Fair Value - Estimated Fair Values and Carrying Values for Customer Receivables and Debt Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Aug. 31, 2020	May 01, 2020	Mar. 31, 2020	Mar. 30, 2020	Dec. 31, 2019	Dec. 31, 2018
Term loan | Net Carrying Value | Term Loan due November 2020, Recourse
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	$ 0					$ 1,536
Term loan | Net Carrying Value | Term Loan due September 2028, Non-Recourse
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	31,746					34,969
Term loan | Net Carrying Value | Term Loan due December 2021, Non-Recourse
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	114,138					120,437
Term loan | Fair Value | Term Loan due November 2020, Recourse
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	0					1,590
Term loan | Fair Value | Term Loan due September 2028, Non-Recourse
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	37,658					41,108
Term loan | Fair Value | Term Loan due December 2021, Non-Recourse
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	116,113					120,510
Convertible promissory notes | Net Carrying Value | Convertible Promissory Notes Interest Rate 5% Due December 2020, Recourse
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	0					36,482
Convertible promissory notes | Net Carrying Value | 10% Convertible Promissory Notes due December 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	0					273,410
Convertible promissory notes | Fair Value | Convertible Promissory Notes Interest Rate 5% Due December 2020, Recourse
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	0					32,070
Convertible promissory notes | Fair Value | 10% Convertible Promissory Notes due December 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	0					302,047
Notes | Net Carrying Value | 10% Senior Secured notes due July 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	0					89,962
Notes | Net Carrying Value | 10.25% Senior Secured Notes due March 2027
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	68,614					0
Notes | Fair Value | 10% Senior Secured notes due July 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	0					97,512
Notes | Fair Value | 10.25% Senior Secured Notes due March 2027
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	71,831					0
Senior secured notes | Net Carrying Value | 2.5% Green Convertible Senior Notes due August 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	99,394					0
Senior secured notes | Net Carrying Value | Senior Secured Notes due March 2030, Non-Recourse
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	77,007					80,016
Senior secured notes | Fair Value | 2.5% Green Convertible Senior Notes due August 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	426,229					0
Senior secured notes | Fair Value | Senior Secured Notes due March 2030, Non-Recourse
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument						87,618
Customer financing receivables | Net Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Customer financing receivables	50,746					55,855
Customer financing receivables | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Customer financing receivables	$ 42,679					$ 44,002
Term Loan due November 2020, Recourse | Term loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate percentage	4.00%					4.00%
Convertible Promissory Notes Interest Rate 5% Due December 2020, Recourse | Convertible promissory notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate percentage	5.00%				5.00%	5.00%
10% Convertible Promissory Notes due December 2021 | Convertible promissory notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate percentage	10.00%			10.00%		10.00%	10.00%
10% Senior Secured notes due July 2024 | Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate percentage	10.00%					10.00%
10.25% Senior Secured Notes due March 2027
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate percentage			10.25%
10.25% Senior Secured Notes due March 2027 | Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate percentage	10.25%					10.25%
2.5% Green Convertible Senior Notes due August 2025 | Senior secured notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate percentage	2.50%	2.50%				2.50%
Term Loan due September 2028, Non-Recourse | Term loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate percentage	7.50%					7.50%
Senior Secured Notes due March 2030, Non-Recourse | Senior secured notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate percentage	6.07%					6.07%
Senior Secured Notes due March 2030, Non-Recourse | Senior secured notes | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Instrument	$ 89,654
Term Loan due December 2021, Non-Recourse | Term loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate percentage	2.50%					2.50%