Segment and Geographical Information - Reconciliation of Segment Gross Profit to Condensed Consolidated GAAP Gross Profit) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 29, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Gross profit	$ 37,448	$ (37,285)
Construction revenue on solar services contracts	449,190	348,225
Loss on sale and impairment of residential lease assets	289	9,226
Stock-based compensation	6,867	5,666
Business reorganization costs	1,576	(665)
Operating Segments
Segment Reporting Information [Line Items]
Gross profit	48,201	17,015
Intersegment Eliminations
Segment Reporting Information [Line Items]
Gross profit	8,763	7,636
Construction revenue on solar services contracts	(88,875)	(60,800)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Legacy utility and power plant projects	207	171
Gross Profit \| Segment Reconciling Items
Segment Reporting Information [Line Items]
Legacy utility and power plant projects	34	(116)
Business process improvements	(2,464)	0
Legacy sale-leaseback transactions	(20)	823
Loss on sale and impairment of residential lease assets	448	125
Cost of above-market polysilicon	(10,043)	(49,428)
Litigation	163	0
Stock-based compensation	(1,109)	(168)
Amortization of intangible assets	(1,785)	(1,786)
Business reorganization costs	(5)	0
Service
Segment Reporting Information [Line Items]
Construction revenue on solar services contracts	(4,735)	3,740
Service \| Segment Reconciling Items
Segment Reporting Information [Line Items]
Construction revenue on solar services contracts	(5,392)	(63,505)
Service \| Gross Profit \| Segment Reconciling Items
Segment Reporting Information [Line Items]
Construction revenue on solar services contracts	$ (4,735)	$ (11,386)

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