Financial Highlights - Schedule of Financial Highlights (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Per Share Data:
Net Asset Value Per Share, Beginning Balance			$ 20.04	$ 19.83
Net investment income after tax			1.21	1.09
Net realized and unrealized gains (losses) on investments, asset acquisition and forward contracts, net of taxes			0.1	(0.22)
Net increase (decrease) in net assets resulting from operations			1.31	0.87
Effects of First Eagle Alternative Capital BDC, Inc. acquisition (Note 13)				(0.3)
Distributions declared from net investment income			(1.04)	(0.82)
Effect of rounding			(0.01)
Total increase (decrease) in net assets			0.26	(0.25)
Net Asset Value Per Share, Ending Balance	$ 20.3	$ 19.58	$ 20.3	$ 19.58
Shares outstanding, end of period	37,061,547	37,061,547	37,061,547	37,061,547
Market value, end of period	$ 18.78	$ 15.14	$ 18.78	$ 15.14
Weighted average shares outstanding (basic):	37,061,547	37,061,547	37,061,547	34,776,074
Weighted average shares outstanding (diluted):	37,061,547	37,061,547	37,061,547	34,776,074
Total return based on market value			14.46%	25.34%
Total return based on net asset value			6.49%	2.87%
Ratio/Supplemental Data:
Net assets, end of period	$ 752,440	$ 725,805	$ 752,440	$ 725,805
Ratio of total net expenses to average net assets			14.58%	14.11%
Ratio of net expenses (without incentive fees and interest and other debt expenses) to average net assets			3.56%	3.66%
Ratio of net investment income before taxes to average net assets			12.30%	11.36%
Ratio of interest and credit facility expenses to average net assets			8.47%	8.13%
Ratio of net incentive fees to average net assets			2.55%	2.32%
Portfolio turnover			10.81%	4.61%
Asset coverage ratio			184.00%	183.00%