Commitments and Contingencies, Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Timing of final feasibility study	12 months
Accrual for Environmental Loss Contingencies, Gross, Fiscal Year Maturity
Operating Leases, Rent Expense		$ 8.2	$ 7.9
Environmental accrual	$ 17.0	$ 16.9	$ 16.6	$ 17.2
Expected period related to remediation expenditures for environmental contingencies	30 years
Estimated environmental contingency loss exposure in excess of current accrual	$ 11.6
Time period within which Company's recorded estimate of its obligation may change	12 months