Annual report pursuant to Section 13 and 15(d)

Fair Value of Financial Instruments - Schedule of Fair Value Hierarchy Of Outstanding Borrowings (Details)

v3.24.0.1
Fair Value of Financial Instruments - Schedule of Fair Value Hierarchy Of Outstanding Borrowings (Details) - USD ($)
$ in Thousands
Dec. 31, 2023
Dec. 31, 2022
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs $ 1,554,869 $ 1,574,351
Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 1,554,869 1,574,351
Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 1,450,995 1,434,445
SBA Debentures | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 170,323 169,738
SBA Debentures | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 142,011 155,257
July 2024 Notes | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 104,828 104,533
July 2024 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 105,755 102,019
February 2025 Notes | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 49,866 49,751
February 2025 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 49,144 47,044
June 2025 Notes | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 69,757 69,595
June 2025 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 67,198 64,198
June 2025 3-Year Notes | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 49,771 49,616
June 2025 3-Year Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 48,983 47,528
March 2026 A Notes | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 49,795 49,700
March 2026 A Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 47,702 45,512
March 2026 B Notes | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 49,776 49,673
March 2026 B Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 47,759 45,588
September 2026 Notes | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 322,339 321,358
September 2026 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 288,711 269,509
January 2027 Notes | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 345,935 344,604
January 2027 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 315,832 296,826
2031 Asset-Backed Notes | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 148,544 147,957
2031 Asset-Backed Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 142,500 142,620
2033 Notes | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 38,935 38,826
2033 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 40,400 39,344
MUFG Bank Facility | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 61,000 107,000
MUFG Bank Facility | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 61,000 107,000
SMBC Facility | Carrying Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Net of debt issuance costs 94,000 72,000
SMBC Facility | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 94,000 72,000
Identical Assets Level 1 | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Identical Assets Level 1 | SBA Debentures | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Identical Assets Level 1 | July 2024 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Identical Assets Level 1 | February 2025 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Identical Assets Level 1 | June 2025 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Identical Assets Level 1 | June 2025 3-Year Notes    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0  
Identical Assets Level 1 | June 2025 3-Year Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value   0
Identical Assets Level 1 | March 2026 A Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Identical Assets Level 1 | March 2026 B Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Identical Assets Level 1 | September 2026 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Identical Assets Level 1 | January 2027 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Identical Assets Level 1 | 2031 Asset-Backed Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Identical Assets Level 1 | 2033 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Identical Assets Level 1 | MUFG Bank Facility | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Identical Assets Level 1 | SMBC Facility | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Observable Inputs Level 2 | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 182,900 181,964
Observable Inputs Level 2 | SBA Debentures | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Observable Inputs Level 2 | July 2024 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Observable Inputs Level 2 | February 2025 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Observable Inputs Level 2 | June 2025 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Observable Inputs Level 2 | June 2025 3-Year Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Observable Inputs Level 2 | March 2026 A Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Observable Inputs Level 2 | March 2026 B Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Observable Inputs Level 2 | September 2026 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Observable Inputs Level 2 | January 2027 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Observable Inputs Level 2 | 2031 Asset-Backed Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 142,500 142,620
Observable Inputs Level 2 | 2033 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 40,400 39,344
Observable Inputs Level 2 | MUFG Bank Facility | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Observable Inputs Level 2 | SMBC Facility | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Unobservable Inputs Level 3 | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 1,268,095 1,252,481
Unobservable Inputs Level 3 | SBA Debentures | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 142,011 155,257
Unobservable Inputs Level 3 | July 2024 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 105,755 102,019
Unobservable Inputs Level 3 | February 2025 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 49,144 47,044
Unobservable Inputs Level 3 | June 2025 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 67,198 64,198
Unobservable Inputs Level 3 | June 2025 3-Year Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 48,983 47,528
Unobservable Inputs Level 3 | March 2026 A Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 47,702 45,512
Unobservable Inputs Level 3 | March 2026 B Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 47,759 45,588
Unobservable Inputs Level 3 | September 2026 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 288,711 269,509
Unobservable Inputs Level 3 | January 2027 Notes    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 315,832  
Unobservable Inputs Level 3 | January 2027 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value   296,826
Unobservable Inputs Level 3 | 2031 Asset-Backed Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Unobservable Inputs Level 3 | 2033 Notes | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 0 0
Unobservable Inputs Level 3 | MUFG Bank Facility | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value 61,000 107,000
Unobservable Inputs Level 3 | SMBC Facility | Fair Value    
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]    
Approximate Fair Value $ 94,000 $ 72,000