Investments - Summary of Investment Portfolio (Detail) - USD ($) $ in Thousands	Sep. 30, 2025		Dec. 31, 2024
Amortized Cost
Investment	$ 1,012,284	[1],[2],[3]	$ 892,940	[4],[5],[6]
Fair Value
Fair Value	$ 1,352,090	[1],[2],[3]	$ 1,140,859	[4],[5],[6]
Fair Value Percentage of Investment Portfolio	100.00%		100.00%
Fair Value Percentage of Net Assets	98.60%	[1],[2],[3]	92.70%	[4],[5],[6]
Milton Industries Inc
Fair Value
Fair Value	$ 2,300
Total Senior Secured Notes
Amortized Cost
Investment	319,611	[1],[2],[3]	$ 292,284	[4],[5],[6]
Fair Value
Fair Value	319,793	[1],[2],[3]	292,284	[4],[5],[6]
First lien
Amortized Cost
Investment	66,990	[1],[2],[3]	66,990	[4],[5],[6]
Fair Value
Fair Value	$ 66,990	[1],[2],[3]	$ 66,990	[4],[5],[6]
Fair Value Percentage of Net Assets	4.80%	[1],[2],[3]	5.40%	[4],[5],[6]
Secured
Amortized Cost
Investment	$ 171,389	[1],[2],[3]	$ 148,576	[4],[5],[6]
Fair Value
Fair Value	$ 171,389	[1],[2],[3]	$ 148,576	[4],[5],[6]
Fair Value Percentage of Net Assets	12.50%	[1],[2],[3]	12.10%	[4],[5],[6]
Second lien
Amortized Cost
Investment	$ 62,402	[1],[2],[3]	$ 76,718	[4],[5],[6]
Fair Value
Fair Value	$ 62,402	[1],[2],[3]	$ 76,718	[4],[5],[6]
Fair Value Percentage of Net Assets	4.60%	[1],[2],[3]	6.20%	[4],[5],[6]
Total Senior Secured Notes
Amortized Cost
Senior secured debt	$ 319,611		$ 292,284
Fair Value
Senior secured debt	$ 319,793		$ 292,284
Fair Value Percentage of Investment Portfolio	23.70%		25.60%
Fair Value Percentage of Net Assets	23.30%		23.70%
First lien
Amortized Cost
Senior secured debt	$ 66,990		$ 66,990
Fair Value
Senior secured debt	$ 66,990		$ 66,990
Fair Value Percentage of Investment Portfolio	5.00%		5.90%
Fair Value Percentage of Net Assets	4.80%		5.40%
Secured
Amortized Cost
Senior secured debt	$ 171,389		$ 148,576
Fair Value
Senior secured debt	$ 171,389		$ 148,576
Fair Value Percentage of Investment Portfolio	12.70%		13.00%
Fair Value Percentage of Net Assets	12.50%		12.10%
Second lien
Amortized Cost
Senior secured debt	$ 62,402		$ 76,718
Fair Value
Senior secured debt	$ 62,402		$ 76,718
Fair Value Percentage of Investment Portfolio	4.60%		6.70%
Fair Value Percentage of Net Assets	4.60%		6.20%
PIK notes
Amortized Cost
Senior secured debt	$ 18,830
Fair Value
Senior secured debt	$ 19,012
Fair Value Percentage of Investment Portfolio	1.40%
Fair Value Percentage of Net Assets	1.40%
Equity
Amortized Cost
Equity	$ 692,673		$ 600,656
Fair Value
Equity	$ 1,032,297		$ 848,575
Fair Value Percentage of Investment Portfolio	76.30%		74.40%
Fair Value Percentage of Net Assets	75.30%		69.00%
Preferred
Amortized Cost
Equity	$ 74,812		$ 62,070
Fair Value
Equity	$ 78,416		$ 61,155
Fair Value Percentage of Investment Portfolio	5.80%		5.40%
Fair Value Percentage of Net Assets	5.70%		5.00%
Common
Amortized Cost
Equity	$ 617,861		$ 538,586
Fair Value
Equity	$ 953,881		$ 787,420
Fair Value Percentage of Investment Portfolio	70.50%		69.00%
Fair Value Percentage of Net Assets	69.60%		64.00%

[1] All investments are US based unless otherwise noted.

[2] Percentages represent fair value as a percentage of net assets for each investment category.

[3] Security may be an obligation of one or more entities affiliated with the named company.

[4] All investments are US based unless otherwise noted.

[5] Percentages represent fair value as a percentage of net assets for each investment category.

[6] Security may be an obligation of one or more entities affiliated with the named company.