v2.4.1.9

CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net earnings	$ 409,230us-gaap_ProfitLoss	$ 283,725us-gaap_ProfitLoss	$ 160,796us-gaap_ProfitLoss
Other comprehensive (loss) income, net of tax:
Change in foreign currency translation adjustment	(66,874)us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	7,353us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax	712us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax
Change in unrealized gains and losses of available-for-sale securities (net of tax benefits of $1,852, $3,050 and $3,981 in 2014, 2013 and 2012, respectively)	(8,591)us-gaap_AvailableForSaleSecuritiesChangeInNetUnrealizedHoldingGainLossNetOfTax	15,442us-gaap_AvailableForSaleSecuritiesChangeInNetUnrealizedHoldingGainLossNetOfTax	(19,827)us-gaap_AvailableForSaleSecuritiesChangeInNetUnrealizedHoldingGainLossNetOfTax
Total other comprehensive (loss) income	(75,465)us-gaap_OtherComprehensiveIncomeLossNetOfTax	22,795us-gaap_OtherComprehensiveIncomeLossNetOfTax	(19,115)us-gaap_OtherComprehensiveIncomeLossNetOfTax
Comprehensive income	333,765us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	306,520us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	141,681us-gaap_ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest
Comprehensive loss (income) attributable to noncontrolling interests	6,454us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	(1,613)us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest	(2,141)us-gaap_ComprehensiveIncomeNetOfTaxAttributableToNoncontrollingInterest
Comprehensive income attributable to IAC shareholders	$ 340,219us-gaap_ComprehensiveIncomeNetOfTax	$ 304,907us-gaap_ComprehensiveIncomeNetOfTax	$ 139,540us-gaap_ComprehensiveIncomeNetOfTax

X

- Definition

The change in unrealized holding gain (loss), net of tax, on available-for-sale securities included in a separate component of shareholders' equity during the period.

+ References

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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 320



-SubTopic 10



-Section 50



-Paragraph 9



-Subparagraph (d)



-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563

+ Details

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

X

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References

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



-Publisher FASB



-Name Accounting Standards Codification



-Glossary Other Comprehensive Income



-URI http://asc.fasb.org/extlink&oid=6519514







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



-Publisher FASB



-Name Accounting Standards Codification



-Glossary Comprehensive Income



-URI http://asc.fasb.org/extlink&oid=35737396







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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 220



-SubTopic 10



-Section 45



-Paragraph 5



-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e557-108580







Reference 4: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Glossary Net Income



-URI http://asc.fasb.org/extlink&oid=6518256

+ Details

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

X

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References

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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 810



-SubTopic 10



-Section 45



-Paragraph 21



-URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4613674-111683







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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 810



-SubTopic 10



-Section 45



-Paragraph 20



-URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569643-111683







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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 810



-SubTopic 10



-Section 55



-Paragraph 4K



-URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591552-111686

+ Details

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

X

- Definition

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References

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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 810



-SubTopic 10



-Section 55



-Paragraph 4K



-URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591552-111686







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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 810



-SubTopic 10



-Section 45



-Paragraph 19



-URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569616-111683

+ Details

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

X

- Definition

Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

+ References

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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 220



-SubTopic 10



-Section 45



-Paragraph 10A



-Subparagraph (a)



-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580







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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 830



-SubTopic 30



-Section 45



-Paragraph 20



-Subparagraph (b,c)



-URI http://asc.fasb.org/extlink&oid=6915805&loc=d3e32211-110900

+ Details

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

X

- Definition

Amount after tax and reclassification adjustments of other comprehensive income (loss).

+ References

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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 505



-SubTopic 10



-Section 50



-Paragraph 2



-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644







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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 220



-SubTopic 10



-Section 45



-Paragraph 1A



-URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669619-108580

+ Details

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

X

- Details

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

X

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 810



-SubTopic 10



-Section 55



-Paragraph 4K



-URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591552-111686







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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 810



-SubTopic 10



-Section 45



-Paragraph 19



-URI http://asc.fasb.org/extlink&oid=7656940&loc=SL4569616-111683







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



-Publisher FASB



-Name Accounting Standards Codification



-Topic 810



-SubTopic 10



-Section 50



-Paragraph 1A



-Subparagraph (a),(c)



-URI http://asc.fasb.org/extlink&oid=18733093&loc=SL4573702-111684







Reference 4: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 810



-SubTopic 10



-Section 55



-Paragraph 4J



-URI http://asc.fasb.org/extlink&oid=35736750&loc=SL4591551-111686

+ Details

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

X

- Details

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