Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

v3.19.1
Document and Entity Information - shares
3 Months Ended
Mar. 31, 2019
Apr. 30, 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 Mar. 31, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1  
Amendment Flag false  
Common Class A    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   30,473,210
Common Class B    
Entity Information [Line Items]    
Entity Common Stock, Shares Outstanding (in shares)   18,000,000