Annual report pursuant to Section 13 and 15(d)

Project Assets - Additional Information (Details)

v2.4.1.9
Project Assets - Additional Information (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Property, Plant and Equipment [Line Items]      
Property, Plant and Equipment, Other, Net $ 217,772us-gaap_PropertyPlantAndEquipmentOtherNet $ 210,744us-gaap_PropertyPlantAndEquipmentOtherNet  
Proceeds from government grants 3,727amrc_ProceedsFromGovernmentGrants 3,262amrc_ProceedsFromGovernmentGrants 6,024amrc_ProceedsFromGovernmentGrants
Deferred grant income 8,842us-gaap_OtherDeferredCreditsNoncurrent 8,163us-gaap_OtherDeferredCreditsNoncurrent  
Rebates from utility company 0amrc_RebatesFromUtilityCompany 0amrc_RebatesFromUtilityCompany 1,287amrc_RebatesFromUtilityCompany
Project asset depreciation 15,047us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization 12,595us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization 11,229us-gaap_UtilitiesOperatingExpenseDepreciationAndAmortization
Renewal Energy Program      
Property, Plant and Equipment [Line Items]      
Project assets 292,879us-gaap_PropertyPlantAndEquipmentOther
/ us-gaap_RegulatoryAssetAxis
= amrc_RenewalEnergyProgramMember
270,418us-gaap_PropertyPlantAndEquipmentOther
/ us-gaap_RegulatoryAssetAxis
= amrc_RenewalEnergyProgramMember
 
Less - accumulated depreciation and amortization (75,107)us-gaap_PropertyPlantAndEquipmentOtherAccumulatedDepreciation
/ us-gaap_RegulatoryAssetAxis
= amrc_RenewalEnergyProgramMember
(59,674)us-gaap_PropertyPlantAndEquipmentOtherAccumulatedDepreciation
/ us-gaap_RegulatoryAssetAxis
= amrc_RenewalEnergyProgramMember
 
Property, Plant and Equipment, Other, Net $ 217,772us-gaap_PropertyPlantAndEquipmentOtherNet
/ us-gaap_RegulatoryAssetAxis
= amrc_RenewalEnergyProgramMember
$ 210,744us-gaap_PropertyPlantAndEquipmentOtherNet
/ us-gaap_RegulatoryAssetAxis
= amrc_RenewalEnergyProgramMember