Business Combinations - Additional Information (Details) $ in Millions			3 Months Ended	9 Months Ended		12 Months Ended
	Apr. 01, 2020 USD ($) facility	Jan. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Business Acquisition [Line Items]
Purchase price of business acquisition				$ 120.6	$ 52.9
Number of converting facilities | facility	7
Quad/Graphics, Inc.
Business Acquisition [Line Items]
Purchase price of business acquisition		$ 41.0
Identifiable tangible assets		42.8
Bargain purchase gain		6.6	$ 6.6
Net sales from acquisition				58.5
Income (loss) from acquisition				(0.6)
Quad/Graphics, Inc. | Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets		$ 4.7
Useful life		15 years
Consumer Packaging Group
Business Acquisition [Line Items]
Purchase price of business acquisition	$ 80.0
Identifiable tangible assets	$ 66.9
Number of converting facilities | facility	7
Net sales from acquisition				116.6
Income (loss) from acquisition				$ 5.1
Consumer Packaging Group | Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets	$ 13.2
Useful life	15 years
Artistic Carton Company
Business Acquisition [Line Items]
Total payments to acquire business						$ 53.0