v2.4.1.9

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue, Major Customer [Line Items]
Revenue	$ 830,754us-gaap_Revenues	$ 782,231us-gaap_Revenues	$ 756,315us-gaap_Revenues	$ 740,247us-gaap_Revenues	$ 724,455us-gaap_Revenues	$ 756,872us-gaap_Revenues	$ 799,411us-gaap_Revenues	$ 742,249us-gaap_Revenues	$ 3,109,547us-gaap_Revenues	$ 3,022,987us-gaap_Revenues	$ 2,800,933us-gaap_Revenues
Accounts receivable	236,086us-gaap_AccountsReceivableNetCurrent				207,408us-gaap_AccountsReceivableNetCurrent				236,086us-gaap_AccountsReceivableNetCurrent	207,408us-gaap_AccountsReceivableNetCurrent
Google Inc.
Revenue, Major Customer [Line Items]
Revenue									1,400,000us-gaap_Revenues / us-gaap_MajorCustomersAxis = iaci_GoogleIncMember	1,500,000us-gaap_Revenues / us-gaap_MajorCustomersAxis = iaci_GoogleIncMember	1,400,000us-gaap_Revenues / us-gaap_MajorCustomersAxis = iaci_GoogleIncMember
Accounts receivable	$ 118,700us-gaap_AccountsReceivableNetCurrent / us-gaap_MajorCustomersAxis = iaci_GoogleIncMember				$ 112,300us-gaap_AccountsReceivableNetCurrent / us-gaap_MajorCustomersAxis = iaci_GoogleIncMember				$ 118,700us-gaap_AccountsReceivableNetCurrent / us-gaap_MajorCustomersAxis = iaci_GoogleIncMember	$ 112,300us-gaap_AccountsReceivableNetCurrent / us-gaap_MajorCustomersAxis = iaci_GoogleIncMember

X

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3-4)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph a(1)

-Article 5



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 4

-Article 5

+ Details

Name:	us-gaap_AccountsReceivableNetCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

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

X

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

+ Details

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	us-gaap_MajorCustomersAxis=iaci_GoogleIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: