SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment reporting information
Revenue	$ 756,872	$ 714,470	$ 2,298,532	$ 2,035,682
Operating income	122,004	78,033	313,251	238,274
Operating Income Before Amortization	150,033	106,596	403,685	321,590
Depreciation	13,489	13,150	44,541	37,490
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	150,033	106,596	403,685	321,590
Non-Cash Compensation Expense	(14,365)	(23,351)	(38,848)	(65,258)
Amortization of Intangibles	(13,032)	(5,212)	(45,247)	(18,058)
Acquisition-related Contingent Consideration Fair Value Adjustments	(632)		(6,339)	0
Operating income	122,004	78,033	313,251	238,274
Search and Applications
Segment reporting information
Revenue	407,291	370,227	1,231,932	1,062,187
Operating income	87,756	69,036	264,085	216,593
Operating Income Before Amortization	94,647	69,192	284,303	216,771
Depreciation	3,865	3,343	14,143	10,019
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	94,647	69,192	284,303	216,771
Non-Cash Compensation Expense	0	(9)	(3)	(26)
Amortization of Intangibles	(6,891)	(147)	(20,215)	(152)
Operating income	87,756	69,036	264,085	216,593
Match
Segment reporting information
Revenue	201,069	178,190	584,251	530,883
Operating income	64,823	56,078	164,169	143,083
Operating Income Before Amortization	68,447	59,980	182,358	159,953
Depreciation	4,985	4,502	14,438	11,781
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	68,447	59,980	182,358	159,953
Non-Cash Compensation Expense	(336)	(560)	(542)	(2,023)
Amortization of Intangibles	(2,656)	(3,342)	(11,308)	(14,847)
Acquisition-related Contingent Consideration Fair Value Adjustments	(632)		(6,339)
Operating income	64,823	56,078	164,169	143,083
Local
Segment reporting information
Revenue	62,805	84,314	222,484	245,938
Operating income	9,853	7,343	2,492	22,802
Operating Income Before Amortization	12,417	7,817	13,384	23,599
Depreciation	1,346	2,463	6,399	7,739
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	12,417	7,817	13,384	23,599
Amortization of Intangibles	(2,564)	(474)	(10,892)	(797)
Operating income	9,853	7,343	2,492	22,802
Media
Segment reporting information
Revenue	50,974	52,736	154,303	107,015
Operating income	(8,475)	(13,178)	(21,331)	(27,152)
Operating Income Before Amortization	(7,984)	(12,236)	(19,880)	(25,426)
Depreciation	526	424	1,573	898
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	(7,984)	(12,236)	(19,880)	(25,426)
Non-Cash Compensation Expense	(219)	(62)	(637)	(566)
Amortization of Intangibles	(272)	(880)	(814)	(1,160)
Operating income	(8,475)	(13,178)	(21,331)	(27,152)
Other
Segment reporting information
Revenue	35,085	29,064	106,135	89,899
Operating income	(2,529)	(2,685)	(9,848)	(6,581)
Operating Income Before Amortization	(1,880)	(2,259)	(7,797)	(5,412)
Depreciation	360	286	1,010	787
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	(1,880)	(2,259)	(7,797)	(5,412)
Non-Cash Compensation Expense	0	(57)	(33)	(67)
Amortization of Intangibles	(649)	(369)	(2,018)	(1,102)
Operating income	(2,529)	(2,685)	(9,848)	(6,581)
Total Eliminations
Segment reporting information
Revenue	(352)	(61)	(573)	(240)
Corporate
Segment reporting information
Operating income	(29,424)	(38,561)	(86,316)	(110,471)
Operating Income Before Amortization	(15,614)	(15,898)	(48,683)	(47,895)
Depreciation	2,407	2,132	6,978	6,266
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	(15,614)	(15,898)	(48,683)	(47,895)
Non-Cash Compensation Expense	(13,810)	(22,663)	(37,633)	(62,576)
Operating income	$ (29,424)	$ (38,561)	$ (86,316)	$ (110,471)