Property, plant and equipment, net (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment
Total cost	$ 961.3	$ 919.4
Less: accumulated depreciation	(522.8)	(496.6)
Property, plant and equipment, net	438.5	422.8	$ 437.5
Machinery and equipment
Property, Plant and Equipment
Total cost	792.5	764.0
Buildings and leasehold equipment
Property, Plant and Equipment
Total cost	115.0	111.2
Land and land improvements
Property, Plant and Equipment
Total cost	18.0	17.9
Construction in progress
Property, Plant and Equipment
Total cost	35.8	26.3
Wickliffe, Kentucky Manufacturing Facility | Machinery and equipment
Property, Plant and Equipment
Less: accumulated depreciation	(62.5)	(64.0)
Property, plant and equipment, net	7.6	9.2
Waynesboro, Georgia Manufacturing Facility | Machinery and equipment
Property, Plant and Equipment
Less: accumulated depreciation	(0.2)	0.0
Property, plant and equipment, net	5.7	0.4
Waynesboro, Georgia Manufacturing Facility | Construction in progress
Property, Plant and Equipment
Property, plant and equipment, net	$ 2.1	3.4
DeRidder, Louisiana Manufacturing Facility | Machinery and equipment
Property, Plant and Equipment
Less: accumulated depreciation		(15.5)
Property, plant and equipment, net		$ 17.8