v2.4.1.9

BENEFIT PLANS (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Employee contribution limit per calendar year (as a percent of pre-tax earnings)	50.00%us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent	50.00%us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent	50.00%us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Employer contribution limit per calendar year (as a percent of compensation)	3.00%us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent	3.00%us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent	3.00%us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
UNITED STATES
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Defined Benefit Plan, Contributions by Employer	7.5us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution / us-gaap_StatementGeographicalAxis = country_US	6.5us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution / us-gaap_StatementGeographicalAxis = country_US	6.5us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution / us-gaap_StatementGeographicalAxis = country_US
All Other Countries [Member]
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Defined Benefit Plan, Contributions by Employer	2.5us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution / us-gaap_StatementGeographicalAxis = iaci_AllOtherCountriesMember	2.9us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution / us-gaap_StatementGeographicalAxis = iaci_AllOtherCountriesMember	2.3us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution / us-gaap_StatementGeographicalAxis = iaci_AllOtherCountriesMember

X

- Definition

The amount of payment into the fund established for purposes of making future disbursements to the individual in accordance with the terms and understanding of the deferred compensation arrangement.

+ References

No definition available.

+ Details

Name:	us-gaap_DeferredCompensationArrangementWithIndividualEmployerContribution
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Details

Name:	us-gaap_DefinedContributionPensionAndOtherPostretirementPlansDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_StatementGeographicalAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_StatementGeographicalAxis=iaci_AllOtherCountriesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: