CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME/(LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 25, 2022	Sep. 30, 2023	Sep. 25, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 53,615	$ 36,617	$ 122,510	$ 103,119
Other comprehensive income/(loss), before tax:
Loss on foreign currency translation adjustments	(2,333)	(7,603)	(1,199)	(13,219)
Pension and postretirement benefits obligation	1,550	5,247	4,656	15,371
Net unrealized gain/(loss) on available-for-sale securities	1,886	(1,631)	5,984	(11,458)
Other comprehensive income/(loss), before tax	1,103	(3,987)	9,441	(9,306)
Income tax expense/(benefit)	290	(983)	2,463	(2,467)
Other comprehensive income/(loss), net of tax	813	(3,004)	6,978	(6,839)
Comprehensive income attributable to common stockholders	$ 54,428	$ 33,613	$ 129,488	$ 96,280