Goodwill and Intangible Assets - Details (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill	$ 35.1
Net proceeds from divested assets		$ 70.9
Total, write off due to Ladysmith sale		14.9
Intangible Assets, Net (Excluding Goodwill)	0.0
Goodwill and intangible assets, net	52.0	59.2	$ 276.7
Goodwill, Impairment Loss	0.0	(195.1)	0.0
Amortization of Intangible Assets	(7.2)	(7.5)
Finite-Lived Intangible Assets, Accumulated Amortization	$ 46.9	39.7	37.8
Minimum [Member]
Goodwill [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years
Maximum [Member]
Goodwill [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Consumer Products [Member]
Goodwill [Line Items]
Goodwill	$ 0.0	0.0	209.1
Intangible Assets, Net (Excluding Goodwill)	0.3	4.6	10.1
Goodwill, Impairment Loss		(195.1)
Impairment of Intangible Assets, Finite-lived		0.0
Goodwill, Written off Related to Sale of Business Unit		(14.0)
Intangibles, write off due to Ladysmith sale		0.9
Amortization of Intangible Assets	(4.3)	(4.6)
Pulp And Paperboard [Member]
Goodwill [Line Items]
Goodwill	35.1	35.1	35.1
Intangible Assets, Net (Excluding Goodwill)	16.6	19.5	$ 22.4
Goodwill, Impairment Loss		0.0
Impairment of Intangible Assets, Finite-lived		0.0
Goodwill, Written off Related to Sale of Business Unit		0.0
Intangibles, write off due to Ladysmith sale		0.0
Amortization of Intangible Assets	(2.9)	(2.9)
Customer Relationships [Member]
Goodwill [Line Items]
Intangible Assets, Net (Excluding Goodwill)	15.0	21.0
Trademarks and Trade Names [Member]
Goodwill [Line Items]
Intangible Assets, Net (Excluding Goodwill)	1.7	2.8
Other Intangible Assets [Member]
Goodwill [Line Items]
Intangible Assets, Net (Excluding Goodwill)	$ 0.2	$ 0.3