Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements - Schedule of Fair Values of Retained Assets, Discount Rates Used in Valuing Assets (Parenthetical) (Detail)

v2.4.1.9
Fair Value Measurements - Schedule of Fair Values of Retained Assets, Discount Rates Used in Valuing Assets (Parenthetical) (Detail)
Dec. 31, 2014
Dec. 31, 2013
Servicing Assets at Fair Value [Line Items]    
Change in discount rate 5.00%hasi_AdverseChangeInDiscountRateForSensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilities 10.00%hasi_AdverseChangeInDiscountRateForSensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilities
Scenario 1 [Member] | Servicing [Member]    
Servicing Assets at Fair Value [Line Items]    
Change in discount rate 5.00%hasi_AdverseChangeInDiscountRateForSensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilities
/ us-gaap_FinancialInstrumentAxis
= hasi_ServicingMember
/ us-gaap_StatementScenarioAxis
= hasi_Scenario1Member 		5.00%hasi_AdverseChangeInDiscountRateForSensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilities
/ us-gaap_FinancialInstrumentAxis
= hasi_ServicingMember
/ us-gaap_StatementScenarioAxis
= hasi_Scenario1Member
Scenario 1 [Member] | Residual Assets [Member]    
Servicing Assets at Fair Value [Line Items]    
Change in discount rate 5.00%hasi_AdverseChangeInDiscountRateForSensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilities
/ us-gaap_FinancialInstrumentAxis
= hasi_ResidualAssetsMember
/ us-gaap_StatementScenarioAxis
= hasi_Scenario1Member 		5.00%hasi_AdverseChangeInDiscountRateForSensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilities
/ us-gaap_FinancialInstrumentAxis
= hasi_ResidualAssetsMember
/ us-gaap_StatementScenarioAxis
= hasi_Scenario1Member
Scenario 2 [Member] | Servicing [Member]    
Servicing Assets at Fair Value [Line Items]    
Change in discount rate 10.00%hasi_AdverseChangeInDiscountRateForSensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilities
/ us-gaap_FinancialInstrumentAxis
= hasi_ServicingMember
/ us-gaap_StatementScenarioAxis
= hasi_Scenario2Member 		10.00%hasi_AdverseChangeInDiscountRateForSensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilities
/ us-gaap_FinancialInstrumentAxis
= hasi_ServicingMember
/ us-gaap_StatementScenarioAxis
= hasi_Scenario2Member
Scenario 2 [Member] | Residual Assets [Member]    
Servicing Assets at Fair Value [Line Items]    
Change in discount rate 10.00%hasi_AdverseChangeInDiscountRateForSensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilities
/ us-gaap_FinancialInstrumentAxis
= hasi_ResidualAssetsMember
/ us-gaap_StatementScenarioAxis
= hasi_Scenario2Member 		10.00%hasi_AdverseChangeInDiscountRateForSensitivityAnalysisOfFairValueOfInterestsContinuedToBeHeldByTransferorServicingAssetsOrLiabilities
/ us-gaap_FinancialInstrumentAxis
= hasi_ResidualAssetsMember
/ us-gaap_StatementScenarioAxis
= hasi_Scenario2Member