Annual report [Section 13 and 15(d), not S-K Item 405]

FINANCIAL HIGHLIGHTS (Details)

v3.25.4
FINANCIAL HIGHLIGHTS (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Investment Company, Financial Highlights [Roll Forward]                    
NAV as of the beginning of the period (in dollars per share) $ 15.53 $ 15.54 $ 15.22 $ 15.36 $ 14.56 $ 15.54 $ 15.92 $ 16.29 $ 16.29 $ 15.76
Net investment income (in dollars per share) 1.33 1.34 1.38 1.32 1.34 1.18 1.42 1.48 1.46 1.40
Net realized gain (loss) (in dollars per share) (0.20) 0.39 (0.85) (0.10) (0.07) (1.32) (0.47) (0.46) (0.06) (0.58)
Net unrealized appreciation (depreciation) (in dollars per share) 0.78 (0.38) 1.16 (0.04) 0.62 (0.08) 0.08 0 (0.04) 1.12
Income tax benefit (provision) on net realized gain (loss) and net unrealized appreciation (depreciation) (in dollars per share) 0 0.06 (0.04) (0.04) (0.05) (0.03) (0.02) 0 0 0
Net increase (decrease) in net assets resulting from operations (in dollars per share) 1.91 1.41 1.65 1.14 1.84 (0.25) 1.01 1.02 1.36 1.94
Dividends paid from net investment income (in dollars per share) (1.42) (1.10) (1.40) (1.29) (1.05) (0.70) (1.35) (1.40) (1.40) (1.40)
Distributions paid from capital gains (in dollars per share) (0.02) (0.35) 0 0 0 0 (0.05) 0 0 0
Distributions paid or accrued (in dollars per share) (1.44) (1.45) (1.40) (1.29) (1.05) (0.70) (1.40) (1.40) (1.40) (1.40)
Accretive effect of stock repurchases (repurchasing shares below NAV) (in dollars per share) 0.03 0.01 0.06 0 0          
Dilutive effect of stock offerings (issuing shares below NAV per share) (in dollars per share) (0.16) 0 0 0 0          
Other (in dollars per share) (0.02) 0.02 0.01 0.01 0.01 (0.03) 0.01 0.01 0.04 (0.01)
NAV as of the ending of the period (in dollars per share) 15.85 $ 15.53 $ 15.54 $ 15.22 $ 15.36 $ 14.56 $ 15.54 $ 15.92 $ 16.29 $ 16.29
Market value as of the end of the period (in dollars per share) $ 13.14                  
Shares outstanding as of the end of the period (in shares) 46,588,608 40,240,358 40,054,433 40,053,000 39,913,303 39,804,152 39,231,689 39,292,412 39,755,866 36,691,486
NAV as of the end of the period $ 738,659 $ 624,903 $ 622,307 $ 609,665 $ 613,170 $ 579,624 $ 609,305 $ 625,366 $ 647,789 $ 597,833
Average NAV 707,930 621,478 613,525 611,214 593,440 557,382 622,708 642,625 629,775 535,175
Average outstanding debt $ 550,058 $ 524,380 $ 487,271 $ 494,957 $ 321,973 $ 386,084 $ 474,000 $ 482,200 $ 427,200 $ 396,000
Ratios to average NAV:                    
Ratio of total expenses, including income tax expense, to average NAV (as a percent) 10.93% 12.65% 12.63% 8.60% 6.51% 7.38% 9.11% 9.11% 7.88% 7.56%
Ratio of operating expenses to average NAV (as a percent) 10.40% 12.47% 12.02% 8.33% 6.20% 7.16% 9.11% 8.95% 7.78% 7.50%
Ratio of operating expenses excluding interest expense, to average NAV (as a percent) 5.61% 6.19% 6.07% 4.33% 3.76% 4.07% 4.86% 5.09% 4.87% 4.69%
Ratio of operating expenses, excluding interest expense and incentive fees to average NAV (as a percent) 3.50% 4.18% 4.02% 3.98% 3.66% 4.07% 4.22% 4.57% 4.61% 4.68%
Ratio of net investment income to average NAV (as a percent) 8.72% 8.67% 9.04% 8.65% 8.99% 8.40% 8.84% 9.16% 9.01% 8.91%
Portfolio turnover ratio (as a percent) 22.56% 22.69% 21.82% 18.92% 35.39% 8.93% 33.30% 45.06% 50.66% 39.01%
Total investment return (as a percent) (6.74%)                  
Total return based on change in NAV (as a percent) 14.20% 9.77% 10.86% 7.43% 12.71% (1.80%) 6.41% 6.26% 8.59% 12.31%
Purchase of stock at the public offering price (in dollars per share) $ 15.53                  
Expense waivers   $ 9,500 $ 8,300 $ 4,500 $ 4,300 $ 3,600 $ 3,100 $ 6,000 $ 4,600 $ 4,000
Investment Company, Ratio To Average Net Assets Excluding Expense Waivers                    
Ratio of total expenses, including income tax expense, to average NAV (as a percent)   14.21% 13.98% 9.33% 7.24% 8.11% 9.84% 9.13% 7.89% 7.57%
Ratio of operating expenses to average NAV (as a percent)   14.03% 13.37% 9.06% 6.92% 7.89% 9.84% 8.97% 7.79% 7.51%
Ratio of operating expenses, excluding interest expense, to average NAV (as a percent)   7.73% 7.43% 5.07% 4.49% 4.80% 5.58% 5.10% 4.88% 4.69%
Ratio of operating expenses, excluding interest expense and incentive fees, to average NAV (as a percent)   0.0572 0.0538 0.0472 0.0439 0.0480 0.0495 0.0458 0.0461 0.0469
Ratio of net investment income to average NAV (as a percent)   7.17% 7.69% 7.90% 8.26% 7.67% 8.11% 8.25% 8.28% 8.48%