Business Combinations - Table 3 (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net Cash Paid For All Acquisitions During Each Period Presented
Fair value of assets acquired	$ 15.6	$ 2.1	$ 0.7
Goodwill	13.7	0	1.4
Fair value of liabilities assumed	(0.4)	0	0
Noncompete agreements	0	1.0	2.8
Net cash paid for acquisitions	$ 28.9	$ 3.1	$ 4.9