Acquisitions Acquisitions Narrative (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Business Acquisition
Number of Businesses Acquired	6	8
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	$ 137.0	$ 67.0
IAN
Business Acquisition
Number of Businesses Acquired	4	7
CMG
Business Acquisition
Number of Businesses Acquired	2	1