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

Nonrecourse Debt - Additional Information (Detail) - USD ($)			12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Nonrecourse Asset-Backed Debt, Aggregate Principal Amount	$ 692,091,000	$ 663,791,000	$ 692,091,000	$ 663,791,000
Ineffectiveness recorded on designated hedges	0	0
Interest expense			45,241,000	$ 26,385,000	$ 16,655,000
Reclassification out of Accumulated Other Comprehensive Income [Member]
Debt Instrument [Line Items]
Interest expense	0	$ 0
Asset-Backed Nonrecourse Debt Agreement [Member] \| HASI Sustainable Yield Bond 2015-1A ("HASI SYB") [Member]
Debt Instrument [Line Items]
Nonrecourse Asset-Backed Debt, Aggregate Principal Amount	$ 101,000,000		$ 101,000,000
Nonrecourse Asset-Backed Debt, Interest Rate	4.28%		4.28%
Nonrecourse Asset-Backed Debt, Maturity Date			2034-10
Asset-Backed Nonrecourse Debt Agreement [Member] \| HASI Sustainable Yield Bond 2015-1B [Member]
Debt Instrument [Line Items]
Nonrecourse Asset-Backed Debt, Aggregate Principal Amount	$ 18,000,000		$ 18,000,000
Nonrecourse Asset-Backed Debt, Interest Rate	5.00%		5.00%
Nonrecourse Asset-Backed Debt, Maturity Date			2034-10