Annual report pursuant to Section 13 and 15(d)

Business Acquisitions and Related Transactions - Additional Information (Details)

v3.8.0.1
Business Acquisitions and Related Transactions - Additional Information (Details)
$ in Thousands
1 Months Ended 12 Months Ended
Jan. 31, 2017
USD ($)
project
Dec. 31, 2016
USD ($)
Dec. 31, 2017
Business Acquisition [Line Items]      
Number of projects acquired | project 2    
Solar PV project      
Business Acquisition [Line Items]      
Number of projects acquired | project 2    
Initial cash payment | $ $ 2,409 $ 3,575  
Debt assumed | $ $ 5,635 $ 9,503  
Minimum      
Business Acquisition [Line Items]      
Intangible assets amortization period     1 year
Maximum      
Business Acquisition [Line Items]      
Intangible assets amortization period     15 years