Annual report pursuant to Section 13 and 15(d)

Indebtedness - Additional Information (Details)

v3.20.4
Indebtedness - Additional Information (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Debt Instrument [Line Items]    
Loan outstanding balance $ 4,796,145 $ 2,254,940
Bank Line of Credit | Recourse debt    
Debt Instrument [Line Items]    
Secured borrowing, carrying amount 250,000  
Minimum unencumbered liquid assets to be maintained 25,000  
Minimum required quarter-end unencumbered cash balance $ 35,000  
Interest coverage ratio 350.00%  
Bank Line of Credit | Recourse debt | LIBOR    
Debt Instrument [Line Items]    
Interest rate during period 3.25%  
Bank Line of Credit | Recourse debt | Base Rate    
Debt Instrument [Line Items]    
Interest rate 2.25%  
Bank Line of Credit | Recourse debt | Federal Funds Rate    
Debt Instrument [Line Items]    
Interest rate 0.50%  
Bank Line of Credit | Recourse debt | Prime Rate    
Debt Instrument [Line Items]    
Interest rate 1.00%  
Senior revolving and delayed draw loans | Non Recourse Debt    
Debt Instrument [Line Items]    
Aggregate principal amount $ 1,100,000  
Senior revolving and delayed draw loans | Non Recourse Debt | Revolving loan    
Debt Instrument [Line Items]    
Loan outstanding balance 60,000  
Aggregate principal amount 200,000  
Minimum required fiscal unencumbered cash balance $ 30,000  
Senior Revolving and Delayed Draw Loans, LIBOR Loans | Non Recourse Debt | LIBOR | Revolving loan    
Debt Instrument [Line Items]    
Debt instrument, basis spread on variable rate 3.25%  
Senior Revolving and Delayed Draw Loans, LIBOR Loans | Non Recourse Debt | LIBOR Floor Rate | Revolving loan    
Debt Instrument [Line Items]    
Debt instrument, basis spread on variable rate 0.00%  
Senior Revolving and Delayed Draw Loans, Base Rate Loans | Non Recourse Debt | LIBOR | Revolving loan    
Debt Instrument [Line Items]    
Debt instrument, basis spread on variable rate 1.00%  
Senior Revolving and Delayed Draw Loans, Base Rate Loans | Non Recourse Debt | Base Rate | Revolving loan    
Debt Instrument [Line Items]    
Debt instrument, basis spread on variable rate 2.25%  
Senior Revolving and Delayed Draw Loans, Base Rate Loans | Non Recourse Debt | Federal Funds Rate | Revolving loan    
Debt Instrument [Line Items]    
Debt instrument, basis spread on variable rate 0.50%  
Senior Revolving and Delayed Draw Loans, Base Rate Loans | Non Recourse Debt | LIBOR Floor Rate | Revolving loan    
Debt Instrument [Line Items]    
Debt instrument, basis spread on variable rate 0.00%  
Securitized loans | Non Recourse Debt    
Debt Instrument [Line Items]    
Loan outstanding balance $ 123,400