Quarterly report pursuant to Section 13 or 15(d)

Investment Funds (Details)

v3.8.0.1
Investment Funds (Details) - USD ($)
$ in Thousands
Mar. 31, 2018
Dec. 31, 2017
Cash    
Variable Interest Entity [Line Items]    
Variable interest entity, carrying amount, assets $ 462 $ 444
Restricted cash    
Variable Interest Entity [Line Items]    
Variable interest entity, carrying amount, assets 1,605 1,553
Accounts receivable    
Variable Interest Entity [Line Items]    
Variable interest entity, carrying amount, assets 139 328
Costs and estimated earnings in excess of billings    
Variable Interest Entity [Line Items]    
Variable interest entity, carrying amount, assets 556 360
Prepaid expenses and other current assets    
Variable Interest Entity [Line Items]    
Variable interest entity, carrying amount, assets 8 8
Energy assets, net    
Variable Interest Entity [Line Items]    
Variable interest entity, carrying amount, assets 55,361 55,712
Accounts payable    
Variable Interest Entity [Line Items]    
Variable interest entity, consolidated, carrying amount, liabilities 137 764
Accrued liabilities    
Variable Interest Entity [Line Items]    
Variable interest entity, consolidated, carrying amount, liabilities 95 74
Other liabilities    
Variable Interest Entity [Line Items]    
Variable interest entity, consolidated, carrying amount, liabilities $ 85 $ 75