Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Additional Information (Detail)

v2.4.1.9
Fair Value Measurements - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]    
Cash deposits held in U.S. banks 80us-gaap_CashAndCashEquivalentsFairValueDisclosure $ 70us-gaap_CashAndCashEquivalentsFairValueDisclosure
Bank deposits 77hasi_CashFederalDepositInsuranceCorporationNonInsuredAmount $ 66hasi_CashFederalDepositInsuranceCorporationNonInsuredAmount
Level 3 [Member]    
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]    
Fair value interest rate spreads, minimum 2.00%hasi_FairValueInterestRateSpreadsMinimum
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
 
Fair value interest rate spreads, maximum 5.00%hasi_FairValueInterestRateSpreadsMaximum
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member