Quarterly report pursuant to Section 13 or 15(d)

Nonrecourse Debt - Analysis of Other Nonrecourse Debt by Interest Rate (Detail)

v3.2.0.727
Nonrecourse Debt - Analysis of Other Nonrecourse Debt by Interest Rate (Detail) - USD ($)
$ in Thousands
 6 Months Ended 12 Months Ended
Jun. 30, 2015
Dec. 31, 2014
Debt Instrument [Line Items]    
Other nonrecourse debt, Balance $ 107,510 $ 112,525
Fixed-Rate Promissory Notes, Interest Rates from 2.26% to 5.00% Per Annum [Member]    
Debt Instrument [Line Items]    
Other nonrecourse debt, Balance 34,000  
Fixed-Rate Promissory Notes, Interest Rates from 5.01% to 6.50% Per Annum [Member]    
Debt Instrument [Line Items]    
Other nonrecourse debt, Balance 52,000 58,000
Fixed-Rate Promissory Notes, Interest Rates from 6.51% to 8.00% Per Annum [Member]    
Debt Instrument [Line Items]    
Other nonrecourse debt, Balance $ 22,000 23,000
Fixed-Rate Promissory Notes, Interest Rates from 2.06% to 5.00% Per Annum [Member]    
Debt Instrument [Line Items]    
Other nonrecourse debt, Balance   $ 32,000
Minimum [Member] | Fixed-Rate Promissory Notes, Interest Rates from 2.26% to 5.00% Per Annum [Member]    
Debt Instrument [Line Items]    
Other nonrecourse debt, Maturity 2017  
Minimum [Member] | Fixed-Rate Promissory Notes, Interest Rates from 5.01% to 6.50% Per Annum [Member]    
Debt Instrument [Line Items]    
Other nonrecourse debt, Maturity 2015 2015
Minimum [Member] | Fixed-Rate Promissory Notes, Interest Rates from 6.51% to 8.00% Per Annum [Member]    
Debt Instrument [Line Items]    
Other nonrecourse debt, Maturity 2015 2015
Minimum [Member] | Fixed-Rate Promissory Notes, Interest Rates from 2.06% to 5.00% Per Annum [Member]    
Debt Instrument [Line Items]    
Other nonrecourse debt, Maturity   2015
Maximum [Member] | Fixed-Rate Promissory Notes, Interest Rates from 2.26% to 5.00% Per Annum [Member]    
Debt Instrument [Line Items]    
Other nonrecourse debt, Maturity 2032  
Maximum [Member] | Fixed-Rate Promissory Notes, Interest Rates from 5.01% to 6.50% Per Annum [Member]    
Debt Instrument [Line Items]    
Other nonrecourse debt, Maturity 2031 2031
Maximum [Member] | Fixed-Rate Promissory Notes, Interest Rates from 6.51% to 8.00% Per Annum [Member]    
Debt Instrument [Line Items]    
Other nonrecourse debt, Maturity 2031 2031
Maximum [Member] | Fixed-Rate Promissory Notes, Interest Rates from 2.06% to 5.00% Per Annum [Member]    
Debt Instrument [Line Items]    
Other nonrecourse debt, Maturity   2032