Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Accumulated Other Comprehensive Loss [Abstract]
Pension and post retirement benefit plan adjustment, net of tax	$ (153.7)	$ (95.6)	$ (71.7)
Cumulative translation adjustment	2.5	14.6	2.7
Unrealized gain on investment, net of tax	1.0	0.5	0.5
Cash flow hedge loss, net of tax	(0.2)	(0.8)	(0.3)
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (150.4)	$ (81.3)