Annual report pursuant to Section 13 and 15(d)

Income Taxes - Additional Information (Details)

v2.4.1.9
Income Taxes - Additional Information (Details) (USD $)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Income Tax Contingency [Line Items]      
Deferred tax assets, noncurrent $ 2,357,000us-gaap_DeferredTaxAssetsGrossNoncurrent $ 1,643,000us-gaap_DeferredTaxAssetsGrossNoncurrent  
Deferred tax liabilities, current 3,156,000us-gaap_DeferredTaxLiabilitiesGrossCurrent 2,087,000us-gaap_DeferredTaxLiabilitiesGrossCurrent  
Valuation allowance 3,995,000us-gaap_DeferredTaxAssetsValuationAllowance 1,953,000us-gaap_DeferredTaxAssetsValuationAllowance  
Interest rate swaps 1,419,000amrc_DeferredTaxAssetsDerivativeInstrumentsNet 1,688,000amrc_DeferredTaxAssetsDerivativeInstrumentsNet  
Net operating losses 7,498,000us-gaap_DeferredTaxAssetsOperatingLossCarryforwards 1,948,000us-gaap_DeferredTaxAssetsOperatingLossCarryforwards  
Unrecognized tax benefits 3,700,000us-gaap_UnrecognizedTaxBenefits 9,200,000us-gaap_UnrecognizedTaxBenefits 4,900,000us-gaap_UnrecognizedTaxBenefits
Decrease in unrecognized tax benefit 3,100,000amrc_DecreaseInUnrecognizedTaxBenefitIsReasonablyPossible    
Unrecognized tax benefits that would impact effective tax rate 2,500,000us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate 5,500,000us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate  
Operating loss carryforward 19,116,000us-gaap_DeferredTaxAssetsTaxCreditCarryforwards 9,524,000us-gaap_DeferredTaxAssetsTaxCreditCarryforwards  
Earnings with no repatriation tax 10,300,000amrc_EarningswithNoRepatriationTax    
Amount of interest and penalties related to uncertain tax positions (200,000)us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease (100,000)us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease 300,000us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease
State      
Income Tax Contingency [Line Items]      
Net operating losses 239,000us-gaap_DeferredTaxAssetsOperatingLossCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_StateAndLocalJurisdictionMember 		265,000us-gaap_DeferredTaxAssetsOperatingLossCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_StateAndLocalJurisdictionMember 		 
Operating loss carryforward 8,000,000us-gaap_DeferredTaxAssetsTaxCreditCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_StateAndLocalJurisdictionMember 		   
Federal      
Income Tax Contingency [Line Items]      
Operating loss carryforward 15,200,000us-gaap_DeferredTaxAssetsTaxCreditCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_DomesticCountryMember 		   
Federal tax credit relating to excess stock options 6,000amrc_DeferredTaxAssetsTaxCreditCarryforwardsExcessStockOptions
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_DomesticCountryMember 		   
Net operating loss, related to excess stock options 4,200,000amrc_NetOperatingLossRelatedtoExcessStockOptions
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_DomesticCountryMember 		   
Foreign Tax Authority      
Income Tax Contingency [Line Items]      
Deferred tax assets, foreign 2,337,000us-gaap_OperatingLossCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_ForeignCountryMember 		   
Operating loss carryforward $ 25,600,000us-gaap_DeferredTaxAssetsTaxCreditCarryforwards
/ us-gaap_IncomeTaxAuthorityAxis
= us-gaap_ForeignCountryMember