| Summary of Disaggregation of Revenue | The following tables provide information about disaggregated revenue by line of business, reportable segments, and geographical region for the three and nine months ended September 30, 2020 and 2019.  
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|  | U.S. Regions |  | U.S. Federal |  | Canada |  | Non-Solar DG |  | All Other |  | Total |  | Line of Business |  | Three Months Ended September 30, 2020 |  
| Project revenue | $ | 79,201 |  |  | $ | 105,444 |  |  | $ | 9,311 |  |  | $ | 7,506 |  |  | $ | 13,941 |  |  | $ | 215,403 |  |  
| O&M revenue | 4,492 |  |  | 11,384 |  |  | — |  |  | 2,009 |  |  | 36 |  |  | 17,921 |  |  
| Energy assets | 9,060 |  |  | 1,325 |  |  | 1,227 |  |  | 18,535 |  |  | 161 |  |  | 30,308 |  |  
| Other | 191 |  |  | 150 |  |  | 1,725 |  |  | 201 |  |  | 16,608 |  |  | 18,875 |  |  
| Total revenues | $ | 92,944 |  |  | $ | 118,303 |  |  | $ | 12,263 |  |  | $ | 28,251 |  |  | $ | 30,746 |  |  | $ | 282,507 |  |  | Three Months Ended September 30, 2019 |  
| Project revenue | $ | 72,667 |  |  | $ | 58,199 |  |  | $ | 9,380 |  |  | $ | 3,059 |  |  | $ | 2,592 |  |  | $ | 145,897 |  |  
| O&M revenue | 4,280 |  |  | 11,123 |  |  | — |  |  | 2,330 |  |  | 88 |  |  | 17,821 |  |  
| Energy assets | 6,699 |  |  | 1,339 |  |  | 1,327 |  |  | 16,421 |  |  | — |  |  | 25,786 |  |  
| Other | 433 |  |  | 597 |  |  | 1,958 |  |  | 65 |  |  | 19,469 |  |  | 22,522 |  |  
| Total revenues | $ | 84,079 |  |  | $ | 71,258 |  |  | $ | 12,665 |  |  | $ | 21,875 |  |  | $ | 22,149 |  |  | $ | 212,026 |  |  | Nine Months Ended September 30, 2020 |  
| Project revenue | $ | 226,734 |  |  | $ | 233,778 |  |  | $ | 24,342 |  |  | $ | 12,881 |  |  | $ | 22,027 |  |  | $ | 519,762 |  |  
| O&M revenue | 13,127 |  |  | 33,765 |  |  | 26 |  |  | 6,144 |  |  | 229 |  |  | 53,291 |  |  
| Energy assets | 25,556 |  |  | 3,549 |  |  | 3,234 |  |  | 54,341 |  |  | 599 |  |  | 87,279 |  |  
| Other | 956 |  |  | 447 |  |  | 5,088 |  |  | 738 |  |  | 50,395 |  |  | 57,624 |  |  
| Total revenues | $ | 266,373 |  |  | $ | 271,539 |  |  | $ | 32,690 |  |  | $ | 74,104 |  |  | $ | 73,250 |  |  | $ | 717,956 |  |  | Nine Months Ended September 30, 2019 |  
| Project revenue | $ | 196,284 |  |  | $ | 134,954 |  |  | $ | 20,112 |  |  | $ | 6,318 |  |  | $ | 8,818 |  |  | $ | 366,486 |  |  
| O&M revenue | 11,580 |  |  | 30,370 |  |  | 5 |  |  | 6,771 |  |  | 109 |  |  | 48,835 |  |  
| Energy assets | 18,063 |  |  | 2,958 |  |  | 2,585 |  |  | 52,612 |  |  | 582 |  |  | 76,800 |  |  
| Other | 1,969 |  |  | 1,055 |  |  | 4,994 |  |  | 669 |  |  | 59,513 |  |  | 68,200 |  |  
| Total revenues | $ | 227,896 |  |  | $ | 169,337 |  |  | $ | 27,696 |  |  | $ | 66,370 |  |  | $ | 69,022 |  |  | $ | 560,321 |  | 
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|  | U.S. Regions |  | U.S. Federal |  | Canada |  | Non-Solar DG |  | All Other |  | Total |  | Geographical Regions |  | Three Months Ended September 30, 2020 |  
| United States | $ | 92,944 |  |  | $ | 118,303 |  |  | $ | 655 |  |  | $ | 28,251 |  |  | $ | 16,173 |  |  | $ | 256,326 |  |  
| Canada | — |  |  | — |  |  | 11,608 |  |  | — |  |  | 22 |  |  | 11,630 |  |  
| Other | — |  |  | — |  |  | — |  |  | — |  |  | 14,551 |  |  | 14,551 |  |  
| Total revenues | $ | 92,944 |  |  | $ | 118,303 |  |  | $ | 12,263 |  |  | $ | 28,251 |  |  | $ | 30,746 |  |  | $ | 282,507 |  |  | Three Months Ended September 30, 2019 |  
| United States | $ | 84,079 |  |  | $ | 71,258 |  |  | $ | 1,023 |  |  | $ | 21,875 |  |  | $ | 17,936 |  |  | $ | 196,171 |  |  
| Canada | — |  |  | — |  |  | 11,642 |  |  | — |  |  | 50 |  |  | 11,692 |  |  
| Other | — |  |  | — |  |  | — |  |  | — |  |  | 4,163 |  |  | 4,163 |  |  
| Total revenues | $ | 84,079 |  |  | $ | 71,258 |  |  | $ | 12,665 |  |  | $ | 21,875 |  |  | $ | 22,149 |  |  | $ | 212,026 |  |  | Nine Months Ended September 30, 2020 |  
| United States | $ | 266,373 |  |  | $ | 271,539 |  |  | $ | 2,173 |  |  | $ | 74,104 |  |  | $ | 49,294 |  |  | $ | 663,483 |  |  
| Canada | — |  |  | — |  |  | 30,517 |  |  | — |  |  | 124 |  |  | 30,641 |  |  
| Other | — |  |  | — |  |  | — |  |  | — |  |  | 23,832 |  |  | 23,832 |  |  
| Total revenues | $ | 266,373 |  |  | $ | 271,539 |  |  | $ | 32,690 |  |  | $ | 74,104 |  |  | $ | 73,250 |  |  | $ | 717,956 |  |  | Nine Months Ended September 30, 2019 |  
| United States | $ | 227,896 |  |  | $ | 169,337 |  |  | $ | 2,281 |  |  | $ | 66,370 |  |  | $ | 56,052 |  |  | $ | 521,936 |  |  
| Canada | — |  |  | — |  |  | 25,415 |  |  | — |  |  | 157 |  |  | 25,572 |  |  
| Other | — |  |  | — |  |  | — |  |  | — |  |  | 12,813 |  |  | 12,813 |  |  
| Total revenues | $ | 227,896 |  |  | $ | 169,337 |  |  | $ | 27,696 |  |  | $ | 66,370 |  |  | $ | 69,022 |  |  | $ | 560,321 |  |  |