Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Earnings Per Share (Details)

v3.7.0.1
Summary of Significant Accounting Policies - Earnings Per Share (Details) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Mar. 31, 2017
Mar. 31, 2016
Dec. 31, 2016
Accounting Policies [Abstract]      
Contracts Receivable Retainage Allowances and Reserves $ 533   $ 887
Net income attributable to Ameresco, Inc. $ (644) $ 1,054  
Basic weighted-average shares outstanding (in shares) 45,513,872 46,742,488  
Effect of dilutive securities:      
Stock options (in shares) 0 117,856  
Diluted weighted-average shares outstanding (in shares) 45,513,872 46,860,344  
Stock options excluded from calculation of dilutive shares as the effect would be anti-dilutive (in shares) 4,158,403 3,297,938