SEGMENT INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment reporting information
Revenue	$ 799,411	$ 680,612	$ 1,541,660	$ 1,321,212
Operating income	106,696	97,476	191,247	160,241
Operating Income Before Amortization	140,902	123,722	253,652	214,994
Depreciation	17,036	12,225	31,052	24,340
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	140,902	123,722	253,652	214,994
Non-Cash Compensation Expense	(11,820)	(20,441)	(24,483)	(41,907)
Amortization of Intangibles	(18,137)	(5,805)	(32,215)	(12,846)
Acquisition-related Contingent Consideration Fair Value Adjustment	(4,249)		(5,707)	0
Operating income	106,696	97,476	191,247	160,241
Search and Applications
Segment reporting information
Revenue	427,449	348,762	824,641	691,960
Operating income	89,346	74,067	176,329	147,557
Operating Income Before Amortization	96,007	74,079	189,656	147,579
Depreciation	6,413	3,385	10,278	6,676
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	96,007	74,079	189,656	147,579
Non-Cash Compensation Expense	0	(9)	(3)	(17)
Amortization of Intangibles	(6,661)	(3)	(13,324)	(5)
Operating income	89,346	74,067	176,329	147,557
Match
Segment reporting information
Revenue	194,320	178,418	383,182	352,693
Operating income	58,387	57,099	99,346	87,005
Operating Income Before Amortization	67,608	62,645	113,911	99,973
Depreciation	4,776	3,742	9,453	7,279
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	67,608	62,645	113,911	99,973
Non-Cash Compensation Expense	(363)	(556)	(206)	(1,463)
Amortization of Intangibles	(4,609)	(4,990)	(8,652)	(11,505)
Acquisition-related Contingent Consideration Fair Value Adjustment	(4,249)		(5,707)
Operating income	58,387	57,099	99,346	87,005
Local
Segment reporting information
Revenue	84,734	84,505	159,679	161,624
Operating income	(3,958)	11,670	(7,361)	15,459
Operating Income Before Amortization	1,968	11,832	967	15,782
Depreciation	2,707	2,475	5,053	5,276
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	1,968	11,832	967	15,782
Amortization of Intangibles	(5,926)	(162)	(8,328)	(323)
Operating income	(3,958)	11,670	(7,361)	15,459
Media
Segment reporting information
Revenue	58,014	38,368	103,329	54,279
Operating income	(4,028)	(7,305)	(12,856)	(13,974)
Operating Income Before Amortization	(3,522)	(6,789)	(11,896)	(13,190)
Depreciation	524	295	1,047	474
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	(3,522)	(6,789)	(11,896)	(13,190)
Non-Cash Compensation Expense	(213)	(236)	(418)	(504)
Amortization of Intangibles	(293)	(280)	(542)	(280)
Operating income	(4,028)	(7,305)	(12,856)	(13,974)
Other
Segment reporting information
Revenue	35,005	30,629	71,050	60,835
Operating income	(4,097)	(2,182)	(7,319)	(3,896)
Operating Income Before Amortization	(3,418)	(1,755)	(5,917)	(3,153)
Depreciation	348	257	650	501
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	(3,418)	(1,755)	(5,917)	(3,153)
Non-Cash Compensation Expense	(31)	(57)	(33)	(10)
Amortization of Intangibles	(648)	(370)	(1,369)	(733)
Operating income	(4,097)	(2,182)	(7,319)	(3,896)
Total Eliminations
Segment reporting information
Revenue	(111)	(70)	(221)	(179)
Corporate
Segment reporting information
Operating income	(28,954)	(35,873)	(56,892)	(71,910)
Operating Income Before Amortization	(17,741)	(16,290)	(33,069)	(31,997)
Depreciation	2,268	2,071	4,571	4,134
Reconciliation of Operating Income Before Amortization to operating income (loss) for the entity's reportable segments
Operating Income Before Amortization	(17,741)	(16,290)	(33,069)	(31,997)
Non-Cash Compensation Expense	(11,213)	(19,583)	(23,823)	(39,913)
Operating income	$ (28,954)	$ (35,873)	$ (56,892)	$ (71,910)