Quarterly report pursuant to Section 13 or 15(d)

FINANCIAL HIGHLIGHTS (Details)

v3.22.2.2
FINANCIAL HIGHLIGHTS (Details) - USD ($)
$ / shares in Units, $ in Thousands
 9 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Jun. 30, 2022
Mar. 31, 2022
Dec. 31, 2021
Jun. 30, 2021
Mar. 31, 2021
Dec. 31, 2020
Investment Company, Financial Highlights [Roll Forward]                
NAV at the beginning of the period (in dollars per share) $ 25.29 $ 22.35            
Net investment income (in dollars per share) 2.31 1.92            
Net realized gain (loss) (in dollars per share) 0.05 0.15            
Net unrealized appreciation (depreciation) (in dollars per share) (0.28) 1.71            
Income tax provision (in dollars per share) (0.24) (0.33)            
Net increase in net assets resulting from operations (in dollars per share) 1.84 3.45            
Dividends paid from net investment income (in dollars per share) (2.19) (1.85)            
Distributions from capital gains (in dollars per share) 0 0            
Dividends paid (in dollars per share) (2.19) (1.85)            
Accretive effect of stock offerings (issuing shares above NAV per share) (in dollars per share) 0.98 0.26            
Accretive effect of DRIP issuance (issuing shares above NAV per share) (in dollars per share) 0.08 0.06            
Other (in dollars per share) (0.06) 0.01            
NAV at the end of the period (in dollars per share) 25.94 24.27            
Market value at the end of the period (in dollars per share) $ 33.64 $ 41.10            
Shares outstanding at the end of the period (in shares) 76,308,830 69,408,645            
NAV at end of period $ 1,979,420 $ 1,684,307 $ 1,865,163 $ 1,873,654 $ 1,788,846 $ 1,604,841 $ 1,540,164 $ 1,514,767
Average NAV 1,876,771 1,586,020            
Average outstanding debt $ 1,880,100 $ 1,264,680            
Investment Company, Ratio To Average Net Assets [Abstract]                
Ratio of total expenses, including income tax expense, to average NAV 5.92% 6.19%            
Ratio of operating expenses to average NAV 4.99% 4.76%            
Ratio of operating expenses, excluding interest expense, to average NAV 2.05% 2.05%            
Ratio of net investment income to average NAV 9.03% 8.29%            
Portfolio turnover ratio 12.46% 20.69%            
Total investment return (20.81%) 33.57%            
Total return based on change in NAV 7.56% 15.61%            
Affiliated Entity | External Investment Manager                
Investment Company, Ratio To Average Net Assets [Abstract]                
Total expenses $ 9,600 $ 7,700