Segment and Geographical Information - Reconciliation of Segment Revenue to Condensed Consolidated GAAP Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 29, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Revenue	$ 449,190	$ 348,225
Operating Segments
Segment Reporting Information [Line Items]
Total segment revenue as reviewed by CODM	543,250	472,359
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenue	(88,875)	(60,800)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Legacy utility and power plant projects	207	171
Service
Segment Reporting Information [Line Items]
Revenue	(4,735)	3,740
Service \| Segment Reconciling Items
Segment Reporting Information [Line Items]
Revenue	$ (5,392)	$ (63,505)

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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration