Changes in accumulated other comprehensive income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2022	Jul. 03, 2021	Jul. 02, 2022	Jul. 03, 2021
Accumulated Other Comprehensive Income [Roll Forward]
Beginning of Period			$ (359,084)	$ (488,428)
Other comprehensive income before reclassification			(63,106)	(11,052)
Amounts reclassified from accumulated other comprehensive income			7,817	10,230
Net current-period other comprehensive income			(55,289)	(822)
End of Period	$ (414,373)	$ (489,250)	(414,373)	(489,250)
Accumulated Other Comprehensive (income) Loss, Defined Benefit Plan, Tax	(35,400)	(89,700)	(35,400)	(89,700)
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Tax	9,300	(8,500)	9,300	(8,500)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax			4,100	(600)
Unrealized gain on interest rate swap, tax	2,923	245	13,815	4,572
Other Comprehensive Income (Loss), Unrealized Gain (loss) Certain Investments, Tax			(400)
Accumulated Translation Adjustment
Accumulated Other Comprehensive Income [Roll Forward]
Beginning of Period			(97,654)	(49,961)
Other comprehensive income before reclassification			(119,402)	(11,119)
Amounts reclassified from accumulated other comprehensive income			0	0
Net current-period other comprehensive income			(119,402)	(11,119)
End of Period	(217,056)	(61,080)	(217,056)	(61,080)
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income [Roll Forward]
Beginning of Period			(249,696)	(400,919)
Other comprehensive income before reclassification			(26,199)	2,818
Amounts reclassified from accumulated other comprehensive income			0	0
Net current-period other comprehensive income			26,199	(2,818)
End of Period	(223,497)	(403,737)	(223,497)	(403,737)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent | Interest Rate Swap
Accumulated Other Comprehensive Income [Roll Forward]
Beginning of Period			(13,064)	(37,548)
Other comprehensive income before reclassification			31,427	2,885
Amounts reclassified from accumulated other comprehensive income			7,817	10,230
Net current-period other comprehensive income			39,244	13,115
End of Period	26,180	(24,433)	26,180	(24,433)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent
Accumulated Other Comprehensive Income [Roll Forward]
Beginning of Period			1,330	0
Other comprehensive income before reclassification			(1,330)	0
Amounts reclassified from accumulated other comprehensive income			0	0
Net current-period other comprehensive income			(1,330)	0
End of Period	$ 0	$ 0	$ 0	$ 0