Segment and Geographical Information - Reconciliation of Other Significant Reconciling Items from Segments to Consolidated (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 04, 2021	Mar. 29, 2020
Segment Reporting Information [Line Items]
Gross profit	$ 49,874	$ 29,184
Adjusted EBITDA	(54,722)	21,046
Residential, Light Commercial
Segment Reporting Information [Line Items]
Revenue from Contract with Customers, Reviewed by CODM	237,937	232,140
Gross profit	52,921	33,505
Adjusted EBITDA	25,053	9,236
Residential, Light Commercial
Segment Reporting Information [Line Items]
Revenue from Contract with Customers, Reviewed by CODM	66,263	50,611
Gross profit	4,211	(1,295)
Adjusted EBITDA	576	(7,874)
Others
Segment Reporting Information [Line Items]
Revenue from Contract with Customers, Reviewed by CODM	1,566	32,859
Gross profit	(248)	(9,455)
Adjusted EBITDA	(614)	(8,909)
Operating Segments
Segment Reporting Information [Line Items]
Gross profit	56,884	22,755
Adjusted EBITDA	25,015	(7,547)
Intersegment revenue
Segment Reporting Information [Line Items]
Gross profit	449	13,044
Intersegment revenue | Residential, Light Commercial
Segment Reporting Information [Line Items]
Revenue from Contract with Customers, Reviewed by CODM	0	0
Intersegment revenue | Residential, Light Commercial
Segment Reporting Information [Line Items]
Revenue from Contract with Customers, Reviewed by CODM	0	0
Intersegment revenue | Others
Segment Reporting Information [Line Items]
Revenue from Contract with Customers, Reviewed by CODM	(11)	19,879
Dev Co | Operating Segments | Residential, Light Commercial
Segment Reporting Information [Line Items]
Revenue from Contract with Customers, Reviewed by CODM	231,422	226,630
Dev Co | Operating Segments | Residential, Light Commercial
Segment Reporting Information [Line Items]
Revenue from Contract with Customers, Reviewed by CODM	58,121	46,748
Dev Co | Operating Segments | Others
Segment Reporting Information [Line Items]
Revenue from Contract with Customers, Reviewed by CODM	966	470
Power Co | Operating Segments | Residential, Light Commercial
Segment Reporting Information [Line Items]
Revenue from Contract with Customers, Reviewed by CODM	6,515	5,510
Power Co | Operating Segments | Residential, Light Commercial
Segment Reporting Information [Line Items]
Revenue from Contract with Customers, Reviewed by CODM	8,142	3,863
Power Co | Operating Segments | Others
Segment Reporting Information [Line Items]
Revenue from Contract with Customers, Reviewed by CODM	$ 611	$ 12,510