Segment Reporting - Segment Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Segment Reporting Information [Line Items]
Net sales	$ 1,312,314	$ 1,353,931	$ 3,861,095	$ 4,065,357
Operating profit	106,744	138,548	340,574	385,204
Restructuring/Asset impairment charges	(24,149)	(6,615)	(59,633)	(30,642)
Consumer Packaging
Segment Reporting Information [Line Items]
Net sales	583,736	581,368	1,786,774	1,773,834
Display and Packaging
Segment Reporting Information [Line Items]
Net sales	137,610	145,016	366,269	417,403
Paper and Industrial Converted Products
Segment Reporting Information [Line Items]
Net sales	459,312	495,829	1,368,734	1,483,194
Protective Solutions
Segment Reporting Information [Line Items]
Net sales	131,656	131,718	339,318	390,926
Operating Segments \| Consumer Packaging
Segment Reporting Information [Line Items]
Net sales	583,736	581,368	1,786,774	1,773,834
Operating profit	67,897	56,744	221,827	181,801
Operating Segments \| Display and Packaging
Segment Reporting Information [Line Items]
Net sales	137,610	145,016	366,269	417,403
Operating profit	10,773	8,913	24,848	21,256
Operating Segments \| Paper and Industrial Converted Products
Segment Reporting Information [Line Items]
Net sales	459,312	495,829	1,368,734	1,483,194
Operating profit	34,366	59,427	118,343	169,043
Operating Segments \| Protective Solutions
Segment Reporting Information [Line Items]
Net sales	131,656	131,718	339,318	390,926
Operating profit	17,505	13,983	35,991	39,262
Intersegment Sales
Segment Reporting Information [Line Items]
Net sales	35,133	36,203	100,087	106,541
Intersegment Sales \| Consumer Packaging
Segment Reporting Information [Line Items]
Net sales	2,779	1,351	7,503	3,394
Intersegment Sales \| Display and Packaging
Segment Reporting Information [Line Items]
Net sales	1,079	1,112	3,546	3,393
Intersegment Sales \| Paper and Industrial Converted Products
Segment Reporting Information [Line Items]
Net sales	30,873	33,485	87,933	98,674
Intersegment Sales \| Protective Solutions
Segment Reporting Information [Line Items]
Net sales	402	255	1,105	1,080
Segment Reconciling Items
Segment Reporting Information [Line Items]
Other, net	$ 352	$ 6,096	$ (802)	$ 4,484

The net result for the period of deducting operating expenses from operating revenues.

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