Adjustment Of Asset Retirement Obligation.

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- Definition

Debt Refinancing Cost

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- Definition

Incremental out of pocket costs.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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- Definition

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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Segment Information - Selected Financial Information by Reportable Segment (Parenthetical) (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended	9 Months Ended
	May 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2020	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 21, 2021
Segment Reporting Information [Line Items]
Adjustment of asset retirement obligation						$ 9.4
Restructuring charges						0.1
Goodwill impairment charge		$ 0.0	$ 0.0			0.0	$ 55.2
Senior Notes \| 3.05% Senior Notes Due October 2051
Segment Reporting Information [Line Items]
Debt Refinancing Cost		$ 0.5				$ 0.5
Stated interest rate		3.05%				3.05%		3.05%
Paper Reporting Unit
Segment Reporting Information [Line Items]
Goodwill impairment charge	$ 55.2			$ 55.2	$ 55.2
Jackson, Alabama Mill \| Corrugated Products Facilities
Segment Reporting Information [Line Items]
Adjustment of asset retirement obligation		$ 4.5
San Lorenzo, California [Member]
Segment Reporting Information [Line Items]
Restructuring charges		$ 2.7
San Lorenzo, California [Member] \| Packaging and Paper
Segment Reporting Information [Line Items]
Restructuring charges			3.3				24.1
COVID-19 \| Packaging and Paper
Segment Reporting Information [Line Items]
Incremental out-of-pocket costs							6.9
Hurricane Laura [Member] \| DeRidder Louisiana Mill [Member]
Segment Reporting Information [Line Items]
Restructuring charges			$ 10.0				$ 10.0