Shareholders' equity - Change in accumulated other comprehensive income, net of tax (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 26, 2022	Jun. 27, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	$ 3,754,748	$ 3,336,457
Other comprehensive income (loss) before reclassifications	(64,604)	(18,560)
Amounts reclassified from accumulated other comprehensive income	2,868	3,898
Net current-period other comprehensive income (loss)	(61,736)	(14,662)
Ending balance	3,852,730	3,466,102
Accumulated Other Comprehensive (Loss) Income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(346,959)	(297,298)
Ending balance	(408,695)	(311,960)
Cash Flow Hedges
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	1,081	(482)
Other comprehensive income (loss) before reclassifications	2,839	(574)
Amounts reclassified from accumulated other comprehensive income	195	998
Net current-period other comprehensive income (loss)	3,034	424
Ending balance	4,115	(58)
Pension and Other Postretirement Benefit Plans
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(138,290)	(150,257)
Other comprehensive income (loss) before reclassifications	939	9
Amounts reclassified from accumulated other comprehensive income	2,673	2,900
Net current-period other comprehensive income (loss)	3,612	2,909
Ending balance	(134,678)	(147,348)
Foreign Currency Translation Adjustment
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(209,750)	(146,559)
Other comprehensive income (loss) before reclassifications	(68,382)	(17,995)
Amounts reclassified from accumulated other comprehensive income	0	0
Net current-period other comprehensive income (loss)	(68,382)	(17,995)
Ending balance	$ (278,132)	$ (164,554)