Restructuring and Other Expense - Components of Restructuring and Other Expense for Continuing Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Restructuring Expense:
Severance and related	$ 1.4	$ 0.6
Loss on abandonment of unused property, plant and equipment	1.6	0.0
Other	(2.1)	0.0
Total restructuring	0.9	0.6
Other Expense:
Pension settlement/curtailment (Note 9)	1.1	2.9
Asset disposals / write down	0.0	0.1
Other	(0.1)	4.0
Total other	1.0	7.0
Total	$ 1.9	$ 7.6