Non-Controlling Interest - Member Interests in Predecessor (Detail)

v2.4.1.9

Non-Controlling Interest - Member Interests in Predecessor (Detail)	3 Months Ended	4 Months Ended	12 Months Ended
	Dec. 31, 2012	Apr. 22, 2013	Sep. 30, 2012
MissionPoint HA Parallel Fund, L.P. [Member]
Other Ownership Interests [Line Items]
Member interests in the Predecessor	70.00%hasi_ProfitSharingRatioPercentageOne / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = hasi_MissionPointHaParallelFundLimitedPartnershipMember	70.00%hasi_ProfitSharingRatioPercentageOne / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = hasi_MissionPointHaParallelFundLimitedPartnershipMember	75.00%hasi_ProfitSharingRatioPercentageOne / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = hasi_MissionPointHaParallelFundLimitedPartnershipMember
Jeffrey W. Eckel, Chief Executive Officer [Member]
Other Ownership Interests [Line Items]
Member interests in the Predecessor	18.00%hasi_ProfitSharingRatioPercentageOne / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = hasi_JeffreywEckelChiefExecutiveOfficerMember	18.00%hasi_ProfitSharingRatioPercentageOne / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = hasi_JeffreywEckelChiefExecutiveOfficerMember	20.00%hasi_ProfitSharingRatioPercentageOne / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = hasi_JeffreywEckelChiefExecutiveOfficerMember
Other Management and Employees of the Predecessor [Member]
Other Ownership Interests [Line Items]
Member interests in the Predecessor	12.00%hasi_ProfitSharingRatioPercentageOne / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = hasi_OtherManagementEmployeesMember	12.00%hasi_ProfitSharingRatioPercentageOne / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = hasi_OtherManagementEmployeesMember	5.00%hasi_ProfitSharingRatioPercentageOne / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = hasi_OtherManagementEmployeesMember