Segment Information (Details)	9 Months Ended	12 Months Ended
	Oct. 02, 2016 USD ($)	Dec. 31, 2017 USD ($) segments Rate	Jan. 01, 2017 USD ($) Rate	Jan. 03, 2016 USD ($) Rate	Dec. 28, 2014 USD ($)	Dec. 29, 2013 USD ($)	Jul. 22, 2016 USD ($)
Segment Reporting Information [Line Items]
Sales-type Lease, Impairment Loss		$ 624,335,000	$ 0	$ 0
Loss Contingency Accrual		$ 43,900,000
Reconciliation of Operating Profit (Loss) from Segments to Consolidated		338115	468465	785284
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest		$ (1,117,064,000)	$ (564,595,000)	$ (242,311,000)
Number of Reportable Segments | segments		3
Cost of revenue		$ 1,887,084,000	2,369,596,000	1,331,827,000
Gross margin		(15,271,000)	189,966,000	244,646,000
Revenue		1,871,813,000	2,559,562,000	1,576,473,000
Asset Impairment Charges		(473,709,000)
Stock-based compensation expense		34,674,000	61,499,000	58,960,000
Stock-based compensation		34,674,000	61,498,000	58,960,000
Amortization of Intangible Assets		(19,700,000)	(13,000,000)	(5,100,000)
Depreciation, Nonproduction		(2,300,000)
Restructuring Costs		(21,045,000)	(207,190,000)	(6,391,000)
Goodwill, Impairment Loss		0	147,365,000	0	$ 0	$ 0
Goodwill, Impairment Loss	$ (89,600,000)	(147,400,000)
Goodwill, Acquired During Period			89,600,000
Non-cash interest expense		(18,390,000)	(1,057,000)	(6,184,000)
Income (Loss) from Equity Method Investments		(20,211,000)	(28,070,000)	(9,569,000)
Net Income (Loss) Attributable to Noncontrolling Interest		$ (241,747,000)	$ (72,780,000)	$ (112,417,000)
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Reconciliation of Operating Profit (Loss) from Segments to Consolidated		-148462	-156593	-130258
Residential leases [Member]
Segment Reporting Information [Line Items]
Sales-type Lease, Impairment Loss		$ 624,335,000
Reconciliation of Operating Profit (Loss) from Segments to Consolidated		195181	203388	243352
Goodwill, Impairment Loss			$ (49,951,000)
Goodwill, Acquired During Period			$ 17,771,000
Commercial [Member]
Segment Reporting Information [Line Items]
Reconciliation of Operating Profit (Loss) from Segments to Consolidated		72480	65964	56789
Goodwill, Impairment Loss			$ (33,260,000)
Goodwill, Acquired During Period			23,316,000
Existing [Member]
Segment Reporting Information [Line Items]
Goodwill, Impairment Loss		$ 0	$ 57,765,000	$ 0
Power Plant [Member]
Segment Reporting Information [Line Items]
Reconciliation of Operating Profit (Loss) from Segments to Consolidated		70454	199113	485143
Segment Reporting, Disclosure of Major Customers			n/a	n/a
Goodwill, Impairment Loss			$ (64,154,000)
Goodwill, Acquired During Period			$ 48,513,000
Power Plant [Member] | Actis GP LLP [Member]
Segment Reporting Information [Line Items]
Segment Reporting, Disclosure of Major Customers		.13
Power Plant [Member] | 8point3 [Member]
Segment Reporting Information [Line Items]
Segment Reporting, Disclosure of Major Customers		*	0.1	n/a
Power Plant [Member] | Southern Renewable Partnerships [Member]
Segment Reporting Information [Line Items]
Segment Reporting, Disclosure of Major Customers		*	0.15	n/a
Power Plant [Member] | Mid American Energy Holdings Company [Member]
Segment Reporting Information [Line Items]
Segment Reporting, Disclosure of Major Customers		n/a	*	0.14
Power Plant [Member] | NRG Solar Inc. [Member]
Segment Reporting Information [Line Items]
Revenue As Percentage Of Total Revenues			0.00%	0.00%
Revenue [Member] | Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization		$ (164,970,000)	$ (156,464,000)	$ (133,456,000)
8point3 Energy Partners		(11,924,000)	(54,379,000)	(408,780,000)
Profit, Operating Lease		0	1,889,000	(2,000,000)
Other Revenue, Net		$ 0	$ 31,000	$ (162,000)
Loss Contingency, Actions Taken by Court, Arbitrator or Mediator		0	5852	6459
Stock-based compensation		$ (34,674,000)	$ (61,498,000)	$ (58,960,000)
Amortization of Intangible Assets		19,048,000	17,369,000	4,717,000
Restructuring Costs		(21,045,000)	(207,189,000)	(6,056,000)
Net Income (Loss) Attributable to Noncontrolling Interest		82,000	304,000	(28,033,000)
Non-cash interest expense		(128,000)	(1,057,000)	(6,519,000)
CostofAboveMarketPolysilicon		(166,906,000)	(148,265,000)	(98,500,000)
Income (Loss) from Equity Method Investments		(20,211,000)	(28,069,000)	(9,569,000)
Net Income (Loss) Attributable to Noncontrolling Interest		(241,747,000)	(72,780,000)	(112,417,000)
Cash Interest Expense, Net of Interest Income		(79,965,000)	(57,734,000)	(37,643,000)
Gross margin [Member] | Residential leases [Member]
Segment Reporting Information [Line Items]
Gross margin		$ 78,025,000	$ 116,772,000	$ 135,071,000
Gross margin, As a percentage of total revenues | Rate		12.50%	16.20%	21.00%
Gross margin, As reviewed by CODM		$ 113,804,000	$ 161,795,000	$ 170,961,000
Gross margin, As a percentage of total revenues (As reviewed by CODM) | Rate		18.50%	22.80%	26.40%
Gross margin [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Gross margin		$ (21,163,000)	$ (1,796,000)	$ 17,543,000
Gross margin, As a percentage of total revenues | Rate		(4.60%)	(0.40%)	6.30%
Gross margin, As reviewed by CODM		$ 69,542,000	$ 57,744,000	$ 71,421,000
Gross margin, As a percentage of total revenues (As reviewed by CODM) | Rate		9.70%	11.10%	18.20%
Gross margin [Member] | Power Plant [Member]
Segment Reporting Information [Line Items]
Gross margin		$ (72,133,000)	$ 74,990,000	$ 92,032,000
Gross margin, As a percentage of total revenues | Rate		(9.20%)	5.30%	14.00%
Gross margin, As reviewed by CODM		$ 52,455,000	$ 172,247,000	$ 481,119,000
Gross margin, As a percentage of total revenues (As reviewed by CODM) | Rate		6.60%	11.70%	30.60%
8point3 Energy Partners		$ (381,000)	$ (8,418,000)	$ (338,371,000)
Gross margin [Member] | Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Gross margin, Utility and power plant projects		(31,390,000)	(10,274,000)	3,016,000
Sale-leaseback trasaction		(38,782,000)	(11,700,000)	0
Gross margin [Member] | Segment Reconciling Items [Member] | Residential leases [Member]
Segment Reporting Information [Line Items]
8point3 Energy Partners		1,927,000	1,657,000	1,148,000
Gross margin, Utility and power plant projects		0	0	0
Profit, Operating Lease			1,942,000	(2,000,000)
Sale-leaseback trasaction		0	0
Stock-based compensation expense		(1,875,000)	$ (5,464,000)	$ (4,764,000)
Loss Contingency, Actions Taken by Court, Arbitrator or Mediator			1345	2084
Amortization of Intangible Assets		3,783,000	$ 2,965,000	$ 728,000
Non-cash interest expense		8,000	227,000	638,000
CostofAboveMarketPolysilicon		(31,507,000)	(41,311,000)	(30,951,000)
Gross margin, Other				41,000
Gross margin [Member] | Segment Reconciling Items [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
8point3 Energy Partners		(2,796,000)	(3,751,000)	(32,734,000)
Gross margin, Utility and power plant projects		(811,000)	0	0
Profit, Operating Lease			0	0
Sale-leaseback trasaction		(31,767,000)	(11,351,000)
Stock-based compensation expense		(2,102,000)	$ (4,234,000)	$ (2,676,000)
Loss Contingency, Actions Taken by Court, Arbitrator or Mediator			922	1697
Amortization of Intangible Assets		3,202,000	$ 3,059,000	$ 451,000
Non-cash interest expense		9,000	199,000	330,000
CostofAboveMarketPolysilicon		(49,184,000)	(37,868,000)	(19,351,000)
Gross margin, Other				33,000
Gross margin [Member] | Segment Reconciling Items [Member] | Power Plant [Member]
Segment Reporting Information [Line Items]
Gross margin, Utility and power plant projects		(30,579,000)	(10,274,000)	3,016,000
Profit, Operating Lease			0	0
Sale-leaseback trasaction		673,000	0
Stock-based compensation expense		(3,917,000)	$ (10,879,000)	$ (5,903,000)
Loss Contingency, Actions Taken by Court, Arbitrator or Mediator			3585	2678
Amortization of Intangible Assets		3,221,000	$ 1,655,000	$ 1,155,000
Non-cash interest expense		15,000	530,000	1,069,000
CostofAboveMarketPolysilicon		(86,215,000)	(69,086,000)	(48,198,000)
Gross margin, Other				85,000
Sales [Member] | Residential leases [Member]
Segment Reporting Information [Line Items]
Revenue		622,066,000	720,331,000	643,520,000
Revenue, As reviewed by CODM		616,735,000	708,687,000	647,213,000
Sales [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
Revenue		461,932,000	436,915,000	277,143,000
Revenue, As reviewed by CODM		715,735,000	520,818,000	392,866,000
Sales [Member] | Power Plant [Member]
Segment Reporting Information [Line Items]
Revenue		787,815,000	1,402,316,000	655,810,000
Revenue, As reviewed by CODM		796,088,000	1,473,355,000	1,572,571,000
Sales [Member] | Segment Reconciling Items [Member] | Residential leases [Member]
Segment Reporting Information [Line Items]
8point3 Energy Partners		5,331,000	5,248,000	2,754,000
Revenue, Utility and power plant project		0	0	0
revenue, net, operating lease			6,396,000	(6,447,000)
Sale-leaseback trasaction		0	0
Stock-based compensation expense		0	$ 0	$ 0
Loss Contingency, Actions Taken by Court, Arbitrator or Mediator			0	0
Amortization of Intangible Assets		0
Non-cash interest expense		0	$ 0	$ 0
CostofAboveMarketPolysilicon		0	0	0
Sales [Member] | Segment Reconciling Items [Member] | Commercial [Member]
Segment Reporting Information [Line Items]
8point3 Energy Partners		(4,471,000)	(5,370,000)	(115,723,000)
Revenue, Utility and power plant project		(7,115,000)	0	0
revenue, net, operating lease			0	0
Sale-leaseback trasaction		(242,217,000)	(78,533,000)
Stock-based compensation expense		0	$ 0	$ 0
Loss Contingency, Actions Taken by Court, Arbitrator or Mediator			0	0
Amortization of Intangible Assets		0	$ 0	$ 0
Non-cash interest expense		0	0	0
CostofAboveMarketPolysilicon		0	0	0
Sales [Member] | Segment Reconciling Items [Member] | Power Plant [Member]
Segment Reporting Information [Line Items]
8point3 Energy Partners		797,000	(61,596,000)	(898,765,000)
Revenue, Utility and power plant project		21,367,000	(9,443,000)	(17,996,000)
revenue, net, operating lease			0	0
Sale-leaseback trasaction		(30,437,000)	0
Stock-based compensation expense		0	$ 0	$ 0
Loss Contingency, Actions Taken by Court, Arbitrator or Mediator			0	0
Amortization of Intangible Assets		0	$ 0	$ 0
Non-cash interest expense		0	0	0
CostofAboveMarketPolysilicon		$ 0	$ 0	$ 0
JAPAN
Segment Reporting Information [Line Items]
Revenue As Percentage Of Total Revenues		6.00%	6.00%	12.00%
REST OF WORLD [Member]
Segment Reporting Information [Line Items]
Revenue As Percentage Of Total Revenues		14.00%	9.00%	19.00%
All Countries [Domain]
Segment Reporting Information [Line Items]
Revenue As Percentage Of Total Revenues		100.00%	100.00%	100.00%
UNITED STATES
Segment Reporting Information [Line Items]
Revenue As Percentage Of Total Revenues		80.00%	85.00%	69.00%
August 2016 Plan [Member]
Segment Reporting Information [Line Items]
Restructuring Costs		$ (749,000)	$ (34,438,000)	$ 0
First Philec Arbitration [Member]
Segment Reporting Information [Line Items]
Loss Contingency Accrual							$ 50,500,000