Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Sale-Leaseback (Details)

v3.4.0.3
Summary of Significant Accounting Policies - Sale-Leaseback (Details)
3 Months Ended
Mar. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Mar. 31, 2015
USD ($)
project
Sale Leaseback Transaction [Line Items]      
Proceeds from sale of solar-PV projects $ 3,541,000   $ 7,581,000
Solar Photovoltaic Projects      
Sale Leaseback Transaction [Line Items]      
Maximum combined funding amount 50,000,000    
Number of solar photovoltaic projects sold | project     2
Proceeds from sale of solar-PV projects $ 3,541,000 $ 4,925,000 $ 7,581,000
Percentage of fair value threshold, integral equipment 10.00%    
Sale leaseback transaction, deferred gain $ 708,000   $ 1,029,000
Lease terms     20 years
Sale leaseback transaction, deferred loss   1,421,000  
Capital lease assets 1,406,000 $ 3,299,000  
Capital lease liabilities 3,299,000   $ 3,511,000
Solar Photovoltaic Projects | Minimum      
Sale Leaseback Transaction [Line Items]      
Monthly payments 8,000   7,000
Solar Photovoltaic Projects | Maximum      
Sale Leaseback Transaction [Line Items]      
Monthly payments $ 139,000   $ 348,000