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

Securitization of Receivables - Summary of Certain Transactions with Securitization Trusts (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Fair Value Assumption, Date of Securitization or Asset-backed Financing Arrangement, Transferor's Continuing Involvement, Servicing Assets or Liabilities [Line Items]
Gains on securitizations	$ 16,009	$ 11,061
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	20,000	12,000
Purchase of receivables securitized	286,000	195,000
Proceeds from securitizations	306,000	207,000
Cash received from residual and servicing assets	2,000	3,000
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	$ 62,000	$ 29,000