Quarterly report pursuant to Section 13 or 15(d)

Credit Facility - Additional Information (Detail)

v3.2.0.727
Credit Facility - Additional Information (Detail) - USD ($)
 1 Months Ended 6 Months Ended
Apr. 30, 2015
Jun. 30, 2015
Dec. 31, 2014
Line of Credit Facility [Line Items]      
Credit facility outstanding   $ 420,496,000 $ 315,748,000
Issuance costs   $ 11,000,000  
Fees for loan agreement description   Fees for each Loan Agreement equal to 0.50%, divided by 360, multiplied by the excess of the available borrowing capacity under each Loan Agreement over the actual amount borrowed under such Loan Agreement.  
Default underlying financings   50.00%  
Qualifying Government and Institutional Loans (G&I Facility) [Member]      
Line of Credit Facility [Line Items]      
Termination of credit facility   Jul. 19, 2019  
Floating interest rate   1.50%  
Qualifying Project Finance Loans (PF Facility) [Member]      
Line of Credit Facility [Line Items]      
Maximum borrowings allowed at any point in time $ 400,000,000    
Line of credit facility, decrease in maximum borrowing capacity $ 350,000,000    
Termination of credit facility   Jul. 19, 2019  
London Interbank Offered Rate   LIBOR plus 2.5%  
Floating interest rate   2.50%  
Applicable valuation percentages   67.00%  
London Interbank Offered Rate (LIBOR) [Member] | Qualifying Government and Institutional Loans (G&I Facility) [Member]      
Line of Credit Facility [Line Items]      
London Interbank Offered Rate   ("LIBOR") plus 1.5%  
Fixed interest rate   1.50%  
London Interbank Offered Rate (LIBOR) [Member] | Qualifying Government and Institutional Loans (G&I Facility) [Member] | 1.5% [Member]      
Line of Credit Facility [Line Items]      
Floating interest rate   1.00%  
London Interbank Offered Rate (LIBOR) [Member] | Qualifying Project Finance Loans (PF Facility) [Member]      
Line of Credit Facility [Line Items]      
Fixed interest rate   2.50%  
London Interbank Offered Rate (LIBOR) [Member] | Qualifying Project Finance Loans (PF Facility) [Member] | 1.5% [Member]      
Line of Credit Facility [Line Items]      
Floating interest rate   1.00%  
Federal Funds Effective Swap Rate [Member] | Qualifying Government and Institutional Loans (G&I Facility) [Member] | 1.5% [Member]      
Line of Credit Facility [Line Items]      
Floating interest rate   0.50%  
Federal Funds Effective Swap Rate [Member] | Qualifying Project Finance Loans (PF Facility) [Member]      
Line of Credit Facility [Line Items]      
London Interbank Offered Rate   Federal Funds Rate plus 0.5%  
Federal Funds Effective Swap Rate [Member] | Qualifying Project Finance Loans (PF Facility) [Member] | 1.5% [Member]      
Line of Credit Facility [Line Items]      
Floating interest rate   0.50%  
Credit Default Option [Member] | Qualifying Government and Institutional Loans (G&I Facility) [Member]      
Line of Credit Facility [Line Items]      
London Interbank Offered Rate   LIBOR plus 2.50%  
Floating interest rate   2.50%  
Credit Default Option [Member] | Qualifying Project Finance Loans (PF Facility) [Member]      
Line of Credit Facility [Line Items]      
London Interbank Offered Rate   LIBOR plus 5.00%  
Floating interest rate   5.00%  
U.S. Federal Government [Member] | Qualifying Government and Institutional Loans (G&I Facility) [Member]      
Line of Credit Facility [Line Items]      
Applicable valuation percentages   85.00%  
Institutional [Member] | Qualifying Government and Institutional Loans (G&I Facility) [Member]      
Line of Credit Facility [Line Items]      
Applicable valuation percentages   80.00%  
Senior Secured Revolving Credit Facility [Member]      
Line of Credit Facility [Line Items]      
Maximum advances on credit facilities   $ 1,500,000,000  
Senior Secured Revolving Credit Facility [Member] | Qualifying Government and Institutional Loans (G&I Facility) [Member]      
Line of Credit Facility [Line Items]      
Maximum advances on credit facilities   450,000,000  
Credit facility outstanding   150,000,000  
Senior Secured Revolving Credit Facility [Member] | Qualifying Project Finance Loans (PF Facility) [Member]      
Line of Credit Facility [Line Items]      
Maximum advances on credit facilities   1,050,000,000  
Credit facility outstanding   $ 400,000,000