Exit Activities (Details) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2019 USD ($)	Dec. 31, 2022 USD ($) mill	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Exit Activities			$ 10.2	$ 0.0	$ 0.0
Facility Closing
Restructuring Cost and Reserve [Line Items]
Exit Activities	$ 14.9
Forecast | Facility Closing
Restructuring Cost and Reserve [Line Items]
Number of mills expected to close | mill		2
Forecast | Facility Closing | Minimum
Restructuring Cost and Reserve [Line Items]
Accelerated depreciation		$ 50.0
Forecast | Facility Closing | Maximum
Restructuring Cost and Reserve [Line Items]
Accelerated depreciation		60.0
Forecast | One-time Termination Benefits | Minimum
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges		15.0
Forecast | One-time Termination Benefits | Maximum
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges		20.0
Forecast | Construction-in-Progress
Restructuring Cost and Reserve [Line Items]
Investment in new CRB mill		$ 600.0