Summary of Significant Accounting Policies - Components of the Company's investment income (Details) - USD ($) $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2022 |
Sep. 30, 2022 |
Jun. 30, 2022 |
Mar. 31, 2022 |
Dec. 31, 2021 |
Sep. 30, 2021 |
Jun. 30, 2021 |
Mar. 31, 2021 |
Dec. 31, 2020 |
Sep. 30, 2020 |
Jun. 30, 2020 |
Mar. 31, 2020 |
Dec. 31, 2022 |
Dec. 31, 2021 |
Dec. 31, 2020 |
|
| Summary of Significant Accounting Policies | |||||||||||||||
| Interest income | $ 41,449 | $ 35,738 | $ 42,640 | ||||||||||||
| PIK interest income | 6,689 | 8,320 | 8,776 | ||||||||||||
| Dividend income | 4,161 | 5,712 | 4,557 | ||||||||||||
| Fee income | 2,380 | 1,267 | 3,222 | ||||||||||||
| Prepayment gain (loss) | 803 | 1,691 | 1,133 | ||||||||||||
| Accretion of discounts and amortization of premium | 1,084 | 1,102 | 1,253 | ||||||||||||
| Total investment income | $ 15,164 | $ 15,916 | $ 12,995 | $ 12,491 | $ 13,039 | $ 15,214 | $ 12,364 | $ 13,213 | $ 12,552 | $ 13,385 | $ 20,642 | $ 15,002 | 56,566 | 53,830 | 61,581 |
| PIK dividends | 475 | 1,164 | $ 157 | ||||||||||||
| Fair value of the Company's investments on non-accrual status | $ 2,835 | $ 14,693 | $ 2,835 | $ 14,693 | |||||||||||