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Business Combination, Number Of Facilities Acquired

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Goodwill Impairment, Restructuring and Other Charges [Abstract]

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Goodwill Impairment, Restructuring and Other Special Charges

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Number Of Converting Facilities

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Number Of Mills

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This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

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Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs.

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Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

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Amount of gain (loss) from the difference between the sale price or salvage price and the book value of an asset that was sold or retired, and gain (loss) from the write down of assets from their carrying value to fair value.

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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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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Nature of Business and Summary of Significant Accounting Policies - Research and Development and Restructuring and Other Special Charges, Net (Details) $ in Millions											3 Months Ended								12 Months Ended
	Sep. 30, 2018 facility	Aug. 31, 2018 USD ($)	Jun. 12, 2018 facility	Jan. 01, 2018 facility mill Facilities	Dec. 01, 2017 facility	Oct. 04, 2017 facility	Jul. 10, 2017 facility	Apr. 29, 2016 facility	Feb. 16, 2016 facility	Jan. 05, 2016 facility	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Research and development expense \| $																			$ 8.7	$ 14.4	$ 14.9
Segment Reporting Information [Line Items]
Number of converting facilities \| Facilities				3
Restructuring and Other Special Charges, Net
Charges Associated with Business Combinations \| $																			46.8	16.2	21.2
Business Combination, Integration Related Costs \| $																			6.7	18.6	15.9
Gain on Sale of Assets \| $																			(38.6)	(3.7)	0.0
Total \| $											$ 7.4	$ (27.4)	$ 8.6	$ 26.3	$ 12.8	$ 3.6	$ 6.1	$ 8.6	$ 14.9	$ 31.1	$ 37.1
Paperboard Mills
Segment Reporting Information [Line Items]
Gain on sale of assets \| $		$ 37.1
Leticia Corporation
Segment Reporting Information [Line Items]
Number of facilities acquired	2
PFP, LLC And PFP Dallas Converting, LLC
Segment Reporting Information [Line Items]
Number of facilities acquired			2
Seydaco Packaging Corp.
Segment Reporting Information [Line Items]
Number of folding carton facilities acquired					3
Norgraft Packaging
Segment Reporting Information [Line Items]
Number of folding carton facilities acquired						2
Carton Craft Corporation
Segment Reporting Information [Line Items]
Number of folding carton facilities acquired							2
Colorpak
Segment Reporting Information [Line Items]
Number of folding carton facilities acquired								3
WG Anderson
Segment Reporting Information [Line Items]
Number of folding carton facilities acquired									2
G-Box
Segment Reporting Information [Line Items]
Number of folding carton facilities acquired										2
UNITED STATES \| Leticia Corporation \| Americas Paperboard Packaging
Segment Reporting Information [Line Items]
Number of facilities acquired	2
UNITED STATES \| PFP, LLC And PFP Dallas Converting, LLC \| Americas Paperboard Packaging
Segment Reporting Information [Line Items]
Number of facilities acquired			2
UNITED STATES \| NACP Combination
Segment Reporting Information [Line Items]
Number of mills \| mill				2
Number of converting facilities				3
UNITED STATES \| NACP Combination \| Americas Paperboard Packaging
Segment Reporting Information [Line Items]
Number of mills				2
Number of converting facilities				3
UNITED KINGDOM \| NACP Combination
Segment Reporting Information [Line Items]
Number of converting facilities				1
UNITED KINGDOM \| NACP Combination \| Americas Paperboard Packaging
Segment Reporting Information [Line Items]
Number of converting facilities				1