Goodwill and Acquired Intangible Assets, Net (Tables)

12 Months Ended

Dec. 31, 2016

Goodwill and Acquired Intangible Assets Net [Abstract]

Schedule of Finite-Lived Intangible Assets [Table Text Block]

The following table summarizes intangible assets as of December 31, 2016 and 2015:

	As of December 31, 2016					As of December 31, 2015
(in thousands)	Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
Customer relationships	$	199,842	$	(107,820	)	$	174,219	$	(96,144	)
Trademarks and trade names	53,396		(21,598		)	55,706		(19,323		)
Software	58,696		(18,291		)	65,634		(13,820		)
Non-compete agreements	3,744		(2,638		)	3,508		(1,808		)
Total	$	315,678	$	(150,347	)	$	299,067	$	(131,095	)

Schedule of Intangible Assets and Goodwill [Table Text Block]

The following table summarizes the goodwill and amortizable intangible assets activity for the years ended December 31, 2016 and 2015:

(in thousands)	Acquired Intangible Assets			Goodwill			Total Intangible Assets
Balance as of January 1, 2015	$	158,267		$	599,863		$	758,130
Increases (decreases):
Acquisitions	50,497			143,461			193,958
Amortization	(23,879		)	—			(23,879		)
Other (primarily changes in foreign currency exchange rates)	(16,913		)	(58,146		)	(75,059		)
Balance as of December 31, 2015	167,972			685,178			853,150
Increases (decreases):
Acquisitions	33,921			29,871			63,792
Amortization	(25,503		)	—			(25,503		)
Other (primarily changes in foreign currency exchange rates)	(11,059		)	(25,336		)	(36,395		)
Balance as of December 31, 2016	$	165,331		$	689,713		$	855,044