GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION (Details2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Condensed Financial Statements, Captions [Line Items]
Revenue	$ 771,132	$ 756,315	$ 1,543,644	$ 1,496,562
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	183,276	210,730	374,829	419,964
Selling and marketing expense	319,397	272,490	677,063	571,089
General and administrative expense	129,349	109,897	244,143	204,986
Product development expense	46,430	38,845	91,687	77,661
Depreciation	15,500	15,257	31,068	30,075
Amortization of intangibles	14,411	13,406	26,966	25,385
Total operating costs and expenses	708,363	660,625	1,445,756	1,329,160
Operating income	62,769	95,690	97,888	167,402
Equity in earnings of unconsolidated affiliates			(477)	(8,785)
Interest expense	(15,214)	(14,046)	(29,278)	(28,110)
Other (expense) income, net	(1,638)	(69,750)	5,350	(71,708)
Earnings from continuing operations before income taxes	45,917	11,894	73,960	67,584
Income tax benefit (provision)	11,968	(29,889)	5,788	(51,274)
Earnings (loss) from continuing operations	57,885	(17,995)	79,748	16,310
Loss from discontinued operations, net of tax	(153)	(868)	(28)	(1,682)
Net earnings (loss)	57,732	(18,863)	79,720	14,628
Net loss attributable to noncontrolling interests	1,573	867	5,990	3,261
Net earnings (loss) attributable to IAC shareholders	59,305	(17,996)	85,710	17,889
Comprehensive (loss) income attributable to IAC shareholders	72,283	(20,205)	43,115	21,029
Total Eliminations
Condensed Financial Statements, Captions [Line Items]
Revenue	(3,395)	(3,344)	(6,044)	(6,330)
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	(193)	(687)	(390)	(1,647)
Selling and marketing expense	(3,209)	(2,439)	(5,619)	(4,137)
General and administrative expense	7	13	(35)	26
Product development expense	0	(231)	0	(572)
Depreciation	0	0	0	0
Amortization of intangibles	0	0	0	0
Total operating costs and expenses	(3,395)	(3,344)	(6,044)	(6,330)
Operating income	0	0	0	0
Equity in earnings of unconsolidated affiliates	(83,876)	(13,561)	(141,696)	(68,102)
Interest expense	0	0	0	0
Other (expense) income, net	0	0	0	0
Earnings from continuing operations before income taxes	(83,876)	(13,561)	(141,696)	(68,102)
Income tax benefit (provision)	0	0	0	0
Earnings (loss) from continuing operations	(83,876)	(13,561)	(141,696)	(68,102)
Loss from discontinued operations, net of tax	(3)	27	(3)	40
Net earnings (loss)	(83,879)	(13,534)	(141,699)	(68,062)
Net loss attributable to noncontrolling interests	0	0	0	0
Net earnings (loss) attributable to IAC shareholders	(83,879)	(13,534)	(141,699)	(68,062)
Comprehensive (loss) income attributable to IAC shareholders	(94,235)	(10,284)	(89,526)	(68,865)
IAC Consolidated
Condensed Financial Statements, Captions [Line Items]
Revenue	771,132	756,315	1,543,644	1,496,562
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	183,276	210,730	374,829	419,964
Selling and marketing expense	319,397	272,490	677,063	571,089
General and administrative expense	129,349	109,897	244,143	204,986
Product development expense	46,430	38,845	91,687	77,661
Depreciation	15,500	15,257	31,068	30,075
Amortization of intangibles	14,411	13,406	26,966	25,385
Total operating costs and expenses	708,363	660,625	1,445,756	1,329,160
Operating income	62,769	95,690	97,888	167,402
Equity in earnings of unconsolidated affiliates	0	0	0	0
Interest expense	(15,214)	(14,046)	(29,278)	(28,110)
Other (expense) income, net	(1,638)	(69,750)	5,350	(71,708)
Earnings from continuing operations before income taxes	45,917	11,894	73,960	67,584
Income tax benefit (provision)	11,968	(29,889)	5,788	(51,274)
Earnings (loss) from continuing operations	57,885	(17,995)	79,748	16,310
Loss from discontinued operations, net of tax	(153)	(868)	(28)	(1,682)
Net earnings (loss)	57,732	(18,863)	79,720	14,628
Net loss attributable to noncontrolling interests	1,573	867	5,990	3,261
Net earnings (loss) attributable to IAC shareholders	59,305	(17,996)	85,710	17,889
Comprehensive (loss) income attributable to IAC shareholders	72,283	(20,205)	43,115	21,029
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)	294	383	539	355
Selling and marketing expense	1,010	619	2,065	811
General and administrative expense	33,942	26,609	58,006	49,055
Product development expense	2,330	1,705	4,507	3,176
Depreciation	426	312	827	641
Amortization of intangibles	0	0	0	0
Total operating costs and expenses	38,002	29,628	65,944	54,038
Operating income	(38,002)	(29,628)	(65,944)	(54,038)
Equity in earnings of unconsolidated affiliates	70,523	8,264	124,647	62,561
Interest expense	(12,992)	(12,985)	(25,982)	(25,970)
Other (expense) income, net	(7,506)	6,537	(16,859)	16,222
Earnings from continuing operations before income taxes	12,023	(27,812)	15,862	(1,225)
Income tax benefit (provision)	47,435	10,684	69,876	20,796
Earnings (loss) from continuing operations	59,458	(17,128)	85,738	19,571
Loss from discontinued operations, net of tax	(153)	(868)	(28)	(1,682)
Net earnings (loss)	59,305	(17,996)	85,710	17,889
Net loss attributable to noncontrolling interests	0	0	0	0
Net earnings (loss) attributable to IAC shareholders	59,305	(17,996)	85,710	17,889
Comprehensive (loss) income attributable to IAC shareholders	72,283	(20,205)	43,115	21,029
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenue	586,067	556,162	1,180,868	1,102,488
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	117,383	126,162	237,124	255,463
Selling and marketing expense	264,647	220,152	553,272	456,493
General and administrative expense	66,336	48,459	132,089	94,134
Product development expense	30,996	26,305	62,130	53,401
Depreciation	11,110	9,224	22,690	18,785
Amortization of intangibles	6,226	9,659	12,496	18,660
Total operating costs and expenses	496,698	439,961	1,019,801	896,936
Operating income	89,369	116,201	161,067	205,552
Equity in earnings of unconsolidated affiliates	13,353	5,297	17,049	5,541
Interest expense	(2,211)	(1,052)	(3,257)	(2,094)
Other (expense) income, net	17,787	(13,834)	29,179	(24,361)
Earnings from continuing operations before income taxes	118,298	106,612	204,038	184,638
Income tax benefit (provision)	(40,470)	(39,785)	(72,266)	(69,729)
Earnings (loss) from continuing operations	77,828	66,827	131,772	114,909
Loss from discontinued operations, net of tax	0	0	0	0
Net earnings (loss)	77,828	66,827	131,772	114,909
Net loss attributable to noncontrolling interests	0	0	0	0
Net earnings (loss) attributable to IAC shareholders	77,828	66,827	131,772	114,909
Comprehensive (loss) income attributable to IAC shareholders	79,129	66,163	127,288	114,629
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenue	188,460	203,497	368,820	400,404
Operating costs and expenses:
Cost of revenue (exclusive of depreciation shown separately below)	65,792	84,872	137,556	165,793
Selling and marketing expense	56,949	54,158	127,345	117,922
General and administrative expense	29,064	34,816	54,083	61,771
Product development expense	13,104	11,066	25,050	21,656
Depreciation	3,964	5,721	7,551	10,649
Amortization of intangibles	8,185	3,747	14,470	6,725
Total operating costs and expenses	177,058	194,380	366,055	384,516
Operating income	11,402	9,117	2,765	15,888
Equity in earnings of unconsolidated affiliates	0	0	0	0
Interest expense	(11)	(9)	(39)	(46)
Other (expense) income, net	(11,919)	(62,453)	(6,970)	(63,569)
Earnings from continuing operations before income taxes	(528)	(53,345)	(4,244)	(47,727)
Income tax benefit (provision)	5,003	(788)	8,178	(2,341)
Earnings (loss) from continuing operations	4,475	(54,133)	3,934	(50,068)
Loss from discontinued operations, net of tax	3	(27)	3	(40)
Net earnings (loss)	4,478	(54,160)	3,937	(50,108)
Net loss attributable to noncontrolling interests	1,573	867	5,990	3,261
Net earnings (loss) attributable to IAC shareholders	6,051	(53,293)	9,927	(46,847)
Comprehensive (loss) income attributable to IAC shareholders	$ 15,106	$ (55,879)	$ (37,762)	$ (45,764)