Represents the equity interest percentage of each party in a joint venture.

No definition available.

Name:	iaci_EquityInterestPercentageEachParty
Namespace Prefix:	iaci_
Data Type:	num:percentItemType
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Period Type:	instant

Represents the amount of cash paid by the entity for the newly formed venture.

No definition available.

Name:	iaci_NoncashOrPartNoncashAcquisitionCashConsiderationReceived
Namespace Prefix:	iaci_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the value as of balance sheet date of the equity interest in the newly formed venture.

No definition available.

Name:	iaci_NoncashOrPartNoncashAcquisitionInterestAcquiredValue
Namespace Prefix:	iaci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the amount of shares of common stock received in a tax-free exchange in fulfillment of post-closing working capital adjustments.

No definition available.

Name:	iaci_SharesOfCommonStockReceivedInTaxFreeExchange
Namespace Prefix:	iaci_
Data Type:	xbrli:sharesItemType
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Period Type:	duration

Represents the value of the shares of common stock received in a tax-free exchange in fulfillment of post-closing working capital adjustments.

No definition available.

Name:	iaci_ValueOfSharesOfCommonStockReceivedInTaxFreeExchange
Namespace Prefix:	iaci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Name:	us-gaap_NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumedAbstract
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SUPPLEMENTAL CASH FLOW INFORMATION (Details 2) (USD $) Share data in Millions, unless otherwise specified	1 Months Ended		9 Months Ended
	Feb. 28, 2011	Mar. 31, 2010	Sep. 30, 2011	Mar. 10, 2010
Non-Cash Transactions
Shares of IAC common stock received in tax-free exchange with Liberty Media Corporation (in shares)	0.1
Value of the shares of IAC common stock received in tax-free exchange with Liberty Media Corporation	$ 2,923,000		$ 2,923,000
Cash payment from Match to Meetic		3,000,000
Equity interest of Match and Meetic in the newly formed venture (as a percent)				50.00%
Value of equity interest in the newly formed venture				$ 72,000,000