Goodwill and Identifiable Intangible Assets, Net (Details 2) (USD $) In Thousands, unless otherwise specified					9 Months Ended				9 Months Ended				9 Months Ended				9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Customer relationships	Dec. 31, 2012 Customer relationships	Sep. 30, 2013 Customer relationships Minimum	Sep. 30, 2013 Customer relationships Maximum	Sep. 30, 2013 Backlog	Dec. 31, 2012 Backlog	Sep. 30, 2013 Backlog Minimum	Sep. 30, 2013 Backlog Maximum	Sep. 30, 2013 Noncompete agreements	Dec. 31, 2012 Noncompete agreements	Sep. 30, 2013 Noncompete agreements Minimum	Sep. 30, 2013 Noncompete agreements Maximum	Sep. 30, 2013 Tradenames	Dec. 31, 2012 Tradenames	Sep. 30, 2013 Tradenames Minimum	Sep. 30, 2013 Tradenames Maximum
Identifiable Intangible Assets, Net
Estimated Useful Lives in Years					1 year	15 years			1 year	2 years			2 years	7 years			2 years	25 years
Gross Book Value	$ 73,504	$ 73,504	$ 40,404	$ 40,404			$ 6,515	$ 6,515			$ 2,890	$ 2,890			$ 23,695	$ 23,695
Accumulated Amortization	$ (34,397)	$ (28,989)	$ (19,639)	$ (15,579)			$ (6,515)	$ (6,375)			$ (2,594)	$ (2,380)			$ (5,649)	$ (4,655)