HA Sustainable Infrastructure Capital, Inc. Annual report pursuant to Section 13 and 15(d)

Annual report pursuant to Section 13 and 15(d)

The Company - Additional Information (Detail)

The Company - Additional Information (Detail) (USD $)	0 Months Ended		1 Months Ended	3 Months Ended	12 Months Ended			0 Months Ended	1 Months Ended	0 Months Ended
The Company - Additional Information (Detail) (USD $)	May 23, 2013	Apr. 23, 2013	May 31, 2014 acre	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Sep. 30, 2012	Oct. 20, 2014 State Company	Oct. 31, 2014 Project State	Oct. 01, 2014	Apr. 29, 2014
Organization [Line Items]
Initial public offering, shares		14,200,000
Net proceeds from offering	$ 9,500,000	$ 160,000,000
Underwriters shares of common stock	818,356
Share issued pursuant to underwriter									600,000		750,000
Follow-on public offering, shares									4,600,000hasi_FollowOnPublicOfferingShares		5,750,000hasi_FollowOnPublicOfferingShares
Follow-on public offering, price per share									$ 13.60hasi_FollowOnPublicOfferingSharesPrice		$ 13.00hasi_FollowOnPublicOfferingSharesPrice
Net proceeds from follow-on from public offering									58,900,000		70,400,000
Acquisition date					May 28, 2014
Business combination consideration paid			106,700,000
Acquisition completed date					Jan. 01, 2013
Area of land acquired			10,500hasi_AreaOfLandAcquired
Acquisition related costs			2,500,000
Liabilities assumed in connection with acquisitions					0
Rental Income					3,175,000
Interest Income, Financing receivables				2,834,000us-gaap_InterestIncomeOperating	23,178,000us-gaap_InterestIncomeOperating	15,468,000us-gaap_InterestIncomeOperating	11,848,000us-gaap_InterestIncomeOperating
Strong Upwind Holdings LLC [Member]
Organization [Line Items]
Project investment amount								144,000,000	144,000,000
Number of limited liability companies								4
Number of operating projects									10
Number of States								5	5
Strong Upwind Holdings LLC [Member] \| Minimum [Member]
Organization [Line Items]
Ownership interest based on voting percentage									4.00%	4.00%
Strong Upwind Holdings LLC [Member] \| Maximum [Member]
Organization [Line Items]
Ownership interest based on voting percentage								17.50%	17.50%
Strong Upwind Holdings LLC [Member] \| Wind Project Investment [Member]
Organization [Line Items]
Number of limited liability companies									4
Number of operating projects								10
AWCC [Member]
Organization [Line Items]
Business combination consideration paid			19,400,000
Working capital adjustment					200,000
Rental Income					3,200,000
Interest Income, Financing receivables					$ 1,500,000
Solar [Member]
Organization [Line Items]
Number of projects			20
Wind [Member]
Organization [Line Items]
Number of projects			57