Acquisitions (Details Textual) (Maverick [Member], USD $)	9 Months Ended				9 Months Ended
	Sep. 30, 2011	Sep. 30, 2012 Customer Relationships [Member]	Sep. 30, 2012 Non-Compete Agreements [Member]	Sep. 30, 2012 Trade Name [Member]	Sep. 30, 2012 Intellectual Property [Member]
Acquisitions (Textual) [Abstract]
Revenue included in the consolidated statement of operations	$ 27,700,000
Aggregate purchase price	186,300,000
Additional depreciation	8,100,000
Amortization expense, for the amortization of intangible assets	1,300,000
Interest expense	6,400,000
Other intangible assets, amortizable		25,300,000	3,600,000		380,000
Other intangible assets, amortization period, years		15 years	5 years		15 years
Other intangible assets, indefinite life				$ 170,000