|
Business Acquisitions and Related Transactions - Narrative (Details) (USD $)
|
12 Months Ended | 1 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
Dec. 31, 2012
|
Dec. 31, 2011
|
Dec. 31, 2010
|
Jul. 31, 2012
FAME
|
Apr. 30, 2011
Quantum
|
Aug. 31, 2010
Quantum
|
Sep. 30, 2012
Quantum
|
Sep. 30, 2012
AEG
|
Jul. 31, 2011
AEG
|
Aug. 31, 2011
Ameresco Southwest
|
Dec. 31, 2011
AIS
|
|
| Business Acquisition [Line Items] | |||||||||||
| Initial cash payment | $ 6,150,000 | ||||||||||
| Additional payment | 0 | 1,956,366 | 0 | 1,956,366 | |||||||
| Cash paid | 4,486,950 | 11,993,236 | 50,057,113 | 4,497,141 | |||||||
| Security deposit with third-party escrow agent | 900,000 | 1,000,000 | 900,000 | ||||||||
| Maximum additional consideration for former stockholders of acquiree | 865,000 | 5,000,000 | 5,000,000 | ||||||||
| Fair value of additional consideration for former stockholders of acquiree | 1,652,000 | ||||||||||
| Valuation accrual | $ 1,000,000 | ||||||||||
| X | ||||||||||
|
- Definition
Business Acquisition, Cost of Acquired Entity, Security Deposit in Escrow No definition available.
|
| X | ||||||||||
|
- Definition
Business Combination, Contingent Consideration, Current Commitments Valuation Accural No definition available.
|
| X | ||||||||||
|
- Definition
Fair value, as of the acquisition date, of potential payments under the contingent consideration arrangement including cash and shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Amount of cash paid to acquire the entity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Details
|
| X | ||||||||||
|
- Definition
For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
|
- Definition
Cash outflow representing an adjustment to the purchase price of a previous acquisition. No definition available.
|
| X | ||||||||||
|
- Definition
The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|