Income Taxes Reconciliation of deferred taxes (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Accrued liabilities	$ 23.0	$ 18.0
Pension and post-retirement benefits	5.0	7.0
Share-based compensation	4.0	5.0
Benefit of capital loss and NOL carryovers	9.0	28.0
Other	12.0	8.0
Inventory	7.0	7.0
Market value write down of ARS	0.0	3.0
Deferred Tax Liabilities, Leasing Arrangements	5.0	6.0
Valuation Allowance, Amount	(10.0)	(11.0)
Deferred Tax Assets, Net of Valuation Allowance	55.0	71.0
Deferred Tax Assets, Net	65.0	82.0
Property, plant and equipment	(109.0)	(121.0)
Timber and timberlands	9.0	10.0
Installment sale gain deferral	7.0	6.0
Total Deferred Tax Liabilities	(130.0)	(143.0)
Deferred Tax Liabilities, Net	(75.0)	(72.0)
Long-term deferred tax asset	(3.0)	(1.0)
Long-term deferred tax liability	$ (78.0)	$ (73.0)