Other (Expense) Income, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other Income and Expenses [Abstract]
Interest income	$ 0.2	$ 0.1	$ 0.5	$ 0.2
Net periodic postretirement benefit cost relating to Salaried VEBA	(1.6)	(1.4)	(4.9)	(4.5)
Realized gain on available for sale securities	0.9	1.6	3.0	4.3
Unrealized gain (loss) on equity securities	0.1	0.1	0.6	(0.3)
All other (expense) income, net	(0.4)	0.3	0.4	0.6
Other (expense) income, net	$ (0.8)	$ 0.7	$ (0.4)	$ 0.3