Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Narrative (Details)

v3.20.1
Summary of Significant Accounting Policies - Narrative (Details)
$ in Thousands
3 Months Ended
Mar. 31, 2020
USD ($)
Segment
BusinessActivity
Mar. 31, 2019
USD ($)
Jan. 01, 2020
USD ($)
Summary Of Significant Accounting Policies [Line Items]      
Number of operating segments | Segment 1    
Number of business activities | BusinessActivity 1    
Deferred revenue, revenue recognized $ 17,400 $ 14,000  
Contracted but not yet recognized $ 6,900,000    
Revenue expected to recognize over next twelve months, percent 6.00%    
Revenue recognized, term, existing deferred revenue 10 years    
Customer agreement, initial term 22 years    
Customer agreements, initial set up, discount percent 10.00%    
Cumulative effect of adoption of new ASU (No. 2016-13)     $ (1,228)
Retained Earnings      
Summary Of Significant Accounting Policies [Line Items]      
Cumulative effect of adoption of new ASU (No. 2018-02)   $ (740)  
Cumulative effect of adoption of new ASU (No. 2016-13)     $ (1,228)
Minimum      
Summary Of Significant Accounting Policies [Line Items]      
Customer agreement, initial term 20 years    
Maximum      
Summary Of Significant Accounting Policies [Line Items]      
Customer agreement, initial term 25 years    
Solar energy systems | Under Customer Agreements      
Summary Of Significant Accounting Policies [Line Items]      
Average age 4 years