Business Acquisitions (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2015 USD ($) Business	Dec. 31, 2014 USD ($)
Business Acquisition [Line Items]
Goodwill	$ 5,111,662	$ 4,710,691
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Number of business acquired | Business	3
Cost of Acquired Entity Purchase Price	$ 590,000
Intangible Assets Other than Goodwill	213,000
Goodwill	424,000
Cost of Acquired Entity Transaction Costs	2,100
Finite lived intangible assets	192,000
Indefinite lived intangible assets	$ 21,000
Weighted average useful life	17 years
Series of Individually Immaterial Business Acquisitions [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Finite lived intangible assets	$ 153,000
Weighted average useful life	19 years
Series of Individually Immaterial Business Acquisitions [Member] | Software [Member]
Business Acquisition [Line Items]
Finite lived intangible assets	$ 39,000
Weighted average useful life	6 years