Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Details)

v2.4.1.9
Summary of Significant Accounting Policies - Additional Information (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Accounting Policies [Abstract]      
Restricted cash, noncurrent $ 10,636us-gaap_RestrictedCashAndCashEquivalentsNoncurrent $ 11,295us-gaap_RestrictedCashAndCashEquivalentsNoncurrent  
Maximum exposure, per participant 75,000amrc_LossContingencySelfInsuranceMaximumExposurePerParticipant    
Interest costs capitalized 518us-gaap_InterestCostsCapitalized 1,825us-gaap_InterestCostsCapitalized 2,104us-gaap_InterestCostsCapitalized
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
Carrying value of fixed-rate long-term debt in excess of fair value $ 70amrc_LongTermDebtCarryingValueInExcessOfFairValue