Summary of Significant Accounting Policies - Changes in accumulated other comprehensive income (loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 01, 2022	Jan. 02, 2021	Dec. 28, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	$ (359,084)	$ (488,428)	$ (350,933)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(96,839)	155,252
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	32,505	17,757
Other Comprehensive Income (Loss), Net of Tax	129,344	(137,495)	(74,457)
Unrecognized pension benefit costs, Tax	(39,470)	89,059
Unrealized loss on interest rate swap, tax	(4,501)	(13,120)
Accumulated Other Comprehensive Income (Loss), Unrealized Gain (Loss) Certain Investments, tax	400
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax	49,600
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Tax	8,619	(7,147)	(8,516)
Other Comprehensive Income (Loss), Unrealized Gain (loss) Certain Investments, Tax	400
Accumulated Foreign Currency Adjustment Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(97,654)	(49,961)	(105,705)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	47,693	(55,744)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Other Comprehensive Income (Loss), Net of Tax	(47,693)	55,744
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(249,696)	(400,919)	(228,336)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	137,187	(174,826)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	14,036	2,243
Other Comprehensive Income (Loss), Net of Tax	151,223	(172,583)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent | Interest Rate Swap
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(13,064)	(37,548)	(16,892)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(6,015)	36,170
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	18,469	15,514
Other Comprehensive Income (Loss), Net of Tax	24,484	(20,656)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	1,330	0	$ 0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(1,330)	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0
Other Comprehensive Income (Loss), Net of Tax	$ 1,330	$ 0