CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (8,991)	$ 43,792	$ 15,653	$ 80,781
Other comprehensive (loss) income:
Pension and postemployment adjustment, net of tax	(10,839)	161	(10,278)	112
Foreign currency translation adjustments	8,422	(5,892)	(7,118)	2,230
Comprehensive (loss) income	$ (11,408)	$ 38,061	$ (1,743)	$ 83,123