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

Securitization of Financial Assets - Additional Information (Details)

Securitization of Financial Assets - Additional Information (Details)	12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Annual servicing fees (up to)	0.20%
Managed assets	$ 7,200,000,000	$ 6,200,000,000
Securitization credit losses	0	0	$ 0
Payment from debtors to securitization trust	164,342,000	123,979,000
Financial Asset, Equal to or Greater than 90 Days Past Due
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Payment from debtors to securitization trust	0
Asset-backed Securities, Securitized Loans and Receivables
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Managed receivables	4,300,000,000	$ 4,100,000,000
Residual and servicing assets \| Securitization Trust
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Receivable from contracts	$ 100,000,000
Minimum \| Discount Rate
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Discount rates to determine fair market value of underlying assets	0.02
Maximum \| Discount Rate
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Discount rates to determine fair market value of underlying assets	0.08