Goodwill and Intangible Assets - Intangible Assets (Parenthetical) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Oct. 31, 2017	Oct. 02, 2017	Dec. 31, 2016	Nov. 30, 2016	Aug. 31, 2016
Sacramento Container Corporation
Finite Lived Intangible Assets [Line Items]
Other intangible assets	$ 72.6		$ 72.6
Sacramento Container Corporation | Customer Relationships
Finite Lived Intangible Assets [Line Items]
Other intangible assets		$ 68.4
Sacramento Container Corporation | Trademarks and Trade Names
Finite Lived Intangible Assets [Line Items]
Other intangible assets		4.1
Sacramento Container Corporation | Other Intangible Assets
Finite Lived Intangible Assets [Line Items]
Other intangible assets		$ 0.1
TimBar Corporation
Finite Lived Intangible Assets [Line Items]
Other intangible assets	94.4			$ 94.4
TimBar Corporation | Customer Relationships
Finite Lived Intangible Assets [Line Items]
Other intangible assets						$ 88.0
TimBar Corporation | Trademarks and Trade Names
Finite Lived Intangible Assets [Line Items]
Other intangible assets						4.9
TimBar Corporation | Other Intangible Assets
Finite Lived Intangible Assets [Line Items]
Other intangible assets						$ 1.5
Columbus Container Inc
Finite Lived Intangible Assets [Line Items]
Other intangible assets	$ 32.3			$ 26.3
Columbus Container Inc | Customer Relationships
Finite Lived Intangible Assets [Line Items]
Other intangible assets					$ 30.0
Columbus Container Inc | Trademarks and Trade Names
Finite Lived Intangible Assets [Line Items]
Other intangible assets					2.2
Columbus Container Inc | Other Intangible Assets
Finite Lived Intangible Assets [Line Items]
Other intangible assets					$ 0.2