Property, Plant and Equipment, net (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Property, plant and equipment, net
Document Period End Date		Jun. 30, 2015
Gross property, plant and equipment	$ 560.0	$ 560.0		$ 520.3
Less: Accumulated depreciation and amortization	254.0	254.0		260.9
Net property, plant and equipment	306.0	306.0		259.4
Loss on disposal of property, plant and equipment	0.2	1.2	$ 0.0
Net capitalized turnaround costs:
Beginning balance		16.7	22.7
Additions		30.7	0.3
Depreciation		(5.0)	(3.2)
Ending balance	42.4	42.4	$ 19.8
Land
Property, plant and equipment, net
Gross property, plant and equipment	1.6	1.6		1.6
Buildings and improvements
Property, plant and equipment, net
Gross property, plant and equipment	14.4	14.4		8.1
Machinery and equipment
Property, plant and equipment, net
Gross property, plant and equipment	530.0	530.0		401.4
Construction in progress
Property, plant and equipment, net
Gross property, plant and equipment	$ 14.0	$ 14.0		$ 109.2