Commitments and Contingencies - Schedule of Unfunded Commitments to Extend Financing (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	$ 235,820	$ 201,520
3PL Central LLC (dba Extensiv) | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing		11,500
Betterment Holdings, Inc. | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	5,000	5,000
Blueshift Labs, Inc. | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	14,500	14,500
Bombora, Inc. | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	2,000	2,000
Brivo, Inc | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	6,000	6,000
CarNow, Inc. | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	12,000
EBR Systems, Inc. | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	10,000	10,000
Interactions Corporation | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	10,000	10,000
Madison Reed, Inc. | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing		1,200
Linxup, LLC | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	7,500	7,500
Moximed, Inc. | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	15,000	15,000
Nalu Medical, Inc. | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	15,000	15,000
Route 92 Medical, Inc. | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	20,000	20,000
Runway-Cadma I LLC | Joint Venture
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	35,000
SetPoint Medical Corporation | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	40,000	40,000
Skillshare, Inc. | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	10,000	10,000
Snagajob.com, Inc. | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	6,785	6,785
Snagajob.com, Inc. | Convertible Note
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	2,035	2,035
Synack, Inc. | Senior Secured Term Loan
Schedule Of Investments [Line Items]
Total unused commitments to extend financing	$ 25,000	$ 25,000