Information About Revenue and Geographic Areas (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
Summary of revenue by product line and geographic region
Total	$ 363,661		$ 228,207		$ 688,366		$ 416,663
United States [Member]
Summary of revenue by product line and geographic region
Total	224,277		147,253		425,680		268,102
Other Americas [Member]
Summary of revenue by product line and geographic region
Total	26,857	[1]	15,047	[1]	51,033	[1]	27,056	[1]
Americas [Member]
Summary of revenue by product line and geographic region
Total	251,134		162,300		476,713		295,158
EMEA [Member]
Summary of revenue by product line and geographic region
Total	84,691	[2]	50,057	[2]	159,848	[2]	92,902	[2]
APAC [Member]
Summary of revenue by product line and geographic region
Total	27,836	[3]	15,850	[3]	51,805	[3]	28,603	[3]
Talent Solutions [Member]
Summary of revenue by product line and geographic region
Total	205,092		121,592		389,376		224,152
Marketing Solutions [Member]
Summary of revenue by product line and geographic region
Total	85,593		63,105		160,389		111,055
Premium Subscriptions [Member]
Summary of revenue by product line and geographic region
Total	$ 72,976		$ 43,510		$ 138,601		$ 81,456

[1] Canada, Latin America and South America

[2] Europe, the Middle East and Africa (“EMEA”)

[3] Asia-Pacific (“APAC”)