Goodwill and Acquired Intangible Assets, Net (Tables)

9 Months Ended

Sep. 30, 2015

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets and Goodwill [Table Text Block]

A summary of acquired intangible assets and goodwill activity for the nine months ended September 30, 2015 is presented below:

(in thousands)	Acquired Intangible Assets			Goodwill			Total Intangible Assets
Balance as of December 31, 2014	$	158,267		$	599,863		$	758,130
Increases (Decreases):
Acquisitions	50,497			134,080			184,577
Amortization	(17,707		)	—			(17,707		)
Other (primarily changes in foreign currency exchange rates)	(17,083		)	(47,584		)	(64,667		)
Balance as of September 30, 2015	$	173,974		$	686,359		$	860,333