Ameresco, Inc. Quarterly report pursuant to Section 13 or 15(d)

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Legal Proceedings The Company also is involved in a variety of claims and other legal proceedings generally incidental to its normal business activities. While the outcome of any of these proceedings cannot be accurately predicted, the Company does not believe the ultimate resolution of any of these existing matters would have a material adverse effect on its financial condition or results of operations. Commitments as a Result of Acquisitions Related to the Company's acquisition of EEX in the second quarter of 2014, the former owners of EEX (See note 4), who are now employees of the Company, may be entitled to receive up to 4,500 GBP ($6,304 converted as of March 31, 2018) in additional consideration, accounted for as compensation for post-combination services, if the acquired business meets certain financial performance milestones through December 31, 2018. No amounts were accrued as of March 31, 2018 and December 31, 2017, respectively, as milestones are not considered likely to be achieved. The Company has established a reserve reflecting its current estimate of its ultimate exposure to these assessments.