Assets Held For Sale and Asset Restructuring Costs (Details) - USD ($) $ in Millions		3 Months Ended
	Jun. 28, 2021	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Restructuring Cost and Reserve [Line Items]
Net book value of assets		$ 291.5		$ 295.5
Other restructuring and non-routine costs			$ 0.0
Assets held for sale		10.5		10.5
Liabilities held for sale		0.5		$ 0.5
Reduction of restructuring charges		0.6
Appleton Mill | Disposal Group, Held-for-sale, Not Discontinued Operations
Restructuring Cost and Reserve [Line Items]
Assets held for sale		10.5
Liabilities held for sale		$ 0.5
Facility Closing | Appleton Mill Closure
Restructuring Cost and Reserve [Line Items]
Net book value of assets	$ 43.0
Asset impairment charges	32.4
Impairment loss, after tax	24.3
Other restructuring and non-routine costs	5.0
Elimination of deferred tax benefits due to mill closure	$ 2.9