Goodwill and Intangible Assets -Goodwill - Additional Information (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	[1],[2]
Goodwill [Line Items]
Goodwill	$ 918.7	$ 917.3	$ 883.2
Packaging
Goodwill [Line Items]
Goodwill	863.5	862.1	828.0
Paper
Goodwill [Line Items]
Goodwill	$ 55.2	$ 55.2	$ 55.2

[1] During 2018, the Company recorded a $5.5 million adjustment to increase the goodwill balance for the Company’s October 2017 acquisition of Sacramento Container

[2] In connection with the October 2018 acquisition of Englander, the Company recorded $28.6 million of goodwill in the Packaging segment in 2018.