Segment Reporting - Reconciliation of Other Segment to Consolidated Totals (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 29, 2025	Jun. 30, 2024	Jun. 29, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Equity in earnings of affiliates, net of tax	$ 2,270	$ 2,274	$ 4,191	$ 3,411
Continuing Operations
Segment Reporting Information [Line Items]
Equity in earnings of affiliates, net of tax	2,270	2,274	4,191	3,411
Depreciation and amortization	129,475	74,069	251,278	149,015
Operating Segments
Segment Reporting Information [Line Items]
Equity in earnings of affiliates, net of tax	2,270	2,274	4,191	3,411
Depreciation and amortization	82,639	53,873	159,927	107,273
Operating Segments \| Consumer Packaging
Segment Reporting Information [Line Items]
Equity in earnings of affiliates, net of tax	170	35	119	47
Depreciation and amortization	52,801	25,232	101,756	50,129
Operating Segments \| Industrial Paper Packaging
Segment Reporting Information [Line Items]
Equity in earnings of affiliates, net of tax	2,100	2,239	4,072	3,364
Depreciation and amortization	29,838	28,641	58,171	57,144
All Other
Segment Reporting Information [Line Items]
Equity in earnings of affiliates, net of tax	0	0	0	0
Depreciation and amortization	$ 46,836	$ 20,196	$ 91,351	$ 41,742