Financial instruments - Foreign exchange gains and losses recognized within AOCI and the interest benefit recognized within interest expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2022	Mar. 28, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Foreign exchange gains	$ (23,329)	$ (24,075)
Interest benefit	4,848	4,647
Cross-currency interest rate swaps | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Interest benefit	4,848	4,647
Cross-currency interest rate swaps | Cash flow hedging
Derivative Instruments, Gain (Loss) [Line Items]
Foreign exchange gains	$ 3,840	$ 17,614