Consolidated Statements of Changes in Net Assets - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Increase (Decrease) in Stockholders' Equity
Beginning Balance	$ 347,425	$ 347,919	$ 349,751	$ 319,621	$ 314,349	$ 312,897	$ 349,751	$ 312,897
Beginning Balance (in shares)			23,162,667				23,162,667
Stock issued in connection with at-the-market offering		(72)	$ 197	$ 1,438	1,894	590
Stock issued in connection with at-the-market offering (in shares)				214,278			80,421	390,842
Stock issued in connection with dividend reinvestment plan		480	498	$ 1,823	225
Net increase in net assets resulting from operations:
Net investment income after excise tax	9,768	7,877	8,539	7,639	6,100	7,600
Net realized gains (losses) on investments	230	2,342	(18,465)	(96)	(563)	8,161
Net change in unrealized appreciation (depreciation) on investments	(6,153)	(2,870)	15,633	732	4,974	(7,592)
Distributions declared	(8,251)	(8,251)	(8,234)	(7,433)	(7,358)	(7,307)
Ending Balance	$ 343,019	347,425	347,919	323,724	319,621	314,349	$ 343,019	$ 323,724
Ending Balance (in shares)	23,243,088						23,243,088
Common Stock
Increase (Decrease) in Stockholders' Equity
Beginning Balance	$ 23	$ 23	$ 23	$ 21	$ 21	$ 21	$ 23	$ 21
Beginning Balance (in shares)	23,243,088	23,211,413	23,162,667	20,722,596	20,583,835	20,546,032	23,162,667	20,546,032
Stock issued in connection with at-the-market offering (in shares)			16,678	94,897	124,252	37,803
Stock issued in connection with dividend reinvestment plan (in shares)		31,675	32,068	119,381	14,509
Net increase in net assets resulting from operations:
Ending Balance	$ 23	$ 23	$ 23	$ 21	$ 21	$ 21	$ 23	$ 21
Ending Balance (in shares)	23,243,088	23,243,088	23,211,413	20,936,874	20,722,596	20,583,835	23,243,088	20,936,874
Paid-in Capital in Excess of Par
Increase (Decrease) in Stockholders' Equity
Beginning Balance	$ 340,264	$ 339,856	$ 339,161	$ 302,711	$ 300,592	$ 300,002	$ 339,161	$ 300,002
Stock issued in connection with at-the-market offering		(72)	197	1,438	1,894	590
Stock issued in connection with dividend reinvestment plan		480	498	1,823	225
Net increase in net assets resulting from operations:
Ending Balance	340,264	340,264	339,856	305,972	302,711	300,592	340,264	305,972
Accumulated Earnings (Loss)
Increase (Decrease) in Stockholders' Equity
Beginning Balance	7,138	8,040	10,567	16,889	13,736	12,874	10,567	12,874
Net increase in net assets resulting from operations:
Net investment income after excise tax	9,768	7,877	8,539	7,639	6,100	7,600
Net realized gains (losses) on investments	230	2,342	(18,465)	(96)	(563)	8,161
Net change in unrealized appreciation (depreciation) on investments	(6,153)	(2,870)	15,633	732	4,974	(7,592)
Distributions declared	(8,251)	(8,251)	(8,234)	(7,433)	(7,358)	(7,307)
Ending Balance	$ 2,732	$ 7,138	$ 8,040	$ 17,731	$ 16,889	$ 13,736	$ 2,732	$ 17,731