Annual report pursuant to Section 13 and 15(d)

Investment Fund (Details)

v3.6.0.2
Investment Fund (Details) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Cash    
Variable Interest Entity [Line Items]    
Variable interest entity, assets $ 1,157 $ 0
Restricted Cash    
Variable Interest Entity [Line Items]    
Variable interest entity, assets 1,554 5,419
Accounts Receivable    
Variable Interest Entity [Line Items]    
Variable interest entity, assets 80 0
Costs and Estimated Earnings in Excess of Billings    
Variable Interest Entity [Line Items]    
Variable interest entity, assets 50 0
Prepaid Expenses and Other Current Assets    
Variable Interest Entity [Line Items]    
Variable interest entity, assets 50 25
Project Assets    
Variable Interest Entity [Line Items]    
Variable interest entity, assets 32,185 32,657
Other Assets    
Variable Interest Entity [Line Items]    
Variable interest entity, assets 77 112
Accrued Liabilities    
Variable Interest Entity [Line Items]    
Variable interest entity, liabilities $ 165 $ 0