Goodwill and Intangible Assets - Details (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Line Items]
Intangible Assets, Net (Including Goodwill)	$ 41.5	$ 43.6	$ 45.9
Amortization of Intangible Assets	(2.1)	(2.2)
Finite-Lived Intangible Assets, Accumulated Amortization	28.4	26.3
Intangible Assets, Gross (Excluding Goodwill)	$ 34.9	34.9
Maximum [Member]
Goodwill [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Pulp And Paperboard [Member]
Goodwill [Line Items]
Goodwill	$ 35.1	35.1	35.1
Intangible Assets, Net (Excluding Goodwill)	6.4	8.6	$ 10.8
Amortization of Intangible Assets	(2.1)	(2.2)
Customer Relationships [Member]
Goodwill [Line Items]
Intangible Assets, Net (Excluding Goodwill)	$ 6.4	$ 8.6