Changes in accumulated other comprehensive income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 28, 2024	Sep. 30, 2023	Sep. 28, 2024	Sep. 30, 2023
Accumulated Other Comprehensive Income [Roll Forward]
Beginning of Period			$ (223,198)	$ (278,472)
Other comprehensive income before reclassification			34,816	14,990
Amounts reclassified from accumulated other comprehensive income			(19,774)	(22,376)
Net current-period other comprehensive income			15,042	(7,386)
End of Period	$ (208,156)	$ (285,858)	(208,156)	(285,858)
Accumulated Other Comprehensive (income) Loss, Defined Benefit Plan, Tax	4,800	(1,500)	4,800	(1,500)
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Tax	6,200	16,100	6,200	16,100
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax			800	500
Unrealized gain on interest rate swap, tax	(4,120)	7	(4,976)	(731)
Accumulated Translation Adjustment
Accumulated Other Comprehensive Income [Roll Forward]
Beginning of Period			(145,490)	(205,345)
Other comprehensive income before reclassification			31,352	(4,751)
Amounts reclassified from accumulated other comprehensive income			0	0
Net current-period other comprehensive income			31,352	(4,751)
End of Period	(114,138)	(210,096)	(114,138)	(210,096)
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income [Roll Forward]
Beginning of Period			(109,713)	(121,701)
Other comprehensive income before reclassification			5,671	2,131
Amounts reclassified from accumulated other comprehensive income			1,535	1,587
Net current-period other comprehensive income			(4,136)	(544)
End of Period	(113,849)	(122,245)	(113,849)	(122,245)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent | Interest Rate Swap
Accumulated Other Comprehensive Income [Roll Forward]
Beginning of Period			32,005	48,574
Other comprehensive income before reclassification			9,135	21,872
Amounts reclassified from accumulated other comprehensive income			(21,309)	(23,963)
Net current-period other comprehensive income			(12,174)	(2,091)
End of Period	$ 19,831	$ 46,483	$ 19,831	$ 46,483