Segment Reporting - Reconciliation of Other Segment to Consolidated Totals (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 28, 2025	Sep. 29, 2024	Sep. 28, 2025	Sep. 29, 2024
Segment Reporting Information [Line Items]
Equity in earnings of affiliates, net of tax	$ 3,020	$ 2,807	$ 7,211	$ 6,218
Continuing Operations
Segment Reporting Information [Line Items]
Equity in earnings of affiliates, net of tax	3,020	2,807	7,211	6,218
Depreciation and amortization	131,656	74,918	382,934	223,933
Operating Segments
Segment Reporting Information [Line Items]
Equity in earnings of affiliates, net of tax	3,020	2,807	7,211	6,218
Depreciation and amortization	80,374	54,565	240,301	161,838
Operating Segments \| Consumer Packaging
Segment Reporting Information [Line Items]
Equity in earnings of affiliates, net of tax	190	369	309	416
Depreciation and amortization	50,419	25,576	152,175	75,705
Operating Segments \| Industrial Paper Packaging
Segment Reporting Information [Line Items]
Equity in earnings of affiliates, net of tax	2,830	2,438	6,902	5,802
Depreciation and amortization	29,955	28,989	88,126	86,133
All Other
Segment Reporting Information [Line Items]
Equity in earnings of affiliates, net of tax	0	0	0	0
Depreciation and amortization	$ 51,282	$ 20,353	$ 142,633	$ 62,095