Investments - Summary of Company's Portfolio Investment by Industry at Cost and Fair Value and as Percentage of Total Portfolio (Details) - USD ($) $ in Thousands		Mar. 31, 2024	Dec. 31, 2023
Schedule Of Investments [Line Items]
Cost		$ 1,419,998	$ 1,319,316
Cost, Percentage		100.00%	100.00%
Fair Value		$ 1,363,862	$ 1,275,180
Fair Value, Percentage		100.00%	100.00%
Finance and Insurance
Schedule Of Investments [Line Items]
Cost		$ 190,781	$ 139,399
Cost, Percentage		13.30%	10.60%
Fair Value		$ 189,158	$ 133,344
Fair Value, Percentage		13.90%	10.50%
Green Technology
Schedule Of Investments [Line Items]
Cost		$ 149,648	$ 138,510
Cost, Percentage		10.50%	10.50%
Fair Value		$ 154,883	$ 143,279
Fair Value, Percentage		11.40%	11.20%
Space Technology
Schedule Of Investments [Line Items]
Cost		$ 124,130	$ 185,384
Cost, Percentage		8.70%	14.10%
Fair Value		$ 124,504	$ 186,335
Fair Value, Percentage		9.10%	14.60%
Consumer Products & Services
Schedule Of Investments [Line Items]
Cost		$ 92,354	$ 85,683
Cost, Percentage		6.50%	6.50%
Fair Value		$ 91,657	$ 83,722
Fair Value, Percentage		6.70%	6.60%
Real Estate Technology
Schedule Of Investments [Line Items]
Cost		$ 93,027	$ 94,878
Cost, Percentage		6.60%	7.20%
Fair Value		$ 89,264	$ 91,344
Fair Value, Percentage		6.50%	7.20%
Healthcare Technology
Schedule Of Investments [Line Items]
Cost		$ 87,652	$ 89,038
Cost, Percentage		6.20%	6.80%
Fair Value		$ 83,697	$ 84,917
Fair Value, Percentage		6.10%	6.60%
Food and Agriculture Technologies
Schedule Of Investments [Line Items]
Cost		$ 84,125	$ 90,967
Cost, Percentage		5.90%	6.90%
Fair Value		$ 79,608	$ 88,707
Fair Value, Percentage		5.80%	7.00%
Medical Devices
Schedule Of Investments [Line Items]
Cost		$ 70,431	$ 68,717
Cost, Percentage		5.00%	5.20%
Fair Value		$ 71,809	$ 70,320
Fair Value, Percentage		5.30%	5.50%
Artificial Intelligence & Automation
Schedule Of Investments [Line Items]
Cost		$ 64,679	$ 34,732
Cost, Percentage		4.60%	2.60%
Fair Value		$ 63,905	$ 34,435
Fair Value, Percentage		4.70%	2.70%
Biotechnology
Schedule Of Investments [Line Items]
Cost		$ 56,665	$ 56,173
Cost, Percentage		4.00%	4.30%
Fair Value		$ 57,399	$ 55,810
Fair Value, Percentage		4.20%	4.40%
SaaS
Schedule Of Investments [Line Items]
Cost		$ 48,560	$ 34,257
Cost, Percentage		3.40%	2.60%
Fair Value		$ 49,850	$ 34,440
Fair Value, Percentage		3.70%	2.70%
Marketing, Media, and Entertainment
Schedule Of Investments [Line Items]
Cost		$ 47,688	$ 49,145
Cost, Percentage		3.40%	3.70%
Fair Value		$ 46,526	$ 47,526
Fair Value, Percentage		3.40%	3.70%
Diagnostics & Tools
Schedule Of Investments [Line Items]
Cost		$ 42,081
Cost, Percentage		3.00%
Fair Value		$ 42,081
Fair Value, Percentage		3.10%
Education Technology
Schedule Of Investments [Line Items]
Cost		$ 42,927	$ 18,975
Cost, Percentage		3.00%	1.40%
Fair Value		$ 39,964	$ 15,285
Fair Value, Percentage		2.90%	1.20%
Connectivity
Schedule Of Investments [Line Items]
Cost		$ 36,161	$ 36,191
Cost, Percentage		2.50%	2.70%
Fair Value		$ 34,794	$ 34,219
Fair Value, Percentage		2.60%	2.70%
Human Resource Technology
Schedule Of Investments [Line Items]
Cost		$ 31,246	$ 31,142
Cost, Percentage		2.20%	2.40%
Fair Value		$ 30,708	$ 30,595
Fair Value, Percentage		2.30%	2.40%
Transportation Technology
Schedule Of Investments [Line Items]
Cost		$ 43,633	$ 45,024
Cost, Percentage		3.10%	3.40%
Fair Value		$ 28,955	$ 39,532
Fair Value, Percentage		2.10%	3.10%
Supply Chain Technology
Schedule Of Investments [Line Items]
Cost		$ 31,426	$ 30,414
Cost, Percentage		2.20%	2.30%
Fair Value		$ 25,368	$ 24,556
Fair Value, Percentage		1.90%	1.90%
Digital Assets Technology and Services
Schedule Of Investments [Line Items]
Cost		$ 26,294	$ 33,545
Cost, Percentage		1.90%	2.50%
Fair Value		$ 20,950	$ 35,553
Fair Value, Percentage		1.50%	2.80%
Industrials
Schedule Of Investments [Line Items]
Cost		$ 18,102	$ 21,995
Cost, Percentage		1.30%	1.70%
Fair Value		$ 19,181	$ 23,113
Fair Value, Percentage		1.40%	1.80%
Multi-Sector Holdings
Schedule Of Investments [Line Items]
Cost	[1]	$ 13,420	$ 11,006
Cost, Percentage	[1]	0.90%	0.80%
Fair Value	[1]	$ 14,003	$ 11,335
Fair Value, Percentage	[1]	1.00%	0.90%
Construction Technology
Schedule Of Investments [Line Items]
Cost		$ 24,968	$ 24,141
Cost, Percentage		1.80%	1.80%
Fair Value		$ 5,598	$ 6,813
Fair Value, Percentage		0.40%	0.50%

[1] Multi-Sector Holdings consists of the Company's investment in Senior Credit Corp 2022 LLC, a joint venture between the Company and the JV Partner. This entity invests in secured loans and equipment financings to growth-stage companies that have been originated by the Company. The portfolio companies held by the JV represent a diverse set of industry classifications, which are similar to those in which the Company invests directly. See “Note 1 – Organization and Basis of Presentation” for further discussion.