Foreign Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended									12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Canada [Member]	Dec. 31, 2011 Canada [Member]	Dec. 31, 2009 Canada [Member]	Dec. 31, 2012 Germany [Member]	Dec. 31, 2011 Germany [Member]	Dec. 31, 2010 Germany [Member]	Dec. 31, 2012 Foreign [Member]	Dec. 31, 2011 Foreign [Member]	Dec. 31, 2010 Foreign [Member]	Dec. 31, 2012 United States [Member]	Dec. 31, 2011 United States [Member]	Dec. 31, 2010 United States [Member]
Foreign operations data
Revenues	$ 331.7	$ 331.9	$ 323.1	$ 256.5	$ 330.0	$ 315.2	$ 296.8	$ 249.4	$ 1,243.2	$ 1,191.4	$ 1,114.0							$ 279.8	$ 278.6	$ 270.7	$ 963.4	$ 912.8	$ 843.3
Identifiable assets	$ 6,055.4				$ 5,857.5				$ 6,055.4	$ 5,857.5	$ 5,442.4							$ 1,897.9	$ 1,766.6	$ 1,806.8	$ 4,157.5	$ 4,090.9	$ 3,635.6
Foreign Operations (Textual) [Abstract]
Maximum percentage of consolidated revenues derive from any individual foreign country																		10.00%	10.00%	10.00%
Percentage of company's identifiable assets												8.00%	8.00%	10.00%	7.00%	9.00%	10.00%