Annual report pursuant to Section 13 and 15(d)

FINANCIAL HIGHLIGHTS (Details)

v3.24.0.1
FINANCIAL HIGHLIGHTS (Details) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Investment Company, Financial Highlights [Roll Forward]                    
NAV at the beginning of the period (in dollars per share) $ 26.86 $ 25.29 $ 22.35 $ 23.91 $ 24.09 $ 23.53 $ 22.10 $ 21.24 $ 20.85 $ 19.89
Net investment income (in dollars per share) 4.14 3.29 2.65 2.10 2.50 2.60 2.39 2.23 2.18 2.20
Net realized gain (loss) (in dollars per share) (1.47) (0.07) 0.66 (1.77) (0.33) (0.03) 0.19 0.56 (0.43) 0.53
Net unrealized appreciation (depreciation) (in dollars per share) 2.84 0.33 1.97 (0.09) (0.09) 0.32 0.86 (0.14) 0.20 (0.27)
Income tax benefit (provision) (in dollars per share) (0.28) (0.31) (0.48) 0.21 (0.02) (0.09) (0.43) 0.02 0.18 (0.15)
Net increase in net assets resulting from operations (in dollars per share) 5.23 3.24 4.80 0.45 2.06 2.80 3.01 2.67 2.13 2.31
Dividends paid from net investment income (in dollars per share) (3.70) (2.95) (2.58) (2.46) (2.91) (2.69) (2.47) (1.99) (2.49) (2.17)
Distributions from capital gains (in dollars per share)           (0.16) (0.32) (0.74) (0.16) (0.38)
Dividends paid (in dollars per share) (3.70) (2.95) (2.58) (2.46) (2.91) (2.85) (2.79) (2.73) (2.65) (2.55)
Impact of the net change in monthly dividends declared prior to the end of the period and paid in the subsequent period (in dollars per share) (0.01) (0.01) (0.01) 0 (0.01) (0.01) (0.01) (0.01) (0.01) (0.01)
Accretive effect of stock offerings (issuing shares above NAV per share) (in dollars per share) 0.67 1.17 0.58 0.41 0.55 0.47 1.07 0.76 0.74 1.07
Accretive effect of DRIP issuance (issuing shares above NAV per share) (in dollars per share) 0.10 0.09 0.09 0.08 0.12 0.09 0.06 0.08 0.12 0.12
Other (in dollars per share) 0.05 0.03 0.06 (0.04) 0.01 0.06 0.09 0.09 0.06 0.02
NAV at the end of the period (in dollars per share) 29.20 26.86 25.29 22.35 23.91 24.09 23.53 22.10 21.24 20.85
Market value at the end of the period (in dollars per share) $ 43.23 $ 36.95 $ 44.86 $ 32.26 $ 43.11 $ 33.81 $ 39.73 $ 36.77 $ 29.08 $ 29.24
Shares outstanding at the end of the period (in shares) 84,833,002 78,506,816 70,737,021 67,762,032 64,252,937 61,264,861 58,660,680 54,354,857 50,413,744 45,079,150
NAV at end of period $ 2,477,399 $ 2,108,586 $ 1,788,846 $ 1,514,767 $ 1,536,390 $ 1,476,049 $ 1,380,368 $ 1,201,481 $ 1,070,894 $ 939,982
Average NAV 2,276,932 1,923,134 1,626,585 1,436,291 1,517,615 1,441,163 1,287,639 1,118,567 1,053,313 885,568
Average outstanding debt $ 1,951,923 $ 1,882,462 $ 1,417,831 $ 1,152,108 $ 1,055,800 $ 947,694 $ 843,993 $ 801,048 $ 759,396 $ 575,524
Investment Company, Ratio To Average Net Assets [Abstract]                    
Ratio of total expenses, including income tax expense, to average NAV (as a percent) 8.08% 8.05% 8.56% 4.95% 5.75% 5.75% 7.37% 5.48% 4.63% 5.82%
Ratio of operating expenses to average NAV (as a percent) 7.09% 6.84% 6.54% 5.89% 5.67% 5.32% 5.47% 5.59% 5.45% 5.11%
Ratio of operating expenses, excluding interest expense, to average NAV (as a percent) 2.58% 2.77% 2.92% 2.44% 2.36% 2.30% 2.63% 2.58% 2.41% 2.44%
Ratio of net investment income to average NAV (as a percent) 14.89% 12.76% 11.23% 9.60% 10.37% 10.87% 10.51% 10.35% 10.15% 10.79%
Portfolio turnover ratio (as a percent) 19.24% 16.79% 29.81% 18.00% 18.86% 29.13% 38.18% 24.63% 25.37% 35.71%
Total investment return (as a percent) 28.23% (11.18%) 48.24% (19.11%) 36.86% (8.25%) 16.02% 37.36% 8.49% (3.09%)
Total return based on change in NAV (as a percent) 20.32% 13.51% 21.84% 1.91% 8.78% 12.19% 14.20% 12.97% 11.11% 12.71%
Related Party | External Investment Manager                    
Investment Company, Ratio To Average Net Assets [Abstract]                    
Total expenses $ 22,100 $ 13,000 $ (10,300) $ 7,400 $ 6,700 $ 6,800 $ 6,400 $ 5,100 $ 4,300 $ 2,000