Employee Benefit Plans - Narrative (Details) $ in Millions		3 Months Ended		9 Months Ended
	Sep. 20, 2018 USD ($) Employee	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)
Components of periodic benefit costs
Other income (expense) - net		$ (5.7)	$ (3.1)	$ (8.6)	$ (4.0)
U.S. Pension Plans
Components of periodic benefit costs
Defined benefit plan obligation transfer	$ 18.6
Number of retirees and beneficiaries | Employee	622
Pension Settlement Charge | Reclassification out of Accumulated Other Comprehensive Income
Components of periodic benefit costs
Other income (expense) - net		$ (4.5)		$ (4.5)
Pension Settlement Charge | Reclassification out of Accumulated Other Comprehensive Income | U.S. Pension Plans
Components of periodic benefit costs
Other income (expense) - net	$ 4.5