Quarterly report pursuant to Section 13 or 15(d)

Equity - Summary of Unvested Shares of Restricted Common Stock (Detail)

v2.4.1.9
Equity - Summary of Unvested Shares of Restricted Common Stock (Detail) (Restricted Incentive [Member], USD $)
In Millions, except Share data, unless otherwise specified
3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Restricted Incentive [Member]
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Beginning Balance, Restricted Shares of Common Stock 964,820us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
598,815us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Granted, Restricted Shares of Common Stock 564,716us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
529,100us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Vested, Restricted Shares of Common Stock (9,250)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
(149,709)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Forfeited, Restricted Shares of Common Stock   (13,386)us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Ending Balance, Restricted Shares of Common Stock 1,520,286us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
964,820us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Beginning Balance, Weighted Average Share Price $ 13.41us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
$ 12.50us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Granted, Weighted Average Share Price $ 17.27us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
$ 14.18us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Vested, Weighted Average Share Price $ 14.61us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
$ 12.50us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Forfeited, Weighted Average Share Price   $ 12.99us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Ending Balance, Weighted Average Share Price $ 14.84us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
$ 13.41us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Beginning Balance, Fair Value of Restricted Shares of Common Stock $ 12.9hasi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
$ 7.5hasi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Granted, Fair Value of Restricted Shares of Common Stock 9.8hasi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
7.5hasi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Vested, Fair Value of Restricted Shares of Common Stock (0.1)hasi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
(1.9)hasi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Forfeited, Fair Value of Restricted Shares of Common Stock   (0.2)hasi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
Ending Balance, Fair Value of Restricted Shares of Common Stock $ 22.6hasi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember
$ 12.9hasi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedFairValue
/ us-gaap_AwardTypeAxis
= us-gaap_RestrictedStockMember