SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Segment reporting information
Revenue	$ 714,470	$ 516,884	$ 2,035,682	$ 1,462,501
Operating Income (Loss)	78,033	46,740	238,274	142,307
Operating Income Before Amortization	106,596	74,163	321,590	217,555
Depreciation	13,150	17,484	37,490	43,373
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	106,596	74,163	321,590	217,555
Non-cash compensation expense	(23,351)	(22,885)	(65,258)	(66,053)
Amortization of Intangibles	(5,212)	(4,538)	(18,058)	(9,195)
Operating income	78,033	46,740	238,274	142,307
Reconciliation of segment assets to total assets
Indefinite-Lived Intangible Assets	388,031		388,031		351,488
Definite-Lived Intangible Assets	103,454		103,454		26,619
Search and Applications
Segment reporting information
Revenue	370,227	258,875	1,062,187	731,054
Operating Income (Loss)	69,036	45,508	216,593	144,780
Operating Income Before Amortization	69,192	46,280	216,771	145,742
Depreciation	3,343	9,824	10,019	21,389
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	69,192	46,280	216,771	145,742
Non-cash compensation expense	(9)	(4)	(26)	210
Amortization of Intangibles	(147)	(768)	(152)	(1,172)
Operating income	69,036	45,508	216,593	144,780
Match
Segment reporting information
Revenue	178,190	132,328	530,883	360,354
Operating Income (Loss)	56,078	36,677	143,083	101,105
Operating Income Before Amortization	59,980	40,207	159,953	107,530
Depreciation	4,502	2,481	11,781	7,059
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	59,980	40,207	159,953	107,530
Non-cash compensation expense	(560)	(423)	(2,023)	(423)
Amortization of Intangibles	(3,342)	(3,107)	(14,847)	(6,002)
Operating income	56,078	36,677	143,083	101,105
Local
Segment reporting information
Revenue	84,314	80,124	245,938	231,465
Operating Income (Loss)	7,343	7,324	22,802	22,484
Operating Income Before Amortization	7,817	7,767	23,599	23,836
Depreciation	2,463	2,738	7,739	7,325
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	7,817	7,767	23,599	23,836
Amortization of Intangibles	(474)	(443)	(797)	(1,352)
Operating income	7,343	7,324	22,802	22,484
Media
Segment reporting information
Revenue	52,736	18,692	107,015	51,811
Operating Income (Loss)	(13,178)	(2,837)	(27,152)	(10,545)
Operating Income Before Amortization	(12,236)	(2,651)	(25,426)	(10,301)
Depreciation	424	153	898	546
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	(12,236)	(2,651)	(25,426)	(10,301)
Non-cash compensation expense	(62)	(186)	(566)	(241)
Amortization of Intangibles	(880)		(1,160)	(3)
Operating income	(13,178)	(2,837)	(27,152)	(10,545)
Other
Segment reporting information
Revenue	29,064	27,023	89,899	88,442
Operating Income (Loss)	(2,685)	(1,648)	(6,581)	(3,891)	(6,581)
Operating Income Before Amortization	(2,259)	(1,339)	(5,412)	(2,970)
Depreciation	286	209	787	623
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	(2,259)	(1,339)	(5,412)	(2,970)
Non-cash compensation expense	(57)	(89)	(67)	(255)
Amortization of Intangibles	(369)	(220)	(1,102)	(666)
Operating income	(2,685)	(1,648)	(6,581)	(3,891)	(6,581)
Inter-segment elimination
Segment reporting information
Revenue	(61)	(158)	(240)	(625)
Corporate
Segment reporting information
Operating Income (Loss)	(38,561)	(38,284)	(110,471)	(111,626)
Operating Income Before Amortization	(15,898)	(16,101)	(47,895)	(46,282)
Depreciation	2,132	2,079	6,266	6,431
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	(15,898)	(16,101)	(47,895)	(46,282)
Non-cash compensation expense	(22,663)	(22,183)	(62,576)	(65,344)
Operating income	$ (38,561)	$ (38,284)	$ (110,471)	$ (111,626)