GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION (Details2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Revenue	$ 740,247	$ 742,249
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	209,194	255,849
Selling and marketing expense	298,712	242,914
General and administrative expense	94,816	95,724
Product development expense	39,016	35,117
Depreciation	14,818	14,016
Amortization of intangibles	11,979	14,078
Total operating costs and expenses	668,535	657,698
Operating income	71,712	84,551
Equity in losses of unconsolidated affiliates	(1,935)	(91)
Interest expense	(14,064)	(7,663)
Other (expense) income, net	(23)	1,658
Earnings from continuing operations before income taxes	55,690	78,455
Income tax provision	(21,385)	(25,746)
Earnings from continuing operations	34,305	52,709
Loss from discontinued operations, net of tax	(814)	(944)
Net earnings	33,491	51,765
Net loss attributable to noncontrolling interests	2,394	1,872
Net earnings attributable to IAC shareholders	35,885	53,637
Comprehensive income attributable to IAC shareholders	41,234	41,710
IAC
Condensed Financial Statements, Captions [Line Items]
Revenue	0	0
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	(28)	677
Selling and marketing expense	192	431
General and administrative expense	22,446	22,245
Product development expense	1,471	899
Depreciation	329	367
Amortization of intangibles	0	0
Total operating costs and expenses	24,410	24,619
Operating income	(24,410)	(24,619)
Equity in losses of unconsolidated affiliates	54,259	114,550
Interest expense	(12,985)	(6,557)
Other (expense) income, net	9,699	(55,448)
Earnings from continuing operations before income taxes	26,563	27,926
Income tax provision	10,136	26,655
Earnings from continuing operations	36,699	54,581
Loss from discontinued operations, net of tax	(814)	(944)
Net earnings	35,885	53,637
Net loss attributable to noncontrolling interests	0	0
Net earnings attributable to IAC shareholders	35,885	53,637
Comprehensive income attributable to IAC shareholders	41,234	41,710
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenue	518,264	528,644
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	116,751	153,800
Selling and marketing expense	226,801	182,743
General and administrative expense	40,991	40,273
Product development expense	25,969	23,042
Depreciation	9,293	9,249
Amortization of intangibles	8,277	8,962
Total operating costs and expenses	428,082	418,069
Operating income	90,182	110,575
Equity in losses of unconsolidated affiliates	8,422	2,396
Interest expense	(1,042)	(1,065)
Other (expense) income, net	(8,751)	(18,138)
Earnings from continuing operations before income taxes	88,811	93,768
Income tax provision	(30,161)	(33,806)
Earnings from continuing operations	58,650	59,962
Loss from discontinued operations, net of tax	0	0
Net earnings	58,650	59,962
Net loss attributable to noncontrolling interests	0	8
Net earnings attributable to IAC shareholders	58,650	59,970
Comprehensive income attributable to IAC shareholders	59,032	59,895
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenue	223,587	214,642
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	93,431	102,151
Selling and marketing expense	72,035	59,997
General and administrative expense	31,366	33,207
Product development expense	11,917	11,176
Depreciation	5,196	4,400
Amortization of intangibles	3,702	5,116
Total operating costs and expenses	217,647	216,047
Operating income	5,940	(1,405)
Equity in losses of unconsolidated affiliates	(27)	(91)
Interest expense	(37)	(41)
Other (expense) income, net	(971)	75,244
Earnings from continuing operations before income taxes	4,905	73,707
Income tax provision	(1,360)	(18,595)
Earnings from continuing operations	3,545	55,112
Loss from discontinued operations, net of tax	(13)	7
Net earnings	3,532	55,119
Net loss attributable to noncontrolling interests	2,394	1,864
Net earnings attributable to IAC shareholders	5,926	56,983
Comprehensive income attributable to IAC shareholders	9,622	40,890
Total Eliminations
Condensed Financial Statements, Captions [Line Items]
Revenue	(1,604)	(1,037)
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	(960)	(779)
Selling and marketing expense	(316)	(257)
General and administrative expense	13	(1)
Product development expense	(341)	0
Depreciation	0	0
Amortization of intangibles	0	0
Total operating costs and expenses	(1,604)	(1,037)
Operating income	0	0
Equity in losses of unconsolidated affiliates	(64,589)	(116,946)
Interest expense	0	0
Other (expense) income, net	0	0
Earnings from continuing operations before income taxes	(64,589)	(116,946)
Income tax provision	0	0
Earnings from continuing operations	(64,589)	(116,946)
Loss from discontinued operations, net of tax	13	(7)
Net earnings	(64,576)	(116,953)
Net loss attributable to noncontrolling interests	0	0
Net earnings attributable to IAC shareholders	(64,576)	(116,953)
Comprehensive income attributable to IAC shareholders	(68,654)	(100,785)
IAC Consolidated
Condensed Financial Statements, Captions [Line Items]
Revenue	740,247	742,249
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	209,194	255,849
Selling and marketing expense	298,712	242,914
General and administrative expense	94,816	95,724
Product development expense	39,016	35,117
Depreciation	14,818	14,016
Amortization of intangibles	11,979	14,078
Total operating costs and expenses	668,535	657,698
Operating income	71,712	84,551
Equity in losses of unconsolidated affiliates	(1,935)	(91)
Interest expense	(14,064)	(7,663)
Other (expense) income, net	(23)	1,658
Earnings from continuing operations before income taxes	55,690	78,455
Income tax provision	(21,385)	(25,746)
Earnings from continuing operations	34,305	52,709
Loss from discontinued operations, net of tax	(814)	(944)
Net earnings	33,491	51,765
Net loss attributable to noncontrolling interests	2,394	1,872
Net earnings attributable to IAC shareholders	35,885	53,637
Comprehensive income attributable to IAC shareholders	$ 41,234	$ 41,710