Goodwill and Identifiable Intangible Assets, Net (Details 2) (USD $) In Thousands, unless otherwise specified					3 Months Ended				3 Months Ended				3 Months Ended				3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Customer relationships	Dec. 31, 2012 Customer relationships	Mar. 31, 2013 Customer relationships Minimum	Mar. 31, 2013 Customer relationships Maximum	Mar. 31, 2013 Backlog	Dec. 31, 2012 Backlog	Mar. 31, 2013 Backlog Minimum	Mar. 31, 2013 Backlog Maximum	Mar. 31, 2013 Noncompete agreements	Dec. 31, 2012 Noncompete agreements	Mar. 31, 2013 Noncompete agreements Minimum	Mar. 31, 2013 Noncompete agreements Maximum	Mar. 31, 2013 Tradenames	Dec. 31, 2012 Tradenames	Mar. 31, 2013 Tradenames Minimum	Mar. 31, 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	$ (30,918)	$ (28,989)	$ (16,934)	$ (15,579)			$ (6,515)	$ (6,375)			$ (2,482)	$ (2,380)			$ (4,987)	$ (4,655)