GUARANTOR AND NON-GUARANTOR FINANCIAL INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 678,725	$ 749,977	$ 807,196	$ 704,153
Marketable securities	7,775	20,604
Accounts receivable, net	235,950	229,830
Other current assets	148,285	156,339
Property and equipment, net	289,493	270,512
Goodwill	1,664,315	1,616,154
Intangible assets, net	466,161	482,904
Other non-current assets	124,976	118,230
TOTAL ASSETS	3,812,491	3,805,828
LIABILITIES AND SHAREHOLDERS' EQUITY
Accounts payable, trade	83,294	98,314
Long-term debt, net of current maturities	580,000	580,000
Income taxes payable	496,168	479,945
Other long-term liabilities	66,081	31,830
Redeemable noncontrolling interests	64,147	58,126
IAC shareholders' equity	1,631,305	1,655,728
Noncontrolling interests	51,229	51,907
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	3,812,491	3,805,828
IAC
ASSETS
Cash and cash equivalents	413,467	501,075	599,722	545,222
Marketable securities	7,775	20,604
Accounts receivable, net	11	43
Other current assets	26,226	58,452
Intercompany receivables	0	0
Property and equipment, net	4,378	4,116
Goodwill	0	0
Intangible assets, net	0	0
Investment in subsidiaries	4,377,565	12,913,694
Other non-current assets	181,304	153,155
TOTAL ASSETS	5,010,726	13,651,139
LIABILITIES AND SHAREHOLDERS' EQUITY
Accounts payable, trade	1,543	4,366
Other Liabilities, Current	38,823	74,214
Long-term debt, net of current maturities	500,000	500,000
Income taxes payable	440,261	440,110
Intercompany liabilities	2,184,582	10,759,104
Other long-term liabilities	214,212	217,617
Redeemable noncontrolling interests	0	0
IAC shareholders' equity	1,631,305	1,655,728
Noncontrolling interests	0	0
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	5,010,726	13,651,139
Guarantor Subsidiaries
ASSETS
Cash and cash equivalents	0	0	0	0
Marketable securities	0	0
Accounts receivable, net	151,153	142,627
Other current assets	66,061	53,720
Intercompany receivables	415,915	482,926
Property and equipment, net	214,744	194,515
Goodwill	1,179,578	1,190,199
Intangible assets, net	319,251	340,631
Investment in subsidiaries	676,168	611,851
Other non-current assets	18,071	16,509
TOTAL ASSETS	3,040,941	3,032,978
LIABILITIES AND SHAREHOLDERS' EQUITY
Accounts payable, trade	45,858	64,888
Other Liabilities, Current	263,956	216,010
Long-term debt, net of current maturities	80,000	80,000
Income taxes payable	25,422	26,389
Intercompany liabilities	0	0
Other long-term liabilities	81,475	91,119
Redeemable noncontrolling interests	0	1,388
IAC shareholders' equity	2,544,230	2,553,184
Noncontrolling interests	0	0
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	3,040,941	3,032,978
Non-Guarantor Subsidiaries
ASSETS
Cash and cash equivalents	265,258	248,902	207,474	158,931
Marketable securities	0	0
Accounts receivable, net	84,786	87,160
Other current assets	52,875	45,204
Intercompany receivables	1,768,667	10,276,178
Property and equipment, net	70,371	71,881
Goodwill	484,737	425,955
Intangible assets, net	146,910	142,273
Investment in subsidiaries	0	0
Other non-current assets	122,358	109,912
TOTAL ASSETS	2,995,962	11,407,465
LIABILITIES AND SHAREHOLDERS' EQUITY
Accounts payable, trade	35,893	29,060
Other Liabilities, Current	239,449	238,003
Long-term debt, net of current maturities	0	0
Income taxes payable	12,270	13,446
Intercompany liabilities	0	0
Other long-term liabilities	83,471	45,950
Redeemable noncontrolling interests	64,147	56,738
IAC shareholders' equity	2,509,503	10,972,361
Noncontrolling interests	51,229	51,907
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	2,995,962	11,407,465
Total Eliminations
ASSETS
Cash and cash equivalents	0	0	0	0
Marketable securities	0	0
Accounts receivable, net	0	0
Other current assets	3,123	(1,037)
Intercompany receivables	(2,184,582)	(10,759,104)
Property and equipment, net	0	0
Goodwill	0	0
Intangible assets, net	0	0
Investment in subsidiaries	(5,053,733)	(13,525,545)
Other non-current assets	54	(68)
TOTAL ASSETS	(7,235,138)	(24,285,754)
LIABILITIES AND SHAREHOLDERS' EQUITY
Accounts payable, trade	0	0
Other Liabilities, Current	(14,866)	(1,652)
Long-term debt, net of current maturities	0	0
Income taxes payable	18,215	0
Intercompany liabilities	(2,184,582)	(10,759,104)
Other long-term liabilities	(172)	547
Redeemable noncontrolling interests	0	0
IAC shareholders' equity	(5,053,733)	(13,525,545)
Noncontrolling interests	0	0
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	(7,235,138)	(24,285,754)
IAC Consolidated
ASSETS
Cash and cash equivalents	678,725	749,977	807,196	704,153
Marketable securities	7,775	20,604
Accounts receivable, net	235,950	229,830
Other current assets	148,285	156,339
Intercompany receivables	0	0
Property and equipment, net	289,493	270,512
Goodwill	1,664,315	1,616,154
Intangible assets, net	466,161	482,904
Investment in subsidiaries	0	0
Other non-current assets	321,787	279,508
TOTAL ASSETS	3,812,491	3,805,828
LIABILITIES AND SHAREHOLDERS' EQUITY
Accounts payable, trade	83,294	98,314
Other Liabilities, Current	527,362	526,575
Long-term debt, net of current maturities	580,000	580,000
Income taxes payable	496,168	479,945
Intercompany liabilities	0	0
Other long-term liabilities	378,986	355,233
Redeemable noncontrolling interests	64,147	58,126
IAC shareholders' equity	1,631,305	1,655,728
Noncontrolling interests	51,229	51,907
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 3,812,491	$ 3,805,828