Discontinued Operations, Divestitures and Acquisitions - Divestitures (Details) - Polystyrene Food Tray Business - Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations R$ in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)	Aug. 01, 2017 BRL (R$)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross purchase price	$ 8.2	R$ 26.9
Gain on sale	$ 1.0