GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION (Details3) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities attributable to continuing operations	$ 148,771	$ 228,263
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	(103,637)	(36,913)
Capital expenditures	(26,557)	(47,819)
Proceeds from maturities and sales of marketable debt securities	998	12,502
Proceeds from sales of long-term investments	2,803	310
Purchases of marketable debt securities	(78,380)	0
Purchases of long-term investments	(14,701)	(25,259)
Other, net	(616)	(1,443)
Net cash used in investing activities attributable to continuing operations	(220,090)	(98,622)
Cash flows from financing activities attributable to continuing operations:
Principal payments on long-term debt	0	(15,844)
Purchase of treasury stock	0	(162,660)
Dividends	(40,086)	(38,880)
Issuance of common stock, net of withholding taxes	(13,823)	(868)
Excess tax benefits from stock-based awards	32,889	23,547
Purchase of noncontrolling interest	(30,000)	0
Funds returned from escrow for Meetic tender offer	12,354	0
Acquisition-related contingent consideration payment	(7,373)	0
Other, net	(141)	(3,634)
Net cash used in financing activities attributable to continuing operations	(46,180)	(198,339)
Net Cash Provided by (Used in) Continuing Operations	(117,499)	(68,698)
Total cash (used in) provided by discontinued operations	(157)	2,335
Effect of exchange rate changes on cash and cash equivalents	4,538	(4,889)
Net increase (decrease) in cash and cash equivalents	(113,118)	(71,252)
Cash and cash equivalents at beginning of period	1,100,444	749,977
Cash and cash equivalents at end of period	987,326	678,725
IAC
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities attributable to continuing operations	(38,576)	(32,997)
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	0	0
Capital expenditures	(2,390)	(719)
Proceeds from maturities and sales of marketable debt securities	998	12,502
Proceeds from sales of long-term investments	0	0
Purchases of marketable debt securities	(78,380)
Purchases of long-term investments	(3,000)	(17,362)
Other, net	0	(55)
Net cash used in investing activities attributable to continuing operations	(82,772)	(5,634)
Cash flows from financing activities attributable to continuing operations:
Principal payments on long-term debt		(15,844)
Purchase of treasury stock		(162,660)
Dividends	(40,086)	(38,880)
Issuance of common stock, net of withholding taxes	(13,823)	(868)
Excess tax benefits from stock-based awards	22,116	23,547
Purchase of noncontrolling interest	0
Funds returned from escrow for Meetic tender offer	0
Intercompany Financing Activites	104,410	144,320
Other, net	(383)	(927)
Net cash used in financing activities attributable to continuing operations	72,234	(51,312)
Net Cash Provided by (Used in) Continuing Operations	(49,114)	(89,943)
Total cash (used in) provided by discontinued operations	(116)	2,335
Effect of exchange rate changes on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	(49,230)	(87,608)
Cash and cash equivalents at beginning of period	782,022	501,075
Cash and cash equivalents at end of period	732,792	413,467
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities attributable to continuing operations	193,388	260,013
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	(88,462)	(6,572)
Capital expenditures	(16,477)	(39,071)
Proceeds from maturities and sales of marketable debt securities	0	0
Proceeds from sales of long-term investments	0	0
Purchases of marketable debt securities	0
Purchases of long-term investments	(6,761)	0
Other, net	11	38
Net cash used in investing activities attributable to continuing operations	(111,689)	(45,605)
Cash flows from financing activities attributable to continuing operations:
Principal payments on long-term debt		0
Purchase of treasury stock
Dividends
Issuance of common stock, net of withholding taxes
Excess tax benefits from stock-based awards
Purchase of noncontrolling interest	(30,000)
Funds returned from escrow for Meetic tender offer	0
Intercompany Financing Activites	(51,723)	(213,207)
Other, net		(1,224)
Net cash used in financing activities attributable to continuing operations	(81,723)	(214,431)
Net Cash Provided by (Used in) Continuing Operations	(24)	(23)
Total cash (used in) provided by discontinued operations
Effect of exchange rate changes on cash and cash equivalents	24	23
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0	0
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities attributable to continuing operations	(6,041)	1,247
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	(15,175)	(30,341)
Capital expenditures	(7,690)	(8,029)
Proceeds from maturities and sales of marketable debt securities	0	0
Proceeds from sales of long-term investments	2,803	310
Purchases of marketable debt securities	0
Purchases of long-term investments	(4,940)	(7,897)
Other, net	(627)	(1,426)
Net cash used in investing activities attributable to continuing operations	(25,629)	(47,383)
Cash flows from financing activities attributable to continuing operations:
Principal payments on long-term debt		0
Purchase of treasury stock
Dividends
Issuance of common stock, net of withholding taxes
Excess tax benefits from stock-based awards	10,773
Purchase of noncontrolling interest	0
Funds returned from escrow for Meetic tender offer	12,354
Acquisition-related contingent consideration payment	(7,373)
Intercompany Financing Activites	(52,687)	68,887
Other, net	242	(1,483)
Net cash used in financing activities attributable to continuing operations	(36,691)	67,404
Net Cash Provided by (Used in) Continuing Operations	(68,361)	21,268
Total cash (used in) provided by discontinued operations	(41)
Effect of exchange rate changes on cash and cash equivalents	4,514	(4,912)
Net increase (decrease) in cash and cash equivalents	(63,888)	16,356
Cash and cash equivalents at beginning of period	318,422	248,902
Cash and cash equivalents at end of period	254,534	265,258
Total Eliminations
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities attributable to continuing operations	0	0
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	0	0
Capital expenditures	0	0
Proceeds from maturities and sales of marketable debt securities	0	0
Proceeds from sales of long-term investments	0	0
Purchases of marketable debt securities	0
Purchases of long-term investments	0	0
Other, net	0	0
Net cash used in investing activities attributable to continuing operations	0	0
Cash flows from financing activities attributable to continuing operations:
Principal payments on long-term debt		0
Purchase of treasury stock		0
Dividends	0	0
Issuance of common stock, net of withholding taxes	0	0
Excess tax benefits from stock-based awards	0	0
Purchase of noncontrolling interest	0
Funds returned from escrow for Meetic tender offer	0
Intercompany Financing Activites	0	0
Other, net	0	0
Net cash used in financing activities attributable to continuing operations	0	0
Net Cash Provided by (Used in) Continuing Operations	0	0
Total cash (used in) provided by discontinued operations	0	0
Effect of exchange rate changes on cash and cash equivalents	0	0
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0	0
IAC Consolidated
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities attributable to continuing operations	148,771	228,263
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	(103,637)	(36,913)
Capital expenditures	(26,557)	(47,819)
Proceeds from maturities and sales of marketable debt securities	998	12,502
Proceeds from sales of long-term investments	2,803	310
Purchases of marketable debt securities	(78,380)
Purchases of long-term investments	(14,701)	(25,259)
Other, net	(616)	(1,443)
Net cash used in investing activities attributable to continuing operations	(220,090)	(98,622)
Cash flows from financing activities attributable to continuing operations:
Principal payments on long-term debt		(15,844)
Purchase of treasury stock		(162,660)
Dividends	(40,086)	(38,880)
Issuance of common stock, net of withholding taxes	(13,823)	(868)
Excess tax benefits from stock-based awards	32,889	23,547
Purchase of noncontrolling interest	(30,000)
Funds returned from escrow for Meetic tender offer	12,354
Acquisition-related contingent consideration payment	(7,373)
Intercompany Financing Activites	0	0
Other, net	(141)	(3,634)
Net cash used in financing activities attributable to continuing operations	(46,180)	(198,339)
Net Cash Provided by (Used in) Continuing Operations	(117,499)	(68,698)
Total cash (used in) provided by discontinued operations	(157)	2,335
Effect of exchange rate changes on cash and cash equivalents	4,538	(4,889)
Net increase (decrease) in cash and cash equivalents	(113,118)	(71,252)
Cash and cash equivalents at beginning of period	1,100,444	749,977
Cash and cash equivalents at end of period	$ 987,326	$ 678,725