GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION (Details2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Condensed Financial Statements, Captions [Line Items]
Revenue	$ 782,231	$ 756,872	$ 2,278,793	$ 2,298,532
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	226,192	248,856	646,486	777,527
Selling and marketing expense	276,623	248,282	848,121	738,349
General and administrative expense	108,193	75,977	312,728	275,216
Product development expense	39,686	35,232	117,059	104,401
Depreciation	14,133	13,489	44,208	44,541
Amortization of intangibles	16,451	13,032	41,836	45,247
Total operating costs and expenses	681,278	634,868	2,010,438	1,985,281
Operating income	100,953	122,004	268,355	313,251
Equity in losses of unconsolidated affiliates	(612)	(3,253)	(9,397)	(4,422)
Interest expense	(14,009)	(7,623)	(42,119)	(22,944)
Other income (expense), net	4,113	16,719	(58,810)	18,373
Earnings from continuing operations before income taxes	90,445	127,847	158,029	304,258
Income tax benefit (provision)	59,816	(36,126)	8,542	(101,288)
Earnings from continuing operations	150,261	91,721	166,571	202,970
Loss from discontinued operations, net of tax	175,730	3,914	174,048	1,902
Net earnings	325,991	95,635	340,619	204,872
Net loss attributable to noncontrolling interests	821	1,305	4,082	3,995
Net earnings attributable to IAC shareholders	326,812	96,940	344,701	208,867
Comprehensive income attributable to IAC shareholders	289,950	122,502	310,979	234,411
IAC
Condensed Financial Statements, Captions [Line Items]
Revenue	0	0	0	0
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	387	578	742	1,804
Selling and marketing expense	723	743	1,534	1,884
General and administrative expense	28,046	23,334	77,101	69,161
Product development expense	1,935	1,321	5,111	3,087
Depreciation	402	340	1,043	1,051
Amortization of intangibles	0	0	0	0
Total operating costs and expenses	31,493	26,316	85,531	76,987
Operating income	(31,493)	(26,316)	(85,531)	(76,987)
Equity in losses of unconsolidated affiliates	91,137	95,701	150,531	286,178
Interest expense	(12,948)	(6,520)	(38,918)	(19,592)
Other income (expense), net	(8,311)	20,882	11,077	(31,457)
Earnings from continuing operations before income taxes	38,385	83,747	37,159	158,142
Income tax benefit (provision)	112,697	9,279	133,494	48,823
Earnings from continuing operations	151,082	93,026	170,653	206,965
Loss from discontinued operations, net of tax	175,730	3,914	174,048	1,902
Net earnings	326,812	96,940	344,701	208,867
Net loss attributable to noncontrolling interests	0	0	0	0
Net earnings attributable to IAC shareholders	326,812	96,940	344,701	208,867
Comprehensive income attributable to IAC shareholders	289,950	122,502	310,979	234,411
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenue	557,604	545,940	1,660,092	1,659,383
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	121,230	138,715	374,326	457,756
Selling and marketing expense	218,976	197,064	675,025	584,005
General and administrative expense	50,317	39,824	146,448	129,673
Product development expense	27,294	25,361	81,509	74,148
Depreciation	8,887	8,343	27,671	29,878
Amortization of intangibles	10,259	9,191	28,919	30,640
Total operating costs and expenses	436,963	418,498	1,333,898	1,306,100
Operating income	120,641	127,442	326,194	353,283
Equity in losses of unconsolidated affiliates	13,248	17,684	16,595	27,807
Interest expense	(1,050)	(1,061)	(3,144)	(3,204)
Other income (expense), net	8,771	(9,768)	(9,935)	(37,286)
Earnings from continuing operations before income taxes	141,610	134,297	329,710	340,600
Income tax benefit (provision)	(44,658)	(41,542)	(114,388)	(116,053)
Earnings from continuing operations	96,952	92,755	215,322	224,547
Loss from discontinued operations, net of tax	0	0	0	0
Net earnings	96,952	92,755	215,322	224,547
Net loss attributable to noncontrolling interests	0	0	0	0
Net earnings attributable to IAC shareholders	96,952	92,755	215,322	224,547
Comprehensive income attributable to IAC shareholders	93,955	93,189	212,045	224,843
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenue	227,629	212,022	628,033	642,435
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	105,263	110,192	273,753	320,375
Selling and marketing expense	59,197	50,822	177,972	153,216
General and administrative expense	29,820	12,933	89,143	76,504
Product development expense	10,508	8,550	31,062	27,166
Depreciation	4,844	4,806	15,494	13,612
Amortization of intangibles	6,192	3,841	12,917	14,607
Total operating costs and expenses	215,824	191,144	600,341	605,480
Operating income	11,805	20,878	27,692	36,955
Equity in losses of unconsolidated affiliates	95	(56)	132	(279)
Interest expense	(11)	(42)	(57)	(148)
Other income (expense), net	3,653	5,605	(59,952)	87,116
Earnings from continuing operations before income taxes	15,542	26,385	(32,185)	123,644
Income tax benefit (provision)	(8,223)	(3,863)	(10,564)	(34,058)
Earnings from continuing operations	7,319	22,522	(42,749)	89,586
Loss from discontinued operations, net of tax	5	3	(35)	14
Net earnings	7,324	22,525	(42,784)	89,600
Net loss attributable to noncontrolling interests	821	1,305	4,082	3,995
Net earnings attributable to IAC shareholders	8,145	23,830	(38,702)	93,595
Comprehensive income attributable to IAC shareholders	(28,940)	36,262	(74,704)	84,437
Total Eliminations
Condensed Financial Statements, Captions [Line Items]
Revenue	(3,002)	(1,090)	(9,332)	(3,286)
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	(688)	(629)	(2,335)	(2,408)
Selling and marketing expense	(2,273)	(347)	(6,410)	(756)
General and administrative expense	10	(114)	36	(122)
Product development expense	(51)	0	(623)	0
Depreciation	0	0	0	0
Amortization of intangibles	0	0	0	0
Total operating costs and expenses	(3,002)	(1,090)	(9,332)	(3,286)
Operating income	0	0	0	0
Equity in losses of unconsolidated affiliates	(105,092)	(116,582)	(176,655)	(318,128)
Interest expense	0	0	0	0
Other income (expense), net	0	0	0	0
Earnings from continuing operations before income taxes	(105,092)	(116,582)	(176,655)	(318,128)
Income tax benefit (provision)	0	0	0	0
Earnings from continuing operations	(105,092)	(116,582)	(176,655)	(318,128)
Loss from discontinued operations, net of tax	(5)	(3)	35	(14)
Net earnings	(105,097)	(116,585)	(176,620)	(318,142)
Net loss attributable to noncontrolling interests	0	0	0	0
Net earnings attributable to IAC shareholders	(105,097)	(116,585)	(176,620)	(318,142)
Comprehensive income attributable to IAC shareholders	(65,015)	(129,451)	(137,341)	(309,280)
IAC Consolidated
Condensed Financial Statements, Captions [Line Items]
Revenue	782,231	756,872	2,278,793	2,298,532
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	226,192	248,856	646,486	777,527
Selling and marketing expense	276,623	248,282	848,121	738,349
General and administrative expense	108,193	75,977	312,728	275,216
Product development expense	39,686	35,232	117,059	104,401
Depreciation	14,133	13,489	44,208	44,541
Amortization of intangibles	16,451	13,032	41,836	45,247
Total operating costs and expenses	681,278	634,868	2,010,438	1,985,281
Operating income	100,953	122,004	268,355	313,251
Equity in losses of unconsolidated affiliates	(612)	(3,253)	(9,397)	(4,422)
Interest expense	(14,009)	(7,623)	(42,119)	(22,944)
Other income (expense), net	4,113	16,719	(58,810)	18,373
Earnings from continuing operations before income taxes	90,445	127,847	158,029	304,258
Income tax benefit (provision)	59,816	(36,126)	8,542	(101,288)
Earnings from continuing operations	150,261	91,721	166,571	202,970
Loss from discontinued operations, net of tax	175,730	3,914	174,048	1,902
Net earnings	325,991	95,635	340,619	204,872
Net loss attributable to noncontrolling interests	821	1,305	4,082	3,995
Net earnings attributable to IAC shareholders	326,812	96,940	344,701	208,867
Comprehensive income attributable to IAC shareholders	$ 289,950	$ 122,502	$ 310,979	$ 234,411