Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.3
Fair Value Measurement - Schedule of Carrying Values and Fair Values of Debt Instruments (Details) - USD ($)
$ in Thousands
Sep. 30, 2019
Dec. 31, 2018
Carrying Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value $ 2,045,309 $ 1,748,922
Carrying Value | Bank line of credit    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 239,035 247,000
Carrying Value | Senior debt    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 853,293 828,517
Carrying Value | Subordinated debt    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 374,556 273,337
Carrying Value | Securitization debt    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 578,425 400,068
Fair Value    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 2,103,759 1,743,002
Fair Value | Bank line of credit    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 239,035 247,000
Fair Value | Senior debt    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 853,749 828,309
Fair Value | Subordinated debt    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value 389,404 272,937
Fair Value | Securitization debt    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt instrument, fair value $ 621,571 $ 394,756