Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Segment Information - Selected Financial Information by Reportable Segment (Parenthetical) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Wallula, Washington Mill
Segment Reporting Information [Line Items]
High-performance of virgin kraft linerboard machine percentage	100.00%
Paper \| Wallula, Washington Mill
Segment Reporting Information [Line Items]
Restructuring charges	$ 13.6	$ 0.6	$ 22.4
High-performance of virgin kraft linerboard machine percentage	100.00%	100.00%
Packaging And Corporate And Other
Segment Reporting Information [Line Items]
Restructuring charges	$ 0.2		$ 0.5