Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

v3.19.2
Document and Entity Information - shares
6 Months Ended
Jun. 30, 2019
Jul. 31, 2019
Entity Information [Line Items]    
Entity Registrant Name Ameresco, Inc.  
Entity Central Index Key 0001488139  
Current Fiscal Year End Date --12-31  
Entity Filer Category Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Document Type 10-Q  
Document Period End Date Jun. 30, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q2  
Amendment Flag false  
Entity Shell Company false  
Entity Current Reporting Status Yes  
Common Class A    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   28,412,894
Common Class B    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   18,000,000