Quarterly report pursuant to Section 13 or 15(d)

Equity - Schedule of Common Stock Public Offerings (Detail)

v2.4.1.9
Equity - Schedule of Common Stock Public Offerings (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2015
4/23/2013 Closing Date [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Public offerings of common stock, Closing Date Apr. 23, 2013
Public offerings of common stock, Shares Issued 14,200,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_AwardDateAxis
= hasi_AprilTwentyThreeTwoThousandThirteenClosingDateMember
Public offerings of common stock, Price Per Share $ 12.50us-gaap_SaleOfStockPricePerShare
/ us-gaap_AwardDateAxis
= hasi_AprilTwentyThreeTwoThousandThirteenClosingDateMember
Net proceeds from offering $ 160us-gaap_ProceedsFromIssuanceInitialPublicOffering
/ us-gaap_AwardDateAxis
= hasi_AprilTwentyThreeTwoThousandThirteenClosingDateMember
4/29/2014 Closing Date [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Public offerings of common stock, Closing Date Apr. 29, 2014
Public offerings of common stock, Shares Issued 5,800,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_AwardDateAxis
= hasi_AprilTwentyNineTwoThousandFourteenClosingDateMember
Public offerings of common stock, Price Per Share $ 13.00us-gaap_SaleOfStockPricePerShare
/ us-gaap_AwardDateAxis
= hasi_AprilTwentyNineTwoThousandFourteenClosingDateMember
Net proceeds from follow-on from public offering 70hasi_ProceedsFromIssuanceOfFollowOnPublicOfferingNet
/ us-gaap_AwardDateAxis
= hasi_AprilTwentyNineTwoThousandFourteenClosingDateMember
10/31/2014 Closing Date [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Public offerings of common stock, Closing Date Oct. 31, 2014
Public offerings of common stock, Shares Issued 4,600,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_AwardDateAxis
= hasi_OctoberThirtyOneTwoThousandFourteenClosingDateMember
Public offerings of common stock, Price Per Share $ 13.60us-gaap_SaleOfStockPricePerShare
/ us-gaap_AwardDateAxis
= hasi_OctoberThirtyOneTwoThousandFourteenClosingDateMember
Net proceeds from follow-on from public offering 59hasi_ProceedsFromIssuanceOfFollowOnPublicOfferingNet
/ us-gaap_AwardDateAxis
= hasi_OctoberThirtyOneTwoThousandFourteenClosingDateMember
5/4/2015 Closing Date [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Public offerings of common stock, Closing Date May 04, 2015
Public offerings of common stock, Shares Issued 4,600,000us-gaap_StockIssuedDuringPeriodSharesNewIssues
/ us-gaap_AwardDateAxis
= hasi_MayFourthTwoThousandFifteenClosingDateMember
Public offerings of common stock, Price Per Share $ 18.50us-gaap_SaleOfStockPricePerShare
/ us-gaap_AwardDateAxis
= hasi_MayFourthTwoThousandFifteenClosingDateMember
Net proceeds from follow-on from public offering $ 81hasi_ProceedsFromIssuanceOfFollowOnPublicOfferingNet
/ us-gaap_AwardDateAxis
= hasi_MayFourthTwoThousandFifteenClosingDateMember