities Furniture and other equipment Furniture and Other Equipment [Member] Represents the information pertaining to furniture and other equipment. Cover [Abstract] Cover [Abstract] Measurement Input Type [Axis] Measurement Input Type [Axis] Employer contribution limit per calendar year (as a percent of compensation) Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Maturity period at purchase (less than) Cash Equivalents Maturity Period at Purchase Less Than Short-term investments must have a maturity, at the date of purchase, of less than this specified period in order to be classified as cash equivalents. Payments of commercial commitments Payments of Commercial Commitments Payments of Commercial Commitments Other comprehensive (loss) income before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Schedule of Income before Income Taxes Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Note receivable - related party Notes Receivable, Related Parties, Current Total Long-term Debt Deferred revenue Increase (decrease) in deferred revenue Increase (Decrease) in Contract with Customer, Liability LEASES Lessee, Operating Leases [Text Block] Balance of beginning of period Balance at end of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Customer relationships Customer Relationships [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Total operating costs and expenses Costs and Expenses Equity Components [Axis] Equity Components [Axis] Tax Sharing Agreement Tax Sharing Agreement [Member] Tax Sharing Agreement [Member] Hardware Product, Hardware [Member] Product, Hardware [Member] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Deferred tax assets, gross Total deferred tax assets Deferred Tax Assets, Gross Minimum Minimum [Member] Total assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Europe Europe [Member] Schedule of Supplemental Disclosure of Cash Flow Information Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Net loss (earnings) attributable to noncontrolling interests Net loss (earnings) attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Non-current capitalized contract costs Contract with Customer, Asset, after Allowance for Credit Loss, Noncurrent Entity Interactive Data Current Entity Interactive Data Current United States UNITED STATES Schedule of Restricted Cash Restrictions on Cash and Cash Equivalents [Table Text Block] Exercised (USD per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] SHAREHOLDERS' EQUITY Stockholders' Equity Note Disclosure [Text Block] Schedule of Changes in Outstanding Stock Options Share-based Payment Arrangement, Option, Activity [Table Text Block] Components of Deferred Tax Assets and Liabilities Components of Deferred Tax Assets and Liabilities [Abstract] ANGI 3.875% Senior Notes ANGI 3.875% Senior Notes [Member] ANGI 3.875% Senior Notes Schedule of Long-term Investments Long Term Investments [Table Text Block] Tabular disclosure of long term investments. commitment fee (in basis points) Line of Credit Facility, Commitment Fee Percentage Stock-Based Compensation Share-based Payment Arrangement [Policy Text Block] Movement in Valuation Allowances and Reserves SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] Foreign Current Foreign Tax Expense (Benefit) Cash Merger Consideration Paid Cash Merger Consideration Paid Cash Merger Consideration Paid Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Contingent Consideration Arrangements Contingent Consideration Arrangement [Member] Represents potential amounts payable by the entity as contingent consideration in connection with a business acquisition. Total deferred tax liabilities Deferred Tax Liabilities, Gross Accounts Receivable, Allowance for Credit Loss [Roll Forward] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Advertising Costs Advertising Cost [Policy Text Block] Transfers from Old IAC for periods prior to the MTCH Separation Transfers from (to) Parent Company Transfers from (to) Parent Company Consumer Connection Consumer Connection [Member] Consumer Connection [Member] Net operating loss carryforwards not subject to expiration Operating Loss Carryforwards Not Subject to Expiration The amount of the operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws that can be carried forward indefinitely. Schedule of Investments [Table] Schedule of Investments [Table] Acquisition-related Contingent Consideration Fair Value Adjustments Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Axis] Exercise Price Range [Axis] Condensed Income Statements, Captions [Line Items] Condensed Income Statements, Captions [Line Items] Charges to Earnings SEC Schedule, 12-09, Valuation Allowances and Reserves, Additions, Charge to Cost and Expense Consolidation Items [Axis] Consolidation Items [Axis] Product development expense Research and Development Expense [Member] Goodwill impairment Goodwill Impairment Impairment Goodwill, Impairment Loss Accounts receivable, net of allowance and reserves Accounts Receivable, after Allowance for Credit Loss, Current Total Lessee, Operating Lease, Liability, to be Paid Ownership interest (as a percent) Noncontrolling Interest, Ownership Percentage by Parent Other Deferred Tax Assets, Other Foreign Plan Foreign Plan [Member] Deferred tax liabilities: Components of Deferred Tax Liabilities [Abstract] Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period [Domain] Change in judgement on beginning of the year valuation allowance Effective Income Tax Reconciliation, Adjustment to Beginning of Year Valuation Allowance, Amount Effective Income Tax Reconciliation, Adjustment to Beginning of Year Valuation Allowance, Amount Write-off due to deferred revenue Business Combination, Write-Off Due to Deferred Revenue Business Combination, Write-Off Due to Deferred Revenue Foreign Currency Translation and Transaction Gains and Losses Foreign Currency Transactions and Translations Policy [Policy Text Block] Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Basic earnings (loss) per share attributable to ANGI Homeservices Inc. shareholders (USD per share) Business Acquisition, Pro Forma Earnings Per Share, Basic Document Transition Report Document Transition Report Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Intangible assets Deferred Tax Liabilities, Goodwill and Intangible Assets, Intangible Assets and Other The cumulative amount of the estimated future tax effects attributable to the difference between the tax basis of intangible assets and other assets and the basis of intangible assets and other assets computed in accordance with generally accepted accounting principles. Title of Individual [Axis] Title of Individual [Axis] Deferred income tax (benefit) provision: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Other non-current liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Other income (expense), net: Nonoperating Income (Expense) [Abstract] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Cash withholding obligation Share-based Compensation Arrangement by Share-based Payment Award, Cash Withholding Obligation, Amount Share-based Compensation Arrangement by Share-based Payment Award, Cash Withholding Obligation, Amount Current income tax (benefit) provision: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Components of comprehensive income attributable to noncontrolling interests: Other Comprehensive Income (Loss), before Tax, Portion Attributable to Noncontrolling Interest [Abstract] General and administrative expense General and Administrative Expense [Member] Unrecognized tax benefits including tax interest accrued from Old IAC Unrecognized Tax Benefits Including Tax Interest Accrued, Prior Entity The gross amount of unrecognized tax benefits, including interest, pertaining to uncertain tax positions taken in tax returns as of the balance sheet date. Cash merger consideration paid by Old IAC in connection with the MTCH Separation Cash Merger Consideration Received for Separation Cash Merger Consideration Received for Separation Subsequent Event [Line Items] Subsequent Event [Line Items] FINANCIAL STATEMENT DETAILS Additional Financial Information Disclosure [Text Block] Cumulative Effect, Period of Adoption [Axis] Cumulative Effect, Period of Adoption [Axis] Credit Facility [Domain] Credit Facility [Domain] Deferred tax assets: Components of Deferred Tax Assets [Abstract] Litigation Case [Domain] Litigation Case [Domain] Basic earnings per share (USD per share) Loss (earnings) per share (USD per share) Earnings Per Share, Basic 1-3 Years Commercial commitments due between Year One and Year Three Commercial Commitments, Expiring within Second and Third Year The aggregate amount of payments expiring in the second and third year from the balance sheet date to reduce recorded commercial commitments. Impairments related to COVID-19 Asset Impairment Charges, Coronavirus Aid, Relief, and Economic Security Act Asset Impairment Charges, Coronavirus Aid, Relief, and Economic Security Act Entity File Number Entity File Number Expired (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period Term of employment agreement and restricted stock agreement (in years) Term of Employment Agreement and Restricted Stock Agreement Term of Employment Agreement and Restricted Stock Agreement Remaining lease term (in years) Operating Lease, Weighted Average Remaining Lease Term (Deductions) Goodwill Deductions During Period Goodwill Deductions During Period Finite-lived intangible assets acquired Finite-lived Intangible Assets Acquired Purchase obligations Purchase Commitment [Member] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range Share-based Payment Arrangement, Option, Exercise Price Range [Line Items] Total stock-based compensation expense Stock-Based Compensation Expense Stock-based compensation expense Share-based Payment Arrangement, Expense Number of plaintiffs Loss Contingency, Number of Plaintiffs Unrealized Gains On Available-For-Sale Marketable Debt Securities AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member] Membership Subscription Membership Subscription [Member] Membership Subscription [Member] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Document Annual Report Document Annual Report Treasury discount notes Commercial Paper [Member] Options exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Tax benefit recognized related to stock-based compensation Share-based Payment Arrangement, Expense, Tax Benefit Retirement Benefits [Abstract] Retirement Benefits [Abstract] Subsequent Event [Table] Subsequent Event [Table] Issuance of common stock pursuant to stock-based awards, net of withholding taxes (shares) Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Schedule of Income Tax Contingencies Summary of Income Tax Contingencies [Table Text Block] Number of shares required to settle vested and unvested interests at fair value (shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Required to Settle Vested and Unvested Interests at fair Value Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Required to Settle Vested and Unvested Interests at fair Value Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net, Total Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Noncontrolling interests Stockholders' Equity Attributable to Noncontrolling Interest Weighted average grant date fair value of RSUs and PSUs granted (USD per share) Granted (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Business Acquisition, Pro Forma Information [Abstract] Business Acquisition, Pro Forma Information [Abstract] Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Dotdash Dotdash [Member] Dotdash [Member] Non-deductible executive compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Executive Compensation, Amount Effective Income Tax Rate Reconciliation, Nondeductible Expense, Executive Compensation, Amount Other Deferred Tax Liabilities, Other Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Additional consolidated financial statement details Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Litigation Status [Axis] Litigation Status [Axis] Accounts receivable Increase (Decrease) in Accounts Receivable Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Net (increase) decrease in Old IAC's investment in the Company prior to the MTCH Separation Net Increase (Decrease) in Investment from Related Party Net Increase (Decrease) in Investment from Related Party Shares authorized for issuance (in shares) Deferred Compensation Arrangement with Individual, Shares Authorized for Issuance TOTAL LIABILITIES AND SHAREHOLDERS' AND PARENT'S EQUITY, RESPECTIVELY Liabilities and Equity Loss Contingencies [Line Items] Loss Contingencies [Line Items] Accounting Standards Update 2014-09 Accounting Standards Update 2014-09 [Member] Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated Other Comprehensive Income (Loss), Net of Tax Other reserves SEC Schedule, 12-09, Other Reserves [Member] SEC Schedule, 12-09, Other Reserves [Member] INCOME TAXES Income Tax Disclosure [Text Block] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Purchase Commitments - Advertising Purchase Commitments - Advertising [Member] Purchase Commitments - Advertising [Member] Operating lease cost Operating Lease, Cost Time deposits Bank Time Deposits [Member] Additions for tax positions of prior years Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Other Media Content [Member] Pinterest Pinterest [Member] Pinterest [Member] General and administrative expense General and Administrative Expense Impairment of intangible assets Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill), Net of Tax Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill), Net of Tax Potentially dilutive securities excluded from calculation of diluted earnings per share (shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Current income tax (benefit) provision Current Income Tax Expense (Benefit) Other adjustments, net Other Noncash Income (Expense) Restricted Stock Awards Restricted Stock Awards [Member] Restricted Stock Awards Additions for tax positions of prior years Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Additions based on tax positions related to the current year Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Buildings and leasehold improvements Building and Leasehold Improvements [Member] Long lived, depreciable structure held for productive use including structure held by a lessee under a capital lease and any addition or improvement to assets held under lease arrangement (including addition or improvement to asset held by lessee under operating lease arrangement). Weighted-Average Useful Life (Years) Finite-Lived Intangible Asset, Useful Life Equity Component [Domain] Equity Component [Domain] Mark-to-market loss on an indemnification claim related to the Handy acquisition Mark-To-Market Charge Pertaining To Subsidiary Denominated Equity Instrument Mark-To-Market Charge Pertaining To Subsidiary Denominated Equity Instrument Change in unrealized gains and losses on available-for-sale marketable debt securities OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax Building, capitalized software, leasehold improvements and equipment, net Long-lived assets (excluding goodwill and intangible assets) Building, capitalized software, leasehold improvements and equipment, net Property, Plant and Equipment, Net ANGI Group Term Loan due November 5, 2023 ("ANGI Group Term Loan") ANGI Term Loan due November 05, 2023 [Member] ANGI Term Loan due November 05, 2023 [Member] Entity Tax Identification Number Entity Tax Identification Number Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Adjusted EBITDA Adjusted EBITDA Adjusted EBITDA The Company's primary financial measure is Adjusted EBITDA, which is defined as operating income excluding: (1) stock-based compensation expense; (2) depreciation; and (3) acquisition-related items consisting of (i) amortization of intangible assets and impairments of goodwill and intangible assets, if applicable, and (ii) gains and losses recognized on changes in the fair value of contingent consideration arrangements. The Company believes this measure is useful for analysts and investors as this measure allows a more meaningful comparison between our performance and that of our competitors. Moreover, our management uses this measure internally to evaluate the performance of our business as a whole and our individual business segments, and this measure is one of the primary metrics by which our internal budgets are based and by which management is compensated. The above items are excluded from our Adjusted EBITDA measure because these items are non-cash in nature, and we believe that by excluding these items, Adjusted EBITDA corresponds more closely to the cash operating income generated from our business, from which capital investments are made and debt is serviced. Adjusted EBITDA has certain limitations in that it does not take into account the impact to IAC's statement of operations of certain expenses. $40.01 to $50.00 Exercise Price Range Four [Member] This element represents the range of exercise prices of stock options from $40.01 to $50.00. STOCK-BASED COMPENSATION Share-based Payment Arrangement [Text Block] Changes in assets and liabilities, net of effects of acquisitions and dispositions: Increase (Decrease) in Operating Capital [Abstract] Distributions to and purchases of noncontrolling interests Payments to Noncontrolling Interests LIBOR London Interbank Offered Rate (LIBOR) [Member] Trade names Trade Names [Member] Current Fiscal Year End Date Current Fiscal Year End Date Retirement Plan Sponsor Location [Domain] Retirement Plan Sponsor Location [Domain] Schedule of Outstanding Unvested RSUs and MSUs Schedule of Share Based Compensation Restricted Stock Units and Performance Market-Based Units Award Activity [Table Text Block] Tabular disclosure of the number and weighted-average grant date fair value for restricted stock units and performance-based stock units that were outstanding at the beginning and end of the year, and the number of restricted and performance-based stock units that were granted, vested, or forfeited during the year. Intangible Assets and Goodwill Intangible Assets and Goodwill [Line Items] Intangible assets Total identifiable intangible assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Accumulated Other Comprehensive Loss Accumulated Other Comprehensive Income (Loss) [Line Items] Developed technology Developed Technology Rights [Member] Desktop Desktop [Member] Desktop [Member] Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Tax credit carryforwards Deferred Tax Assets, Tax Credit Carryforwards Issuance of restricted stock Stock Issued During Period, Value, Restricted Stock Award, Gross Non-current deferred revenue Contract with Customer, Liability, Noncurrent Stock options granted in period (shares) Granted (shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Term of commercial commitment (in years) Commercial Commitment, Term of Commitment Commercial Commitment, Term of Commitment Match Group Match Group [Member] Match Group - is the world's leading provider of dating products operating a portfolio of over 45 brands, including Match, Tinder, PlentyOfFish and OkCupid. Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Number of service professionals Number of Service Professionals Number of Service Professionals Net earnings Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Property, Plant and Equipment, Type [Domain] Long-Lived Tangible Asset [Domain] Turo Turo [Member] Turo [Member] Marketplace Marketplace [Member] Marketplace [Member] Allowance for credit losses SEC Schedule, 12-09, Allowance, Credit Loss [Member] Fair value at date of acquisition Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss) Due to related parties Due to Related Parties Stock issued during period to related party (shares) Stock Issued During Period, Shares, Related Party Stock Issued During Period, Shares, Related Party Schedule of Estimated Useful Lives of Property and Equipment Schedule of Property and Equipment, Net Property, Plant and Equipment [Table Text Block] Other Commitments [Domain] Other Commitments [Domain] Treasury discount notes US Treasury Securities [Member] Gross Carrying Amount Finite-Lived Intangible Assets, Gross Money market funds Money Market Funds [Member] Provision for credit losses Accounts Receivable, Credit Loss Expense (Reversal) Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Current capitalized contract costs Capitalized costs to obtain a contract with a customer Contract with Customer, Asset, after Allowance for Credit Loss, Current Stock-based compensation expense Temporary Equity, Stock-based Compensation Expense Temporary Equity, Stock-based Compensation Expense Number of plaintiffs who filed a notice of discontinuance of their claims without prejudice Loss Contingency, Number Of Plaintiffs Who Filed A Notice Of Discontinuance Of Their Claims Without Prejudice Loss Contingency, Number Of Plaintiffs Who Filed A Notice Of Discontinuance Of Their Claims Without Prejudice Related Party Transactions [Abstract] Related Party Transactions [Abstract] Fair value at date of acquisition Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Schedule of Maturities of Operating Lease Liabilities Lessee, Operating Lease, Liability, Maturity [Table Text Block] Number of aircraft operated Number of Aircraft Operated Basis of Presentation and Combination Basis of Accounting, Policy [Policy Text Block] Other, net Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Google Advertising Advertising, Google [Member] Advertising, Google [Member] Weighted average basic shares outstanding (shares) Weighted Average Number of Shares Outstanding, Basic Basis spread on variable rate (as a percent) Debt Instrument, Basis Spread on Variable Rate Affiliate Commerce Commission Service, Affiliate Commerce Commission [Member] Service, Affiliate Commerce Commission [Member] Forfeited (USD per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price Ownership [Axis] Ownership [Axis] Document Information [Line Items] Document Information [Line Items] Decrease (increase) in notes receivable - related party Proceeds from Collection of (Payments to Fund) Long-term Loans to Related Parties Increase (Decrease) in Temporary Equity [Roll Forward] Increase (Decrease) in Temporary Equity [Roll Forward] Number of projects Number of Projects Number of Projects Loss Contingencies [Table] Loss Contingencies [Table] Carrying Value Reported Value Measurement [Member] Plan Name [Domain] Plan Name [Domain] Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Change in unrecognized tax benefits unrelated to Federal income taxes statute of limitations expiring within twelve months of current reporting period Change In Unrecognized Tax Benefits Unrelated To The Federal Income Taxes Statute Of Limitations Expiring Reasonably Possible Within Twelve Months Of The Current Reporting Period Change In Unrecognized Tax Benefits Unrelated To The Federal Income Taxes Statute Of Limitations Expiring Reasonably Possible Within Twelve Months Of The Current Reporting Period. Right-of-use assets obtained in exchange for lease liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Income tax benefit (provision) Income tax (benefit) provision Taxes Income Tax Expense (Benefit) Cash and cash equivalents and restricted cash at beginning of period Total cash and cash equivalents and restricted cash as shown on the statement of cash flows Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Purchase of noncontrolling interests Noncontrolling Interest, Change in Redemption Value Building, Capitalized Software, Leasehold Improvements and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Schedule of Aggregate Contractual Maturities of Long-term Debt Schedule of Maturities of Long-term Debt [Table Text Block] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-sale [Table] Title of Individual [Domain] Title of Individual [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Indefinite-lived Intangible Assets, Major Class Name [Domain] Net operating loss carryforwards without restrictions Operating Loss Carryforwards without Restrictions Operating Loss Carryforwards without Restrictions Local Phone Number Local Phone Number Cash acquisition price Payments to Acquire Businesses, Gross Schedule of Pro Forma Financial Information Business Acquisition, Pro Forma Information [Table Text Block] Cumulative Effect, Period of Adoption [Domain] Cumulative Effect, Period of Adoption [Domain] Intrinsic value of stock options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Revenue Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual Schedule of Unobservable Inputs in Fair Value Measurement Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Exercise price range, upper limit (USD per share) Share-based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit Contingent Consideration Arrangements Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Long-term debt Long-term debt, gross Long-term Debt, Gross Put and call arrangements exercised Put and Call Arrangements Exercised Put and Call Arrangements Exercised Related Party Transaction [Domain] Related Party Transaction [Domain] Other assets Increase (Decrease) in Other Operating Assets SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Contingent consideration arrangements, range of outcomes, value, high Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High Schedule of Finite-Lived Intangible Assets by Major Class [Table] Schedule of Finite-Lived Intangible Assets [Table] Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Award Type [Axis] Award Type [Axis] Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Prepaid asset Prepaid Expense and Other Assets Valuation allowance at end of period Deferred Tax Assets Valuation Allowance Amount Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized amount. Principal payments on ANGI Group Term Loan Repayments of Secured Debt Fair value of RSUs and PSUs that vested during the period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Other non-current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Valuation Allowance Valuation Allowance [Abstract] Retained Earnings Retained Earnings [Member] Measurement Basis [Axis] Measurement Basis [Axis] SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Significant Accounting Policies [Text Block] Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Pending Litigation Pending Litigation [Member] Remaining term at end of period Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Award Type [Domain] Award Type [Domain] Adjustment to decrease in amortization of intangible assets Business Acquisition, Pro Forma Information, Adjustment To Increase (Decrease) Amortization Of Intangible Assets Business Acquisition, Pro Forma Information, Adjustment To Increase (Decrease) Amortization Of Intangible Assets Consumer Connection Marketplace, Consumer Connection [Member] Marketplace, Consumer Connection [Member] Options exercisable (USD per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Litigation Status [Domain] Litigation Status [Domain] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Continuing Operations Continuing Operations [Member] EARNINGS PER SHARE Earnings Per Share [Text Block] Change in unrealized gains and losses of available-for-sale marketable debt securities attributable to noncontrolling interests Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest Vimeo Video [Member] Video - consists of Vimeo, Electus, CollegeHumor, Notional, IAC Films and Daily Burn. Redeemable noncontrolling interests Balance at beginning of period Balance at end of period Redeemable Noncontrolling Interest, Equity, Carrying Amount Total Amounts Committed Purchase obligations Commercial Commitments, Expiring The aggregate amount of commercial commitments expiring. Handy Technologies, Inc. Handy Technologies, Inc. [Member] Handy Technologies, Inc. [Member] Accrued revenue share Accrued Revenue Share, Current Accrued Revenue Share, Current Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Discount Rate Measurement Input, Discount Rate [Member] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Earnings (loss) per share attributable to IAC shareholders: Basic Earnings Per Share, Basic [Abstract] Subsegments [Axis] Subsegments [Axis]