Other Comprehensive Income (Loss) - Changes in AOCI (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ (5.7)	$ (6.6)	$ (4.1)
Other comprehensive loss	(5.9)	0.9	(2.5)
Ending balance	(11.6)	(5.7)	(6.6)
Defined Benefit Plan [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(7.9)	(10.3)	(7.4)
Other comprehensive loss	(2.9)	2.4	(2.9)
Ending balance	(10.8)	(7.9)	(10.3)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	2.2	3.7	3.3
Other comprehensive loss	(3.0)	(1.5)	0.4
Ending balance	$ (0.8)	$ 2.2	$ 3.7