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 |
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| 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 | |
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- Definition Contracts Receivable Retainage Allowances and Reserves No definition available.
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- Definition Effect of dilutive securities: [Abstract] No definition available.
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- References No definition available.
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- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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