Financial Highlights - Financial highlights (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Per share data:
Net asset value at beginning of period	$ 10.39	$ 11.51
Net investment income	0.83	0.77
Net gain (loss)	(0.89)	(1.10)
Net increase (decrease) in net assets resulting from operations	(0.06)	(0.33)
Stockholder distributions - income	(0.75)	(0.75)
Net asset value at end of period	$ 9.58	$ 10.43
Net assets at end of period	$ 207,555	$ 225,956
Shares outstanding at end of period	21,666,340	21,666,340
Per share market value at end of period	$ 7.45	$ 7.24
Total return based on market value	(4.08%)	(30.10%)
Total return based on average net asset value	(0.56%)	(3.05%)
Ratio/Supplemental data:
Ratio of net investment income to average net assets	11.76%	9.67%
Ratio of total expenses, net of base management fee and incentive fee waivers, to average net assets	18.28%	13.58%
Portfolio turnover	9.91%	17.53%