Foreign Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Foreign operations data
Revenues	$ 401.4	$ 397.2	$ 365.8	$ 286.6	$ 356.6	$ 353.2	$ 338.9	$ 272.3	$ 1,451.0	$ 1,321.0	$ 1,243.2
Identifiable assets	6,937.5				6,549.6				6,937.5	6,549.6	6,055.4
Foreign Operations (Textual) [Abstract]
Maximum percentage of consolidated revenues derive from any individual foreign country									10.00%
Percentage of company's identifiable assets	10.00%								10.00%
Foreign [Member]
Foreign operations data
Revenues									346.2	332.1	279.8
Identifiable assets	2,133.9				2,200.1				2,133.9	2,200.1	1,897.9
United States [Member]
Foreign operations data
Revenues									1,104.8	988.9	963.4
Identifiable assets	$ 4,803.6				$ 4,349.5				$ 4,803.6	$ 4,349.5	$ 4,157.5