Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Trade accounts payable	$ 149.6	$ 228.1
Accrued wages, salaries and employee benefits	45.0	41.4
Operating Lease, Liability, Current	13.9
Accrued interest	13.3	14.7
Accrued utilities	8.6	6.9
Accrued discounts and allowances	6.6	8.1
Current liability for pension and other postretirement employee benefits	7.4	7.4
Accrued taxes other than income taxes payable	7.1	6.2
Other	11.0	14.2
Accounts payable and accrued liabilities	262.5	327.0
Accrued Liabilities, Current	$ 6.3	$ 57.1