Annual report pursuant to Section 13 and 15(d)

Investment Funds (Details)

v3.8.0.1
Investment Funds (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Cash    
Variable Interest Entity [Line Items]    
Variable interest entity, assets $ 444 $ 1,157
Restricted cash    
Variable Interest Entity [Line Items]    
Variable interest entity, assets 1,553 1,554
Accounts receivable    
Variable Interest Entity [Line Items]    
Variable interest entity, assets 328 80
Costs and estimated earnings in excess of billings    
Variable Interest Entity [Line Items]    
Variable interest entity, assets 360 50
Prepaid expenses and other current assets    
Variable Interest Entity [Line Items]    
Variable interest entity, assets 8 50
Energy assets, net    
Variable Interest Entity [Line Items]    
Variable interest entity, assets 55,712 32,185
Other assets    
Variable Interest Entity [Line Items]    
Variable interest entity, assets 0 77
Accounts payable    
Variable Interest Entity [Line Items]    
Variable interest entity, liabilities 764 102
Accrued liabilities    
Variable Interest Entity [Line Items]    
Variable interest entity, liabilities 74 63
Other liabilities    
Variable Interest Entity [Line Items]    
Variable interest entity, liabilities $ 75 $ 0