Quarterly report pursuant to Section 13 or 15(d)

Investment Funds (Details)

v3.10.0.1
Investment Funds (Details)
$ in Thousands
Sep. 30, 2018
USD ($)
fund
Jun. 30, 2018
fund
Dec. 31, 2017
USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]      
Investment funds, purchase of solar energy systems | fund 3 3  
Cash      
Variable Interest Entity [Line Items]      
Variable interest entity, carrying amount, assets $ 3,515   $ 444
Restricted cash      
Variable Interest Entity [Line Items]      
Variable interest entity, carrying amount, assets 1,690   1,553
Accounts receivable      
Variable Interest Entity [Line Items]      
Variable interest entity, carrying amount, assets 554   328
Costs and estimated earnings in excess of billings      
Variable Interest Entity [Line Items]      
Variable interest entity, carrying amount, assets 278   360
Prepaid expenses and other current assets      
Variable Interest Entity [Line Items]      
Variable interest entity, carrying amount, assets 25   8
Energy assets, net      
Variable Interest Entity [Line Items]      
Variable interest entity, carrying amount, assets 106,818   55,712
Accounts payable      
Variable Interest Entity [Line Items]      
Variable interest entity, carrying amount, liabilities 3,891   764
Accrued liabilities      
Variable Interest Entity [Line Items]      
Variable interest entity, carrying amount, liabilities 29   74
Other liabilities      
Variable Interest Entity [Line Items]      
Variable interest entity, carrying amount, liabilities 1,543   75
Long term debt, net deferred financing fees      
Variable Interest Entity [Line Items]      
Variable interest entity, carrying amount, liabilities $ 28,055   $ 0