Inventories - Inventories (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Inventory [Line Items]
Logs, pulpwood, chips and sawdust	$ 14.0		$ 14.0		$ 17.2
Inventory Pulp	18.2		18.2		11.5
Pulp, paperboard and tissue products	155.1		155.1		137.0
Materials and supplies	95.6		95.6		97.7
Inventories	282.9		282.9		$ 263.3
Pension Plan [Member]
Inventory [Line Items]
Defined Benefit Plan, Amortization of Gain (Loss)	$ 2.6	$ 2.5	$ 5.1	$ 5.0

Inventory Pulp

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- Definition

Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan.

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- Definition

Amount before valuation and LIFO reserves of completed merchandise or goods expected to be sold within one year or operating cycle, if longer.

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- Definition

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.

+ References

No definition available.

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- Definition

Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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- Definition

Amount before valuation and LIFO reserves of raw materials expected to be sold, or consumed within one year or operating cycle, if longer.

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- Definition

Amount before valuation and LIFO reserves of other supplies used within the manufacturing or production process expected to be consumed within one year or operating cycle, if longer.

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