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
Investment Company, Financial Highlights [Roll Forward]
Net asset value per share at beginning of year (in usd per share)	$ 12.85	$ 12.09	$ 13.47	$ 15.18	$ 11.85
Net investment income (in usd per share)	0.92	1.25	1.50	1.37	1.00
Net realized loss on investments, net of taxes (in usd per share)	(0.91)	(1.28)	(0.85)	(0.13)	(1.54)
Net unrealized appreciation (depreciation) on investments, net of deferred taxes (in usd per share)	(2.44)	2.15	(0.67)	(1.79)	5.12
Loss on extinguishment of debt (in usd per share)	(0.04)	0	(0.02)	(0.01)	(0.34)
Total from operations (in usd per share)	(2.47)	2.12	(0.04)	(0.56)	4.24
Distributions declared per common share (in usd per share)	(0.39)	(1.36)	(1.34)	(1.16)	(0.91)
Distributions from tax return of capital (in usd per share)	(0.80)	0	0	0	0
Issuance/repurchase of common stock (in usd per share)	0	0	0	0.01	0
Net asset value per share at end of year (in usd per share)	9.19	12.85	12.09	13.47	15.18
Per share market value, end of period (in usd per share)	$ 4.76	$ 8.07	$ 11.70	$ 10.15	$ 10.90
Total return based on market value	(31.30%)	(19.70%)	30.20%	4.40%	66.80%
Total return based on net asset value	(16.70%)	23.70%	1.40%	(0.60%)	40.20%
Shares outstanding at end of period (in shares)	13,398,078	13,398,078	13,398,078	13,398,078	13,422,413
Basic weighted-average shares outstanding (in shares)	13,398,078	13,398,078	13,398,078	13,417,410	13,413,861
Diluted weighted-average shares outstanding (in shares)	13,398,078	13,398,078	13,398,078	13,417,410	13,413,861
Ratio/Supplemental Data (in thousands except ratios)
Average net asset value	$ 147,661	$ 157,621	$ 173,265	$ 194,068	$ 178,628
Net asset value at end of year	123,188	172,225	162,004	180,423	203,744
Net investment income	$ 12,384	$ 16,712	$ 20,160	$ 18,352	$ 13,450
Ratio of total expenses to average net assets	19.20%	19.80%	21.20%	15.70%	19.20%
Ratio of total expenses and loss on extinguishment of debt to average net assets	19.50%	19.80%	21.40%	15.70%	21.80%
Ratio of net investment income to average net assets	8.40%	10.60%	11.60%	9.50%	7.50%
Ratio of loss on extinguishment of debt to average net assets	0.30%	0.00%	0.10%	0.10%	2.60%
Portfolio turnover	13.20%	23.10%	8.80%	28.00%	54.90%