Quarterly report pursuant to Section 13 or 15(d)

Nonrecourse Debt - Schedule of Outstanding Nonrecourse Asset-Backed Debt and Bank Loans (Detail)

v3.4.0.3
Nonrecourse Debt - Schedule of Outstanding Nonrecourse Asset-Backed Debt and Bank Loans (Detail) - USD ($)
$ in Thousands
Dec. 31, 2015
Sep. 30, 2015
Oct. 31, 2014
Dec. 31, 2013
Mar. 31, 2016
Debt Instrument [Line Items]          
Nonrecourse Asset-Backed Debt, Original Principal $ 563,189       $ 551,691
HASI Sustainable Yield Bond 2013-1 [Member]          
Debt Instrument [Line Items]          
Nonrecourse Asset-Backed Debt, Original Principal       $ 100,000  
Nonrecourse Asset-Backed Debt, Interest Rate       2.79%  
Nonrecourse Asset-Backed Debt, Maturity Date       2019-12  
Nonrecourse Asset-Backed Debt, Anticipated Balance at Maturity       $ 57,000  
ABS Loan Agreement [Member]          
Debt Instrument [Line Items]          
Nonrecourse Asset-Backed Debt, Original Principal     $ 115,000    
Nonrecourse Asset-Backed Debt, Interest Rate     5.74%    
Nonrecourse Asset-Backed Debt, Maturity Date     2021-09    
Nonrecourse Asset-Backed Debt, Anticipated Balance at Maturity     $ 17,000    
HASI Sustainable Yield Bond 2015-1 [Member]          
Debt Instrument [Line Items]          
Nonrecourse Asset-Backed Debt, Original Principal   $ 101,000      
Nonrecourse Asset-Backed Debt, Interest Rate   4.28%      
Nonrecourse Asset-Backed Debt, Maturity Date   2034-10      
HASI SYB Loan Agreement 2015-1 [Member]          
Debt Instrument [Line Items]          
Nonrecourse Asset-Backed Debt, Original Principal $ 90,000        
Nonrecourse Asset-Backed Debt, Interest Rate 4.13%        
Nonrecourse Asset-Backed Debt, Maturity Date 2021-12        
HASI SYB Loan Agreement 2015-2 [Member]          
Debt Instrument [Line Items]          
Nonrecourse Asset-Backed Debt, Original Principal $ 42,000        
Nonrecourse Asset-Backed Debt, Interest Rate 4.63%        
Nonrecourse Asset-Backed Debt, Maturity Date 2023-12        
HASI SYB Loan Agreement 2015-3 [Member]          
Debt Instrument [Line Items]          
Nonrecourse Asset-Backed Debt, Original Principal $ 162,000        
Nonrecourse Asset-Backed Debt, Interest Rate 4.92%        
Nonrecourse Asset-Backed Debt, Maturity Date 2020-12        
Nonrecourse Asset-Backed Debt, Anticipated Balance at Maturity $ 132,000