Restructuring and asset impairment - Total Restructuring and Asset Impairment Charges Net (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 29, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jul. 01, 2018	Apr. 01, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring and restructuring-related asset impairment charges									$ 44,819	$ 40,071	$ 19,834
Other asset impairments									15,061	0	18,585
Restructuring/Asset impairment charges	$ 29,238	$ 6,615	$ 13,355	$ 10,672	$ 11,380	$ 22,061	$ 3,567	$ 3,063	59,880	40,071	38,419
Corporate
Restructuring Cost and Reserve [Line Items]
Restructuring and restructuring-related asset impairment charges									2,064	233	463
Consumer Packaging | Operating segments
Restructuring Cost and Reserve [Line Items]
Restructuring and restructuring-related asset impairment charges									34,850	15,205	6,751
Display and Packaging | Operating segments
Restructuring Cost and Reserve [Line Items]
Restructuring and restructuring-related asset impairment charges									2,459	18,800	2,048
Paper and Industrial Converted Products | Operating segments
Restructuring Cost and Reserve [Line Items]
Restructuring and restructuring-related asset impairment charges									4,927	4,301	7,410
Protective Solutions | Operating segments
Restructuring Cost and Reserve [Line Items]
Restructuring and restructuring-related asset impairment charges									519	1,532	3,162
Severance and Termination Benefits
Restructuring Cost and Reserve [Line Items]
Restructuring and restructuring-related asset impairment charges									24,864	15,224	12,684
Asset Impairment/Disposal of Assets
Restructuring Cost and Reserve [Line Items]
Restructuring and restructuring-related asset impairment charges									9,674	6,193	120
Other Costs
Restructuring Cost and Reserve [Line Items]
Restructuring and restructuring-related asset impairment charges									$ 10,281	$ 18,654	$ 7,030