Goodwill and Intangible Assets (Details 1) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Summary of the components of intangible assets
Gross Carrying Amount	$ 132,987	$ 132,104
Accumulated Amortization	47,278	38,291
Customer relationships [Member]
Summary of the components of intangible assets
Gross Carrying Amount	119,373	118,567
Accumulated Amortization	42,764	34,960
Non-compete agreements [Member]
Summary of the components of intangible assets
Gross Carrying Amount	3,888	3,888
Accumulated Amortization	3,152	2,902
Trade name [Member]
Summary of the components of intangible assets
Gross Carrying Amount	8,326	8,249
Accumulated Amortization	993	410
Developed technology [Member]
Summary of the components of intangible assets
Gross Carrying Amount	1,400	1,400
Accumulated Amortization	$ 369	$ 19