Quarterly report pursuant to Section 13 or 15(d)

Business Acquisitions and Related Transactions - Additional Information (Details)

v3.10.0.1
Business Acquisitions and Related Transactions - Additional Information (Details)
1 Months Ended 9 Months Ended
Jan. 31, 2017
USD ($)
project
Sep. 30, 2018
USD ($)
project
developer
Dec. 31, 2017
USD ($)
Business Acquisition [Line Items]      
Number of projects acquired | project   2  
Energy assets, net   $ 442,018,000 $ 356,443,000
Cash acquired   $ 0  
Solar Photovoltaic Projects      
Business Acquisition [Line Items]      
Number of projects acquired | project 2    
Initial cash payment $ 2,409,000    
Debt assumed $ 5,635,000    
Solar Projects 1      
Business Acquisition [Line Items]      
Number of projects acquired | project   5  
Initial cash payment   $ 59,097,000  
Number of developers | developer   2  
Fair value of consideration   $ 63,119,000  
Contingent consideration, liability   4,022,000  
Solar Project 2      
Business Acquisition [Line Items]      
Initial cash payment   $ 916,000  
Number of developers | developer   1  
Fair value of consideration   $ 3,019,000  
Undisclosed Name of Acquiree 1      
Business Acquisition [Line Items]      
Initial cash payment   1,901,000  
Debt assumed   0  
Fair value of consideration   $ 2,326,000  
Contingent consideration, liability, acquired receivables, payment period   15 months  
Undisclosed Name of Acquiree 2      
Business Acquisition [Line Items]      
Initial cash payment   $ 1,691,000  
Debt assumed   0  
Contingent consideration, liability   $ 2,000,000  
Contingent consideration, liability, revenue targets, period   5 years  
Contingent consideration, liability, fair value at date of acquisition   $ 555,000  
Minimum      
Business Acquisition [Line Items]      
Estimated useful life   1 year  
Minimum | Solar Photovoltaic Projects      
Business Acquisition [Line Items]      
Estimated useful life   1 year  
Maximum      
Business Acquisition [Line Items]      
Estimated useful life   15 years  
Maximum | Solar Photovoltaic Projects      
Business Acquisition [Line Items]      
Estimated useful life   15 years