Annual report pursuant to Section 13 and 15(d)

Business Acquisitions and Related Transactions - Purchase Price Allocation (Details)

v2.4.1.9
Business Acquisitions and Related Transactions - Purchase Price Allocation (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jun. 30, 2013
Dec. 31, 2011
Business Acquisition [Line Items]          
Goodwill $ 60,479us-gaap_Goodwill $ 53,074us-gaap_Goodwill $ 48,969us-gaap_Goodwill    
Total, net of cash received 13,903us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired 9,838us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired 4,012us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired    
EEX          
Business Acquisition [Line Items]          
Cash 0us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Accounts receivable 1,432us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Costs and estimated earnings in excess of billings 186amrc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentAssetsCostsandEstimatedEarningsinExcessofBillings
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Prepaid expenses and other current assets 295us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Property and equipment and project assets 123us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Goodwill 7,590us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Intangible assets(1) 7,208us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Accounts payable (1,719)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Accrued liabilities (459)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Billings in excess of cost and estimated earnings (752)amrc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesBillingsinExcessofCostsandEstimatedEarnings
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Deferred taxes and other liabilities 0us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Purchase price 13,904us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Total, net of cash received 13,904us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
Total fair value of consideration 13,904us-gaap_BusinessCombinationConsiderationTransferred1
/ us-gaap_BusinessAcquisitionAxis
= amrc_EEXMember
       
ESP          
Business Acquisition [Line Items]          
Cash   1,292us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
     
Accounts receivable   772us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
     
Costs and estimated earnings in excess of billings   665amrc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentAssetsCostsandEstimatedEarningsinExcessofBillings
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
     
Prepaid expenses and other current assets   1,169us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
     
Property and equipment and project assets   138us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
     
Goodwill   3,682us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
  2,632us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
 
Intangible assets(1)   5,099us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
     
Accounts payable   (413)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
     
Accrued liabilities   (607)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
     
Billings in excess of cost and estimated earnings   (108)amrc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesBillingsinExcessofCostsandEstimatedEarnings
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
     
Deferred taxes and other liabilities   (1,158)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
     
Purchase price   10,531us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
  8,765us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
 
Total, net of cash received   9,239us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
     
Total fair value of consideration   10,531us-gaap_BusinessCombinationConsiderationTransferred1
/ us-gaap_BusinessAcquisitionAxis
= amrc_ESPMember
     
FAME          
Business Acquisition [Line Items]          
Cash     810us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
   
Accounts receivable     321us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
   
Costs and estimated earnings in excess of billings     0amrc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentAssetsCostsandEstimatedEarningsinExcessofBillings
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
   
Prepaid expenses and other current assets     108us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
   
Property and equipment and project assets     43us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
   
Goodwill     1,887us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
  1,887us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
Intangible assets(1)     2,100us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
   
Accounts payable     (6)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesAccountsPayable
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
   
Accrued liabilities     (618)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOther
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
   
Billings in excess of cost and estimated earnings     (158)amrc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedCurrentLiabilitiesBillingsinExcessofCostsandEstimatedEarnings
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
   
Deferred taxes and other liabilities     0us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
   
Purchase price     4,487us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
   
Total, net of cash received     3,677us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember
   
Total fair value of consideration     $ 4,487us-gaap_BusinessCombinationConsiderationTransferred1
/ us-gaap_BusinessAcquisitionAxis
= amrc_FameFacilitySoftwareSolutionsIncMember