GUARANTOR AND NONGUARANTOR FINANCIAL INFORMATION - CONDENSED STATEMENT OF CASH FLOWS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Statement of Cash Flows
Net cash (used in) provided by operating activities attributable to continuing operations	$ 349,405	$ 424,048	$ 410,961
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	(617,402)	(259,391)	(40,434)
Capital expenditures	(62,049)	(57,233)	(80,311)
Proceeds from maturities and sales of marketable debt securities	218,462	21,644	12,502
Purchases of marketable debt securities	(93,134)	(175,826)	0
Proceeds from sales of long-term investments, assets and a business	9,413	58,388	83,091
Purchases of long-term investments	(34,470)	(24,334)	(51,080)
Other, net	(3,541)	(3,042)	(3,529)
Net cash used in investing activities attributable to continuing operations	(582,721)	(439,794)	(79,761)
Cash flows from financing activities attributable to continuing operations:
Borrowings under Match Group Term Loan	788,000	0	0
Debt issuance costs	(19,050)	(383)	(7,399)
Fees and expenses related to note exchange	(6,954)	0	0
Proceeds from issuance of long-term debt	0	0	500,000
Principal payments on long-term debt	(80,000)	0	(15,844)
Proceeds from Match Group initial public offering, net of fees and expenses	428,789	0	0
Purchase of treasury stock	(200,000)	0	(264,214)
Dividends	(113,196)	(97,338)	(79,189)
Issuance of common stock, net of withholding taxes	(38,418)	1,609	(5,077)
Repurchase of stock-based awards	(23,431)	0	0
Excess tax benefits from stock-based awards	56,418	44,957	32,891
Purchase of noncontrolling interests	(32,207)	(33,165)	(67,947)
Funds returned from (transferred to) escrow for Meetic tender offer	0	12,354	(71,512)
Acquisition-related contingent consideration payments	(5,750)	(8,109)	(256)
Intercompany	0	0	0
Other, net	(19,393)	(905)	(3,787)
Net cash provided by (used in) financing activities attributable to continuing operations	734,808	(80,980)	17,666
Total cash provided by (used in) continuing operations	501,492	(96,726)	348,866
Total cash used in discontinued operations	(152)	(145)	(1,877)
Effect of exchange rate changes on cash and cash equivalents	(10,298)	(13,168)	3,478
Net increase (decrease) in cash and cash equivalents	491,042	(110,039)	350,467
Cash and cash equivalents at beginning of period	990,405	1,100,444	749,977
Cash and cash equivalents at end of period	1,481,447	990,405	1,100,444
Inter-segment Elimination
Cash flows from financing activities attributable to continuing operations:
Cash and cash equivalents at beginning of period	0
Cash and cash equivalents at end of period	0	0
IAC
Condensed Statement of Cash Flows
Net cash (used in) provided by operating activities attributable to continuing operations	(139,227)	(109,745)	(84,317)
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	0	0	0
Capital expenditures	(1,332)	(1,843)	(1,387)
Proceeds from maturities and sales of marketable debt securities	218,462	21,644	12,502
Purchases of marketable debt securities	(93,134)	(175,826)
Proceeds from sales of long-term investments, assets and a business	1,277	0	7,839
Purchases of long-term investments	(6,978)	(4,800)	(17,814)
Other, net	3,613	(2,000)	0
Net cash used in investing activities attributable to continuing operations	121,908	(162,825)	1,140
Cash flows from financing activities attributable to continuing operations:
Borrowings under Match Group Term Loan	0
Debt issuance costs	(1,876)	(383)	(7,399)
Fees and expenses related to note exchange	0
Proceeds from issuance of long-term debt			500,000
Principal payments on long-term debt	0		(15,844)
Proceeds from Match Group initial public offering, net of fees and expenses	0
Purchase of treasury stock	(200,000)		(264,214)
Dividends	(113,196)	(97,338)	(79,189)
Issuance of common stock, net of withholding taxes	(38,418)	1,609	(5,077)
Repurchase of stock-based awards	0
Excess tax benefits from stock-based awards	18,034	29,186	21,317
Purchase of noncontrolling interests	0	0	0
Funds returned from (transferred to) escrow for Meetic tender offer		0	0
Acquisition-related contingent consideration payments	0	0	0
Intercompany	683,571	321,192	216,730
Other, net	(19,834)	0	0
Net cash provided by (used in) financing activities attributable to continuing operations	328,281	254,266	366,324
Total cash provided by (used in) continuing operations	310,962	(18,304)	283,147
Total cash used in discontinued operations	(140)	(116)	(1,828)
Effect of exchange rate changes on cash and cash equivalents	0	0	0
Net increase (decrease) in cash and cash equivalents	310,822	(18,420)	281,319
Cash and cash equivalents at beginning of period	762,231	780,651	499,332
Cash and cash equivalents at end of period	1,073,053	762,231	780,651
Guarantor Subsidiaries
Condensed Statement of Cash Flows
Net cash (used in) provided by operating activities attributable to continuing operations	235,424	326,206	336,453
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	(6,078)	(100,683)	(1,356)
Capital expenditures	(23,628)	(27,755)	(54,377)
Proceeds from maturities and sales of marketable debt securities	0	0	0
Purchases of marketable debt securities	0	0
Proceeds from sales of long-term investments, assets and a business	0	0	0
Purchases of long-term investments	0	(2,087)	0
Other, net	(364)	11	220
Net cash used in investing activities attributable to continuing operations	(30,070)	(130,514)	(55,513)
Cash flows from financing activities attributable to continuing operations:
Borrowings under Match Group Term Loan	0
Debt issuance costs	0	0	0
Fees and expenses related to note exchange	0
Proceeds from issuance of long-term debt			0
Principal payments on long-term debt	(80,000)		0
Proceeds from Match Group initial public offering, net of fees and expenses	0
Purchase of treasury stock	0		0
Dividends	0	0	0
Issuance of common stock, net of withholding taxes	0	0	0
Repurchase of stock-based awards	0
Excess tax benefits from stock-based awards	0	0	0
Purchase of noncontrolling interests	0	0	0
Funds returned from (transferred to) escrow for Meetic tender offer		0	0
Acquisition-related contingent consideration payments	(240)	(736)	(256)
Intercompany	(125,114)	(193,672)	(279,779)
Other, net	0	(1,310)	(917)
Net cash provided by (used in) financing activities attributable to continuing operations	(205,354)	(195,718)	(280,952)
Total cash provided by (used in) continuing operations	0	(26)	(12)
Total cash used in discontinued operations	0	0	0
Effect of exchange rate changes on cash and cash equivalents	0	26	12
Net increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	0	0	0
Non-Guarantor Subsidiaries
Condensed Statement of Cash Flows
Net cash (used in) provided by operating activities attributable to continuing operations	253,208	207,587	158,825
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	(611,324)	(158,708)	(39,078)
Capital expenditures	(37,089)	(27,635)	(24,547)
Proceeds from maturities and sales of marketable debt securities	0	0	0
Purchases of marketable debt securities	0	0
Proceeds from sales of long-term investments, assets and a business	8,136	58,388	75,252
Purchases of long-term investments	(27,492)	(17,447)	(33,266)
Other, net	(6,790)	(1,053)	(3,749)
Net cash used in investing activities attributable to continuing operations	(674,559)	(146,455)	(25,388)
Cash flows from financing activities attributable to continuing operations:
Borrowings under Match Group Term Loan	788,000
Debt issuance costs	(17,174)	0	0
Fees and expenses related to note exchange	(6,954)
Proceeds from issuance of long-term debt			0
Principal payments on long-term debt	0		0
Proceeds from Match Group initial public offering, net of fees and expenses	428,789
Purchase of treasury stock	0		0
Dividends	0	0	0
Issuance of common stock, net of withholding taxes	0	0	0
Repurchase of stock-based awards	(23,431)
Excess tax benefits from stock-based awards	38,384	15,771	11,574
Purchase of noncontrolling interests	(32,207)	(33,165)	(67,947)
Funds returned from (transferred to) escrow for Meetic tender offer		12,354	(71,512)
Acquisition-related contingent consideration payments	(5,510)	(7,373)	0
Intercompany	(558,457)	(127,520)	63,049
Other, net	441	405	(2,870)
Net cash provided by (used in) financing activities attributable to continuing operations	611,881	(139,528)	(67,706)
Total cash provided by (used in) continuing operations	190,530	(78,396)	65,731
Total cash used in discontinued operations	(12)	(29)	(49)
Effect of exchange rate changes on cash and cash equivalents	(10,298)	(13,194)	3,466
Net increase (decrease) in cash and cash equivalents	180,220	(91,619)	69,148
Cash and cash equivalents at beginning of period	228,174	319,793	250,645
Cash and cash equivalents at end of period	$ 408,394	$ 228,174	$ 319,793