Acquisitions - Intangible Assets Acquired (Details) (RFPD and Nu Horizons [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 Y
Intangible Assets Acquired As Part Of Business Combination [Line Items]
Business Acquisition, Purchase Price Allocation, Identifiable Intangible Assets	$ 90,900
Customer Relationships [Member]
Intangible Assets Acquired As Part Of Business Combination [Line Items]
Business Acquisition, Purchase Price Allocation, Identifiable Intangible Assets	35,400
Weighted Average Useful Life	8
Trade Names [Member]
Intangible Assets Acquired As Part Of Business Combination [Line Items]
Business Acquisition, Purchase Price Allocation, Identifiable Intangible Assets	49,000
Other Intangible Assets [Member]
Intangible Assets Acquired As Part Of Business Combination [Line Items]
Business Acquisition, Purchase Price Allocation, Identifiable Intangible Assets	$ 6,500	[1]
Acquired Finite-lived Intangible Asset, Useful Life, Minimum	1
Acquired Finite-lived Intangible Asset, Useful Life, Maximum	3

[1] Consists of non-competition agreements and sales backlog with useful lives ranging from one to three years.