INVESTMENTS - Schedule of Industry Composition of Investment at Fair Value (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2026	Dec. 31, 2025
Schedule of Investments [Line Items]
Fair Value	$ 2,509,771	$ 2,398,524
Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	1,231,039	1,241,387
Jocassee Partners LLC \| Investment, Excluding Short Term Investment, with Previous Commitment to Provide Financing
Schedule of Investments [Line Items]
Fair Value	$ 1,157,364	1,223,606
Sierra JV
Schedule of Investments [Line Items]
Fair Value		$ 2,701
Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	100.00%	100.00%
Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Sierra JV
Schedule of Investments [Line Items]
Percentage of Total Portfolio		100.00%
Aerospace & Defense \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 51,551	$ 66,828
Aerospace & Defense \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	5.00%	6.00%
Automotive \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 14,160	$ 12,505
Automotive \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	1.00%	1.00%
Banking, Finance, Insurance, & Real Estate \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 111,634	$ 130,393
Banking, Finance, Insurance, & Real Estate \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	10.00%	11.00%
Beverage, Food, & Tobacco \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 15,865	$ 32,102
Beverage, Food, & Tobacco \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	1.00%	3.00%
Capital Equipment \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 42,027	$ 40,454
Capital Equipment \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	4.00%	3.00%
Chemicals, Plastics, & Rubber \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 22,004	$ 26,223
Chemicals, Plastics, & Rubber \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	2.00%	2.00%
Construction & Building \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 36,456	$ 28,031
Construction & Building \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	3.00%	2.00%
Consumer goods: Durable \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 16,124	$ 24,400
Consumer goods: Durable \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	1.00%	2.00%
Consumer goods: Non-durable \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 23,560	$ 28,825
Consumer goods: Non-durable \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	2.00%	2.00%
Containers, Packaging, & Glass \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 35,947	$ 32,380
Containers, Packaging, & Glass \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	3.00%	3.00%
Energy: Electricity \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 10,394	$ 8,968
Energy: Electricity \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	1.00%	1.00%
Energy: Oil & Gas \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 16,930	$ 11,493
Energy: Oil & Gas \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	1.00%	1.00%
Environmental Industries \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 14,785	$ 15,460
Environmental Industries \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	1.00%	1.00%
Forest Products & Paper \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 2,712	$ 2,521
Forest Products & Paper \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	0.00%	0.00%
Healthcare & Pharmaceuticals \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 128,002	$ 136,378
Healthcare & Pharmaceuticals \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	11.00%	11.00%
High Tech Industries \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 114,029	$ 118,164
High Tech Industries \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	10.00%	10.00%
Hotel, Gaming, & Leisure \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 36,260	$ 28,795
Hotel, Gaming, & Leisure \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	3.00%	2.00%
Investment Funds & Vehicles \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 3,101	$ 10,274
Investment Funds & Vehicles \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	0.00%	1.00%
Media: Advertising, Printing, & Publishing \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 19,584	$ 14,565
Media: Advertising, Printing, & Publishing \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	2.00%	1.00%
Media: Broadcasting & Subscription \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 15,780	$ 13,702
Media: Broadcasting & Subscription \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	1.00%	1.00%
Media: Diversified & Production \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 41,050	$ 48,553
Media: Diversified & Production \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	4.00%	4.00%
Metals & Mining \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 7,023	$ 5,250
Metals & Mining \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	1.00%	0.00%
Retail \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 6,238	$ 9,728
Retail \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	1.00%	1.00%
Services: Business \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 209,362	$ 219,055
Services: Business \| Sierra JV
Schedule of Investments [Line Items]
Fair Value		$ 2,701
Services: Business \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	18.00%	18.00%
Services: Business \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Sierra JV
Schedule of Investments [Line Items]
Percentage of Total Portfolio		100.00%
Services: Consumer \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 69,447	$ 71,818
Services: Consumer \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	6.00%	6.00%
Telecommunications \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 19,747	$ 20,859
Telecommunications \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	2.00%	2.00%
Transportation: Cargo \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 35,937	$ 38,392
Transportation: Cargo \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	3.00%	3.00%
Transportation: Consumer \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 11,909	$ 8,312
Transportation: Consumer \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	1.00%	1.00%
Utilities: Electric \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 21,348	$ 17,437
Utilities: Electric \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	2.00%	1.00%
Utilities: Oil & Gas \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Fair Value	$ 4,398	$ 1,741
Utilities: Oil & Gas \| Percentage of Total Portfolio, at Fair Value \| Industry Concentration Risk \| Jocassee Partners LLC
Schedule of Investments [Line Items]
Percentage of Total Portfolio	0.00%	0.00%