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

Securitization of Receivables - Certain Transactions with Securitization Trusts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Gains on securitizations	$ 25,728	$ 28,915	$ 10,912
Securitization Trust [Member]
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Gains on securitizations	33,000	21,000	17,000
Purchase of receivables securitized	688,000	466,000	532,000
Proceeds from securitizations	721,000	487,000	549,000
Cash received from residual and servicing assets	3,000	4,000	2,000
Securitization Trust [Member] \| Residual Assets [Member]
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Residual and servicing assets included in other assets	$ 72,000	$ 46,000	$ 19,000