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

Nonrecourse Debt - Schedule of Interest Rate Swaps which are Designated as Cash Flow Hedges (Detail)

Nonrecourse Debt - Schedule of Interest Rate Swaps which are Designated as Cash Flow Hedges (Detail) - Cash Flow Hedging [Member] - Interest Rate Swap [Member] - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 17, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Notional Value	$ 450,000,000		$ 431,000,000
Fair Value	1,200,000		1,000,000
HASI SYB Loan Agreement 2015-1 [Member]
Derivatives, Fair Value [Line Items]
Hedged Rate		1.55%
Notional Value	63,000,000		67,000,000
Fair Value	$ 200,000
HASI SYB Loan Agreement 2015-1 [Member] \| Minimum [Member]
Derivatives, Fair Value [Line Items]
Maturity	2015-12
HASI SYB Loan Agreement 2015-1 [Member] \| Maximum [Member]
Derivatives, Fair Value [Line Items]
Maturity	2021-09
HASI SYB Loan Agreement 2015-1 [Member] \| Base Rate [Member]
Derivatives, Fair Value [Line Items]
Base Rate		3 month Libor
HASI SYB Loan Agreement 2015-2 A [Member]
Derivatives, Fair Value [Line Items]
Hedged Rate		1.52%
Notional Value	$ 36,000,000		37,000,000
HASI SYB Loan Agreement 2015-2 A [Member] \| Minimum [Member]
Derivatives, Fair Value [Line Items]
Maturity	2015-12
HASI SYB Loan Agreement 2015-2 A [Member] \| Maximum [Member]
Derivatives, Fair Value [Line Items]
Maturity	2018-12
HASI SYB Loan Agreement 2015-2 A [Member] \| Base Rate [Member]
Derivatives, Fair Value [Line Items]
Base Rate		3 month Libor
HASI SYB Loan Agreement 2015-2 B [Member]
Derivatives, Fair Value [Line Items]
Hedged Rate		2.55%
Notional Value	$ 29,000,000		29,000,000
Fair Value	$ (200,000)		(200,000)
HASI SYB Loan Agreement 2015-2 B [Member] \| Minimum [Member]
Derivatives, Fair Value [Line Items]
Maturity	2018-12
HASI SYB Loan Agreement 2015-2 B [Member] \| Maximum [Member]
Derivatives, Fair Value [Line Items]
Maturity	2024-12
HASI SYB Loan Agreement 2015-2 B [Member] \| Base Rate [Member]
Derivatives, Fair Value [Line Items]
Base Rate		3 month Libor
HASI SYB Loan Agreement 2015-3 [Member]
Derivatives, Fair Value [Line Items]
Hedged Rate		2.34%
Notional Value	$ 119,000,000		119,000,000
Fair Value	$ 800,000		1,000,000
HASI SYB Loan Agreement 2015-3 [Member] \| Minimum [Member]
Derivatives, Fair Value [Line Items]
Maturity	2020-11
HASI SYB Loan Agreement 2015-3 [Member] \| Maximum [Member]
Derivatives, Fair Value [Line Items]
Maturity	2028-08
HASI SYB Loan Agreement 2015-3 [Member] \| Base Rate [Member]
Derivatives, Fair Value [Line Items]
Base Rate		1 month Libor
HASI SYB Loan Agreement 2016-1 A [Member]
Derivatives, Fair Value [Line Items]
Hedged Rate		1.88%
Notional Value	$ 96,000,000		72,000,000
Fair Value	$ 400,000		200,000
HASI SYB Loan Agreement 2016-1 A [Member] \| Minimum [Member]
Derivatives, Fair Value [Line Items]
Maturity	2016-11
HASI SYB Loan Agreement 2016-1 A [Member] \| Maximum [Member]
Derivatives, Fair Value [Line Items]
Maturity	2021-11
HASI SYB Loan Agreement 2016-1 A [Member] \| Base Rate [Member]
Derivatives, Fair Value [Line Items]
Base Rate		3 month Libor
HASI SYB Loan Agreement 2016-1 B [Member]
Derivatives, Fair Value [Line Items]
Hedged Rate		2.73%
Notional Value	$ 107,000,000		$ 107,000,000
HASI SYB Loan Agreement 2016-1 B [Member] \| Minimum [Member]
Derivatives, Fair Value [Line Items]
Maturity	2021-11
HASI SYB Loan Agreement 2016-1 B [Member] \| Maximum [Member]
Derivatives, Fair Value [Line Items]
Maturity	2032-10
HASI SYB Loan Agreement 2016-1 B [Member] \| Base Rate [Member]
Derivatives, Fair Value [Line Items]
Base Rate		3 month Libor