Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
NOL and credit carryforwards	$ 118.6	$ 141.0
Pension, other postretirement and postemployment benefits	31.1	36.5
Payroll and compensation	16.3	15.0
Legal, environmental and self-insurance accruals	35.9	22.6
Working capital accruals	17.0	17.1
Other	9.8	8.4
Total deferred tax assets	228.7	240.6
Valuation allowance	(89.8)	(92.0)
Net deferred tax assets	138.9	148.6
Deferred tax liabilities:
Intangible assets recorded in acquisitions	79.4	65.2
Basis difference in affiliates	19.8	16.3
Accelerated depreciation	13.3	11.9
Deferred income	20.2	29.4
Other	16.8	11.1
Total deferred tax liabilities	149.5	133.9
Total deferred tax liabilities	$ (10.6)
Total deferred tax assets		$ 14.7