Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 26, 2021	Jun. 27, 2020	Jun. 26, 2021	Jun. 27, 2020
Net income (loss)	$ 95,096	$ (4,740)	$ 122,703	$ (22,016)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	2,890	1,897	(7,356)	968
Adjustments related to postretirement benefits	151	0	(29)	0
Change in unrealized gain/loss on investments	(8)	0	(14)	0
Reclassifications due to sale of PTG Test business	(2,515)	0	(2,515)	0
Other comprehensive income (loss), net of tax	518	1,897	(9,914)	968
Comprehensive income (loss)	$ 95,614	$ (2,843)	$ 112,789	$ (21,048)