Restructuring and Asset Impairments - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 27.2	$ 23.4	$ 9.4
Asset impairment expense	0.1	96.9	$ 15.3
Fixed Assets
Restructuring Cost and Reserve [Line Items]
Asset impairment expense		13.8
Enterprise Resource Planning Platform
Restructuring Cost and Reserve [Line Items]
Asset impairment expense		58.6
SAP and Other Information Technology Assets
Restructuring Cost and Reserve [Line Items]
Asset impairment expense		18.6
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring expense		$ 2.3
Employee Severance | Chief Financial Officer
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 2.8