Restructuring Expenses (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Restructuring Reserve [Roll Forward]
Restructuring Reserve at Beginning of Year	$ 1.7	$ 0.7	$ 2.2
Restructuring Reserve, Expenses Incurred	7.2	3.6	1.1
Restructuring Reserve, Paid	4.0	2.6	2.6
Restructuring Reserve at End of Year	4.9	1.7	0.7
Employee Termination Costs [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve at Beginning of Year	0.7	0.6	1.6
Restructuring Reserve, Expenses Incurred	5.1	2.1	1.1
Restructuring Reserve, Paid	3.2	2.0	2.1
Restructuring Reserve at End of Year	2.6	0.7	0.6
Early Lease Termination Costs [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve at Beginning of Year	1.0	0.1	0.6
Restructuring Reserve, Expenses Incurred	2.0	1.4	0
Restructuring Reserve, Paid	0.7	0.5	0.5
Restructuring Reserve at End of Year	2.3	1.0	0.1
Other Associated Costs [Member]
Restructuring Reserve [Roll Forward]
Restructuring Reserve at Beginning of Year	0	0	0
Restructuring Reserve, Expenses Incurred	0.1	0.1	0
Restructuring Reserve, Paid	0.1	0.1	0
Restructuring Reserve at End of Year	$ 0	$ 0	$ 0