Restructuring - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	10 Months Ended	12 Months Ended	13 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2018
Initial Phase
Restructuring Cost and Reserve [Line Items]
Costs expected to incur		$ 16.0	$ 16.0	$ 16.0
Costs incurred				14.7
Initial Phase | Employee Severance and Benefits
Restructuring Cost and Reserve [Line Items]
Payments			2.6
Remaining liability for costs incurred	$ 5.4	5.7	5.7	5.7
Initial Phase | Consulting Services
Restructuring Cost and Reserve [Line Items]
Costs incurred	$ 5.4		9.3
Initial Phase | Minimum | Employee Severance and Benefits
Restructuring Cost and Reserve [Line Items]
Costs expected to incur		6.0	6.0	6.0
Initial Phase | Maximum | Employee Severance and Benefits
Restructuring Cost and Reserve [Line Items]
Costs expected to incur		8.0	8.0	8.0
ITS Plan
Restructuring Cost and Reserve [Line Items]
Costs incurred		6.4
Restructuring, amounts capitalized		33.2
Internal labor costs capitalized		2.9
ITS Plan | Minimum
Restructuring Cost and Reserve [Line Items]
Costs expected to incur		55.0	55.0	55.0
ITS Plan | Minimum | Qualify for Capitalization
Restructuring Cost and Reserve [Line Items]
Costs expected to incur		40.0	40.0	40.0
ITS Plan | Maximum
Restructuring Cost and Reserve [Line Items]
Costs expected to incur		60.0	60.0	60.0
ITS Plan | Maximum | Qualify for Capitalization
Restructuring Cost and Reserve [Line Items]
Costs expected to incur		$ 45.0	$ 45.0	$ 45.0