Segment and Geographical Information - Reconciliation of Segment Revenue to Condensed Consolidated GAAP Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 03, 2021	Sep. 27, 2020	Oct. 03, 2021	Sep. 27, 2020
Segment Reporting Information [Line Items]
Revenue	$ 323,636	$ 274,806	$ 938,961	$ 783,019
Operating Segments
Segment Reporting Information [Line Items]
Total segment revenues as reviewed by CODM	323,636	282,100	938,325	821,020
Intersegment elimination
Segment Reporting Information [Line Items]
Revenue	0	(7,294)	11	(32,816)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Revenue	0	0	0	(5,392)
Legacy utility and power plant projects	0	0	0	207
Results of operations of legacy business to be exited	$ 0	$ 0	$ 625	$ 0