Quarterly report pursuant to Section 13 or 15(d)

Long-term Debt - Additional Information (Detail)

v3.8.0.1
Long-term Debt - Additional Information (Detail) - USD ($)
$ / shares in Units, shares in Millions
 1 Months Ended 3 Months Ended 9 Months Ended
Aug. 31, 2017
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Jan. 31, 2017
Dec. 31, 2016
Debt Instrument [Line Items]              
Non-recourse Asset-Backed Debt, Aggregate Principal Amount   $ 1,076,326,000   $ 1,076,326,000     $ 692,091,000
Total interest expense   17,584,000 $ 10,635,000 46,728,000 $ 32,945,000    
SunPower Corporation [Member] | Residential Solar Loan [Member]              
Debt Instrument [Line Items]              
Outstanding Balance   $ 5,000,000   5,000,000      
Payment of principal and interest on loan       $ 1,000,000      
HASI Sustainable Yield Bond 2015-1A [Member]              
Debt Instrument [Line Items]              
Non-recourse Asset-Backed Debt, Interest Rate   4.28%   4.28%      
Non-recourse Asset-Backed Debt, Maturity Date       2034-10      
HASI Sustainable Yield Bond 2015-1B [Member]              
Debt Instrument [Line Items]              
Non-recourse Asset-Backed Debt, Interest Rate   5.41%   5.41%      
Non-recourse Asset-Backed Debt, Maturity Date       2034-10      
4.125% Convertible Senior Notes Due September 1, 2022 [Member]              
Debt Instrument [Line Items]              
Non-recourse Asset-Backed Debt, Interest Rate 4.125%            
Outstanding Balance $ 145,000,000 $ 146,000,000   $ 146,000,000      
Principal 150,000,000 150,000,000   $ 150,000,000      
Maturity date       Sep. 01, 2022      
Conversion of debt $ 1,000            
Conversion price per share $ 36.7101            
Adjustment for dividends declared $ 0.33            
Conversion of debt equals shares 5.5            
Redemption price, percentage       100.00%      
Redemption description       We have a redemption option to call the Convertible Notes prior to maturity (i) on or after March 1, 2022 and (ii) at any time if such a redemption is deemed reasonably necessary to preserve our qualification as a REIT. The redemption price will be equal to the principal of the notes being redeemed, plus accrued and unpaid interest. In the event of redemption after March 1, 2022, there will be an additional make-whole premium paid to the holder of the redeemed notes unless the redemption is deemed reasonably necessary to preserve our qualification as a REIT.      
Total interest expense   800,000   $ 800,000      
Asset-Backed Nonrecourse Debt Agreement [Member]              
Debt Instrument [Line Items]              
Outstanding Balance   1,076,000,000   1,076,000,000     692,000,000
Asset-Backed Nonrecourse Debt Agreement [Member] | HASI Sustainable Yield Bond 2015-1A [Member]              
Debt Instrument [Line Items]              
Non-recourse Asset-Backed Debt, Aggregate Principal Amount   $ 101,000,000   $ 101,000,000      
Non-recourse Asset-Backed Debt, Interest Rate   4.28%   4.28%      
Non-recourse Asset-Backed Debt, Maturity Date       2034-10      
Outstanding Balance   $ 95,000,000   $ 95,000,000     $ 97,000,000
Asset-Backed Nonrecourse Debt Agreement [Member] | HASI Sustainable Yield Bond 2015-1B [Member]              
Debt Instrument [Line Items]              
Non-recourse Asset-Backed Debt, Aggregate Principal Amount   $ 18,000,000   $ 18,000,000   $ 14,000,000  
Non-recourse Asset-Backed Debt, Interest Rate   5.00%   5.00%      
Non-recourse Asset-Backed Debt, Maturity Date       2034-10      
Outstanding Balance   $ 14,000,000   $ 14,000,000