Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurement - Schedule of Carrying Values and Fair Values of Debt Instruments (Details)

v3.20.2
Fair Value Measurement - Schedule of Carrying Values and Fair Values of Debt Instruments (Details) - USD ($)
$ in Thousands
Sep. 30, 2020
Dec. 31, 2019
Carrying Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value $ 2,484,876 $ 2,254,940
Carrying Value | Bank line of credit    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 224,910 239,485
Carrying Value | Senior debt    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 812,368 625,519
Carrying Value | Subordinated debt    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 594,852 513,938
Carrying Value | Securitization debt    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 852,746 875,998
Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 2,635,870 2,321,409
Fair Value | Bank line of credit    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 224,910 239,485
Fair Value | Senior debt    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 813,561 626,023
Fair Value | Subordinated debt    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 621,211 524,581
Fair Value | Securitization debt    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value $ 976,188 $ 931,320