Shareholders' Equity - Components of Accumulated Other Comprehensive Loss, Net of Tax (Parenthetical) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Translation gain on derivative instruments, net of income taxes of $(9.0) and $(9.1), respectively
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, income taxes	$ (9.0)	$ (9.1)
Defined benefit pension plans and Retiree health care plan | Defined benefit pension plans, net of income taxes of $(35.2) and $(30.9), respectively
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, income taxes	(35.2)	(30.9)
Defined benefit pension plans and Retiree health care plan | Retiree health care plan, net of income taxes of $2.2 and $1.6, respectively
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, income taxes	$ 2.2	$ 1.6