Summary of Significant Acquisitions (Detail) (USD $) In Thousands, unless otherwise specified				12 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2011 Interclick	Dec. 14, 2011 Interclick	Dec. 31, 2013 Other Acquisitions	Dec. 31, 2011 Other Acquisitions	Dec. 31, 2012 All Acquisitions Business Combinations	Dec. 31, 2013 Tumblr	Jun. 19, 2013 Tumblr
Business Acquisition [Line Items]
Purchase Price				$ 258,501		$ 279,000	$ 72,000	$ 7,000	$ 990,211
Goodwill	4,679,648	3,826,749	3,900,752	171,641	171,641	186,000	49,000	5,000	751,765	751,765
Amortizable Intangibles				$ 79,000		$ 76,000	$ 26,000		$ 263,000