Commitments and Contingencies - Environmental Matters (Details) $ in Millions	6 Months Ended	30 Months Ended
	Jun. 30, 2020 USD ($) defendant facility	Jun. 30, 2020 USD ($)
Loss Contingencies [Line Items]
Number of facilities owned | facility	13
U.S.
Loss Contingencies [Line Items]
Number of facilities owned | facility	4
Number Of Facilities, Capital Expenditures Could Exceed Or Be Lower Than Current Expectations | facility	3
Settled with the U.S. government | Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Number of carbon black producers (defendants) | defendant	5
Period to install pollution control technology	5 years
Civil penalty	$ 0.8
Cost of environmental mitigation projects	0.6
Settled with the U.S. government | Unfavorable Regulatory Action | U.S.
Loss Contingencies [Line Items]
Capital expenditures for installments, payments		$ 98.0
Settled with the U.S. government | Unfavorable Regulatory Action | U.S. | Minimum
Loss Contingencies [Line Items]
Estimated capital expenditures to be incurred for installments	230.0	230.0
Settled with the U.S. government | Unfavorable Regulatory Action | U.S. | Maximum
Loss Contingencies [Line Items]
Estimated capital expenditures to be incurred for installments	$ 270.0	$ 270.0