GOODWILL AND INTANGIBLE ASSETS (Details2) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Balance of goodwill by reporting unit, including the changes in the carrying value of goodwill
Balance at the beginning of the period	$ 1,675,323,000us-gaap_Goodwill	$ 1,616,154,000us-gaap_Goodwill
Additions	165,095,000us-gaap_GoodwillAcquiredDuringPeriod	67,781,000us-gaap_GoodwillAcquiredDuringPeriod
(Deductions)	(35,441,000)iaci_GoodwillDeductionsDuringPeriod	(14,014,000)iaci_GoodwillDeductionsDuringPeriod
Foreign Exchange Translation	(50,051,000)us-gaap_GoodwillTranslationAdjustments	5,402,000us-gaap_GoodwillTranslationAdjustments
Balance at the end of the period	1,754,926,000us-gaap_Goodwill	1,675,323,000us-gaap_Goodwill
Search & Applications
Balance of goodwill by reporting unit, including the changes in the carrying value of goodwill
Balance at the beginning of the period	738,062,000	723,650,000
Additions	71,616,000
(Deductions)	(33,510,000)	(160,000)
Goodwill Transfers During Period		14,572,000
Foreign Exchange Translation	(1,346,000)
Balance at the end of the period	774,822,000	738,062,000
Goodwill accumulated impairment losses	916,900,000	916,900,000	916,900,000
The Match Group
Balance of goodwill by reporting unit, including the changes in the carrying value of goodwill
Balance at the beginning of the period	775,403,000	718,736,000
Additions	72,833,000	62,464,000
(Deductions)	(1,931,000)	(10,675,000)
Foreign Exchange Translation	(47,508,000)	4,878,000
Balance at the end of the period	798,797,000	775,403,000
Media - Connected Ventures
Balance of goodwill by reporting unit, including the changes in the carrying value of goodwill
Balance at the beginning of the period	8,267,000	8,267,000
Additions	0	0
(Deductions)	0	0
Goodwill Transfers During Period		0
Foreign Exchange Translation	0	0
Balance at the end of the period	8,267,000	8,267,000
Goodwill accumulated impairment losses	11,600,000	11,600,000	11,600,000
Total eCommerce
Balance of goodwill by reporting unit, including the changes in the carrying value of goodwill
Balance at the beginning of the period	153,591,000	165,501,000
Additions	20,646,000	5,317,000
(Deductions)		(3,179,000)
Goodwill Transfers During Period		14,572,000
Foreign Exchange Translation	(1,197,000)	524,000
Balance at the end of the period	173,040,000	153,591,000
HomeAdvisor
Balance of goodwill by reporting unit, including the changes in the carrying value of goodwill
Balance at the beginning of the period	131,872,000	111,658,000
Additions	20,646,000	5,317,000
Goodwill Transfers During Period		14,373,000
Foreign Exchange Translation	(1,197,000)	524,000
Balance at the end of the period	151,321,000	131,872,000
CityGrid
Balance of goodwill by reporting unit, including the changes in the carrying value of goodwill
Balance at the beginning of the period		32,124,000
(Deductions)		(3,179,000)
Goodwill Transfers During Period		(28,945,000)
ShoeBuy
Balance of goodwill by reporting unit, including the changes in the carrying value of goodwill
Balance at the beginning of the period	21,719,000	21,719,000
Additions	0	0
(Deductions)	0	0
Goodwill Transfers During Period		0
Foreign Exchange Translation	0	0
Balance at the end of the period	21,719,000	21,719,000
Goodwill accumulated impairment losses	$ 28,000,000	$ 28,000,000	$ 28,000,000

Amount of goodwill deductions during the period, excluding impairments and foreign exchange translation.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase (decrease) from foreign currency translation adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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