Annual report pursuant to Section 13 and 15(d)

Nonrecourse Debt - Additional Information Related to Other Nonrecourse Debt by Interest Rate (Parenthetical) (Detail)

v3.3.1.900
Nonrecourse Debt - Additional Information Related to Other Nonrecourse Debt by Interest Rate (Parenthetical) (Detail)
Dec. 31, 2015
Dec. 31, 2014
Fixed-Rate Promissory Notes, Interest Rates from 2.26% to 5.00% Per Annum [Member] | Minimum [Member]    
Debt Instrument [Line Items]    
Fixed-rate promissory notes, interest rates 2.26%  
Fixed-Rate Promissory Notes, Interest Rates from 2.26% to 5.00% Per Annum [Member] | Maximum [Member]    
Debt Instrument [Line Items]    
Fixed-rate promissory notes, interest rates 5.00%  
Fixed-Rate Promissory Notes, Interest Rates from 5.01% to 6.50% Per Annum [Member] | Minimum [Member]    
Debt Instrument [Line Items]    
Fixed-rate promissory notes, interest rates 5.01% 5.01%
Fixed-Rate Promissory Notes, Interest Rates from 5.01% to 6.50% Per Annum [Member] | Maximum [Member]    
Debt Instrument [Line Items]    
Fixed-rate promissory notes, interest rates 6.50% 6.50%
Fixed-Rate Promissory Notes, Interest Rates from 6.51% to 8.00% Per Annum [Member] | Minimum [Member]    
Debt Instrument [Line Items]    
Fixed-rate promissory notes, interest rates 6.51% 6.51%
Fixed-Rate Promissory Notes, Interest Rates from 6.51% to 8.00% Per Annum [Member] | Maximum [Member]    
Debt Instrument [Line Items]    
Fixed-rate promissory notes, interest rates 8.00% 8.00%
Fixed-Rate Promissory Notes, Interest Rates from 2.06% to 5.00% Per Annum [Member] | Minimum [Member]    
Debt Instrument [Line Items]    
Fixed-rate promissory notes, interest rates   2.06%
Fixed-Rate Promissory Notes, Interest Rates from 2.06% to 5.00% Per Annum [Member] | Maximum [Member]    
Debt Instrument [Line Items]    
Fixed-rate promissory notes, interest rates   5.00%