Segment and Geographical Information - Reconciliation of Segment Revenue to Condensed Consolidated GAAP Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
Apr. 04, 2021	Mar. 29, 2020
Segment Reporting Information [Line Items]
Revenue	$ 306,398	$ 290,546
Operating Segments
Segment Reporting Information [Line Items]
Total segment revenue as reviewed by CODM	305,766	315,610
Intersegment revenue
Segment Reporting Information [Line Items]
Revenue	11	(19,879)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Revenue	0	(5,392)
Legacy utility and power plant projects	0	207
Results of operations of legacy business to be exited	$ 621	$ 0

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details