Retirement Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Components of net periodic benefit cost (income)
Service cost	$ 0.2	$ 0.2	$ 0.6	$ 0.6
Interest cost	1.2	1.3	3.6	3.9
Expected return on plan assets	(1.7)	(1.9)	(5.1)	(5.7)
Amortization of unrecognized loss	0.2	0.1	0.6	0.3
Net periodic pension (income) cost before settlement and special termination benefits expense	(0.1)	(0.3)	(0.3)	(0.9)
Settlement expense	0.5		0.5
Special termination benefits expense	0.1	0.2	0.2	0.6
Net periodic benefit expense (income)	0.5	(0.1)	0.4	(0.3)
Anticipated contribution to the Non-qualified Plan in 2012	2.4		2.4
Contributions to the Non-qualified Plan in the current fiscal period	1.7		1.7
Discount rate utilized for revaluation (as a percent)	3.75%		3.75%		4.50%
Recognized loss due to settlement and re-measurement through other comprehensive income	3.7		3.7
Remaining Qualified Plan liabilities at time of settlement	$ 92.4		$ 92.4