Segment and Geographical Information - Reconciliation of Segment Gross Profit to Condensed Consolidated GAAP Gross Profit (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]
Gross profit	$ 59,650	$ 37,140	$ 170,555	$ 91,976
Construction revenue on solar services contracts	323,636	274,806	938,961	783,019
Stock-based compensation expense			19,776	18,788
Gain (loss) on business divestitures, net	0	0	224	10,458
Operating Segments
Segment Reporting Information [Line Items]
Gross profit	60,702	36,731	180,779	90,128
Intersegment elimination
Segment Reporting Information [Line Items]
Gross profit	(83)	1,752	785	11,604
Construction revenue on solar services contracts	0	(7,294)	11	(32,816)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Legacy utility and power plant projects	0	0	0	207
Construction revenue on solar services contracts	0	0	0	(5,392)
Results of operations of legacy business to be exited	0	0	625	0
Segment Reconciling Items | Gross Profit
Segment Reporting Information [Line Items]
Legacy utility and power plant projects	0	0	0	34
Legacy sale-leaseback transactions	0	0	0	(20)
Gain (loss) on sale and impairment of residential lease assets	249	469	1,262	1,375
Construction revenue on solar services contracts	0	0	0	(4,735)
Stock-based compensation expense	(1,055)	(623)	(3,011)	(1,653)
Amortization of intangible assets	0	(1,189)	0	(4,757)
Gain (loss) on business divestitures, net	(81)	0	(81)	0
Results of operations of legacy business to be exited	$ (82)	$ 0	$ (9,179)	$ 0