Quarterly report pursuant to Section 13 or 15(d)

Our Portfolio - Financing Receivables, Investments, Real Estate and Equity Method Investments - Additional Information (Detail)

v2.4.1.9
Our Portfolio - Financing Receivables, Investments, Real Estate and Equity Method Investments - Additional Information (Detail) (USD $)
 3 Months Ended 12 Months Ended 1 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Apr. 30, 2015
Dec. 31, 2013
May 31, 2013
Financing Receivable, Recorded Investment [Line Items]            
Financing receivables and investments $ 885,000,000us-gaap_LoansAndLeasesReceivableNetReportedAmount          
Deferred funding obligations 72,336,000us-gaap_ContractualObligation   88,288,000us-gaap_ContractualObligation      
Restricted cash 1,600,000hasi_RestrictedCashAndCashEquivalent   3,000,000hasi_RestrictedCashAndCashEquivalent      
Financing receivable allowance 1,200,000us-gaap_AllowanceForNotesAndLoansReceivableCurrent          
Maximum agreed recovery amount     2,000,000hasi_LoanAndLeaseLossAgreedMaximumRecovery      
Charged off of receivable against allowance     9,800,000us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs      
Allowance for credit losses 1,200,000us-gaap_FinancingReceivableAllowanceForCreditLosses   1,200,000us-gaap_FinancingReceivableAllowanceForCreditLosses      
Loan expected recovery 800,000hasi_LoanAndLeaseLossExpectedRecovery          
Maximum exposure loss for variable interest entity 800,000hasi_VariableInterestEntityMaximumExposureToLoss   800,000hasi_VariableInterestEntityMaximumExposureToLoss      
Accrued interest income 0us-gaap_InterestExpenseRelatedParty 0us-gaap_InterestExpenseRelatedParty        
Other financing receivables on non accrual status 0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus   0us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus      
Provision for credit losses 0hasi_ProvisionForCreditLosses 0hasi_ProvisionForCreditLosses        
Loan modifications that qualify as trouble debt restructurings 0us-gaap_FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown 0us-gaap_FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown        
Debt and Real Estate Portfolio [Member]            
Financing Receivable, Recorded Investment [Line Items]            
% of Debt and Real Estate Portfolio 98.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= hasi_PortfolioMember 		         
Minimum [Member]            
Financing Receivable, Recorded Investment [Line Items]            
Lease agreement expected expirations, term 2047          
Long term land lease agreements expiration dates range 2033          
Long term land lease agreements extended expiration dates range 2047          
Maximum [Member]            
Financing Receivable, Recorded Investment [Line Items]            
Lease agreement expected expirations, term 2061          
Long term land lease agreements expiration dates range 2044          
Long term land lease agreements extended expiration dates range 2061          
Energy Source LLC [Member]            
Financing Receivable, Recorded Investment [Line Items]            
Financing receivable allowance         11,000,000us-gaap_AllowanceForNotesAndLoansReceivableCurrent
/ dei_LegalEntityAxis
= hasi_EnergySourceMember 		 
Financing receivable allowance, face amount           24,000,000hasi_LoansReceivableFaceAmount
/ dei_LegalEntityAxis
= hasi_EnergySourceMember
Financial receivable average outstanding balance 11,800,000us-gaap_NotesAndLoansReceivableGrossCurrent
/ dei_LegalEntityAxis
= hasi_EnergySourceMember 		         
Energy Source LLC [Member] | Subsequent Event [Member]            
Financing Receivable, Recorded Investment [Line Items]            
Cash received from pending land sale from unrelated third party       400,000hasi_AmountReceivedFromPendingLandSaleFromUnrelatedThirdParty
/ dei_LegalEntityAxis
= hasi_EnergySourceMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember 		   
Additional amount receivable upon the closing of the land sale       $ 400,000hasi_AdditionalAmountReceivableOnSettlementOfPendingLandSale
/ dei_LegalEntityAxis
= hasi_EnergySourceMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember