GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION (Details3) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities attributable to continuing operations	$ 42,704	$ 92,362
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	(77,981)	(29,194)
Capital expenditures	(9,721)	(33,638)
Proceeds from maturities and sales of marketable debt securities	0	12,500
Purchases of marketable debt securities	(32,848)	0
Purchases of long-term investments	(7,861)	(975)
Other, net	(157)	(837)
Net cash used in investing activities attributable to continuing operations	(128,568)	(52,144)
Cash flows from financing activities attributable to continuing operations:
Purchase of treasury stock	0	(88,605)
Issuance of common stock, net of withholding taxes	920	552
Dividends	(20,004)	(21,429)
Excess tax benefits from stock-based awards	24,203	12,530
Principal payments on long-term debt	0	(15,844)
Payments to Noncontrolling Interests	(30,000)	0
Funds returned from escrow for Meetic tender offer	12,354	0
Other, net	(295)	(1,101)
Net cash used in financing activities attributable to continuing operations	(12,822)	(113,897)
Total cash used in continuing operations	(98,686)	(73,679)
Total cash (used in) provided by discontinued operations	(63)	2,425
Effect of exchange rate changes on cash and cash equivalents	1,616	(4,966)
Net decrease in cash and cash equivalents	(97,133)	(76,220)
Cash and cash equivalents at beginning of period	1,100,444	749,977
Cash and cash equivalents at end of period	1,003,311	673,757
IAC
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities attributable to continuing operations	(29,250)	(1,106)
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	0	0
Capital expenditures	(985)	(78)
Proceeds from maturities and sales of marketable debt securities		12,500
Purchases of marketable debt securities	(32,848)
Purchases of long-term investments	(3,000)	0
Other, net	2	(55)
Net cash used in investing activities attributable to continuing operations	(36,831)	12,367
Cash flows from financing activities attributable to continuing operations:
Purchase of treasury stock		(88,605)
Issuance of common stock, net of withholding taxes	920	552
Dividends	(20,004)	(21,429)
Excess tax benefits from stock-based awards	15,610	12,530
Principal payments on long-term debt		(15,844)
Payments to Noncontrolling Interests	0
Funds returned from escrow for Meetic tender offer	0
Intercompany Financing Activites	(41,436)	29,317
Other, net	(374)	(927)
Net cash used in financing activities attributable to continuing operations	(45,284)	(84,406)
Total cash used in continuing operations	(111,365)	(73,145)
Total cash (used in) provided by discontinued operations	(50)	2,426
Effect of exchange rate changes on cash and cash equivalents	0	0
Net decrease in cash and cash equivalents	(111,415)	(70,719)
Cash and cash equivalents at beginning of period	782,022	501,075
Cash and cash equivalents at end of period	670,607	430,356
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net cash (used in) provided by operating activities attributable to continuing operations	73,160	106,037
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	(51,263)	(6,060)
Capital expenditures	(5,661)	(28,920)
Proceeds from maturities and sales of marketable debt securities		0
Purchases of marketable debt securities	0
Purchases of long-term investments	(3,286)	0
Other, net	0	0
Net cash used in investing activities attributable to continuing operations	(60,210)	(34,980)
Cash flows from financing activities attributable to continuing operations:
Purchase of treasury stock
Issuance of common stock, net of withholding taxes
Dividends
Excess tax benefits from stock-based awards
Principal payments on long-term debt		0
Payments to Noncontrolling Interests	(30,000)
Funds returned from escrow for Meetic tender offer	0
Intercompany Financing Activites	17,051	(71,056)
Other, net		(29)
Net cash used in financing activities attributable to continuing operations	(12,949)	(71,085)
Total cash used in continuing operations	1	(28)
Total cash (used in) provided by discontinued operations
Effect of exchange rate changes on cash and cash equivalents	(1)	28
Net 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	(1,206)	(12,569)
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	(26,718)	(23,134)
Capital expenditures	(3,075)	(4,640)
Proceeds from maturities and sales of marketable debt securities		0
Purchases of marketable debt securities	0
Purchases of long-term investments	(1,575)	(975)
Other, net	(159)	(782)
Net cash used in investing activities attributable to continuing operations	(31,527)	(29,531)
Cash flows from financing activities attributable to continuing operations:
Purchase of treasury stock
Issuance of common stock, net of withholding taxes
Dividends
Excess tax benefits from stock-based awards	8,593
Principal payments on long-term debt		0
Payments to Noncontrolling Interests	0
Funds returned from escrow for Meetic tender offer	12,354
Intercompany Financing Activites	24,385	41,739
Other, net	79	(145)
Net cash used in financing activities attributable to continuing operations	45,411	41,594
Total cash used in continuing operations	12,678	(506)
Total cash (used in) provided by discontinued operations	(13)	(1)
Effect of exchange rate changes on cash and cash equivalents	1,617	(4,994)
Net decrease in cash and cash equivalents	14,282	(5,501)
Cash and cash equivalents at beginning of period	318,422	248,902
Cash and cash equivalents at end of period	332,704	243,401
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
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:
Purchase of treasury stock		0
Issuance of common stock, net of withholding taxes	0	0
Dividends	0	0
Excess tax benefits from stock-based awards	0	0
Principal payments on long-term debt		0
Payments to Noncontrolling Interests	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
Total cash 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 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	42,704	92,362
Cash flows from investing activities attributable to continuing operations:
Acquisitions, net of cash acquired	(77,981)	(29,194)
Capital expenditures	(9,721)	(33,638)
Proceeds from maturities and sales of marketable debt securities		12,500
Purchases of marketable debt securities	(32,848)
Purchases of long-term investments	(7,861)	(975)
Other, net	(157)	(837)
Net cash used in investing activities attributable to continuing operations	(128,568)	(52,144)
Cash flows from financing activities attributable to continuing operations:
Purchase of treasury stock		(88,605)
Issuance of common stock, net of withholding taxes	920	552
Dividends	(20,004)	(21,429)
Excess tax benefits from stock-based awards	24,203	12,530
Principal payments on long-term debt		(15,844)
Payments to Noncontrolling Interests	(30,000)
Funds returned from escrow for Meetic tender offer	12,354
Intercompany Financing Activites	0	0
Other, net	(295)	(1,101)
Net cash used in financing activities attributable to continuing operations	(12,822)	(113,897)
Total cash used in continuing operations	(98,686)	(73,679)
Total cash (used in) provided by discontinued operations	(63)	2,425
Effect of exchange rate changes on cash and cash equivalents	1,616	(4,966)
Net decrease in cash and cash equivalents	(97,133)	(76,220)
Cash and cash equivalents at beginning of period	1,100,444	749,977
Cash and cash equivalents at end of period	$ 1,003,311	$ 673,757