Goodwill and Acquired Intangible Assets, NET (Tables)

12 Months Ended

Dec. 31, 2012

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, 2012 and 2011:

	As of December 31, 2012					As of December 31, 2011
(in thousands)	Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
Customer relationships	$	172,280	$	(120,117	)	$	178,572	$	(111,589	)
Trademarks and trade names	44,226		(13,742		)	43,401		(11,232		)
Software	5,914		(5,645		)	5,771		(5,233		)
Non-compete agreements	1,798		(1,325		)	1,253		(1,065		)
Total	$	224,218	$	(140,829	)	$	228,997	$	(129,119	)

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, 2011 and 2012:

(in thousands)	Acquired Intangible Assets			Goodwill			Total Intangible Assets
Balance as of January 1, 2011	$	95,819		$	445,713		$	541,532
Increases (decreases):
2011 acquisitions	28,616			56,855			85,471
Amortization	(22,223		)	—			(22,223		)
Other (primarily changes in foreign currency exchange rates)	(2,334		)	(13,940		)	(16,274		)
Balance as of December 31, 2011	99,878			488,628			588,506
Increases (decreases):
2012 acquisitions	10,856			12,812			23,668
Impairment	(5,235		)	(23,505		)	(28,740		)
Amortization	(22,129		)	—			(22,129		)
Other (primarily changes in foreign currency exchange rates)	19			3,825			3,844
Balance as of December 31, 2012	$	83,389		$	481,760		$	565,149