Goodwill and Intangible Assets Acquisitions (Details) (USD $)				12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Series of Individually Immaterial Business Acquisitions [Member]	Dec. 31, 2013 Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Business Acquisition, Cost of Acquired Entity, Purchase Price				$ 37,000,000
Business Acquisition, Cost of Acquired Entity, Cash Paid				24,000,000
Business Acquisition, Contingent Consideration, at Fair Value				13,000,000
Business Acquisition, Purchase Price Allocation, Intangible Assets Other than Goodwill					21,000,000
Business Acquisition, Purchase Price Allocation, Goodwill Amount	$ 359,759,000	$ 361,979,000	$ 335,601,000		$ 29,000,000