CONSOLIDATED SCHEDULE OF INVESTMENTS IN AND ADVANCES TO AFFILIATES - Schedule of Investment Gain/(Loss) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income	$ 149,114	$ 137,459	$ 290,650	$ 256,970
Investments, fair value, beginning balance			4,466,647
Net Change in Unrealized Appreciation (Depreciation)	29,566	47,790	(15,439)	22,225
Investments, fair value, ending balance	4,583,870		4,583,870
Control investments
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income			6,929	7,085
Realized Gain (Loss)	0	0	0	0
Investments, fair value, beginning balance			115,051	113,179
Gross Additions			8,068	13,176
Gross Reductions			(600)	(12,600)
Net Change in Unrealized Appreciation (Depreciation)	(447)	(836)	(1,986)	1,141
Investments, fair value, ending balance	120,533	114,896	120,533	114,896
Control investments \| Majority Owned Control Investments
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income			6,588	6,743
Realized Gain (Loss)			0	0
Investments, fair value, beginning balance			105,710	101,522
Gross Additions			8,068	13,176
Gross Reductions			(600)	(12,600)
Net Change in Unrealized Appreciation (Depreciation)			(1,677)	2,780
Investments, fair value, ending balance	111,501	104,878	111,501	104,878
Control investments \| Other Control Investments
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income			341	342
Realized Gain (Loss)			0	0
Investments, fair value, beginning balance			9,341	11,657
Gross Additions			0	0
Gross Reductions			0	0
Net Change in Unrealized Appreciation (Depreciation)			(309)	(1,639)
Investments, fair value, ending balance	9,032	10,018	9,032	10,018
Coronado Aesthetics, LLC \| Control investments
Schedule Of Investments [Line Items]
Realized Gain (Loss)	0	0	0	0
Net Change in Unrealized Appreciation (Depreciation)	64	267	4	244
Investments, fair value, ending balance	222	313	222	313
Gibraltar Business Capital, LLC \| Control investments
Schedule Of Investments [Line Items]
Realized Gain (Loss)	0	0	0	0
Net Change in Unrealized Appreciation (Depreciation)	845	1,444	1,058	504
Investments, fair value, ending balance	62,744	60,343	62,744	60,343
Hercules Adviser LLC \| Control investments
Schedule Of Investments [Line Items]
Realized Gain (Loss)	0	0	0	0
Net Change in Unrealized Appreciation (Depreciation)	(602)	(795)	(2,739)	2,032
Investments, fair value, ending balance	48,535	44,222	48,535	44,222
Tectura Corporation \| Control investments
Schedule Of Investments [Line Items]
Realized Gain (Loss)	0	0	0	0
Net Change in Unrealized Appreciation (Depreciation)	(754)	(1,752)	(309)	(1,639)
Investments, fair value, ending balance	9,032	10,018	9,032	10,018
Preferred Stock \| Coronado Aesthetics, LLC \| Control investments \| Majority Owned Control Investments
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income			0	0
Realized Gain (Loss)			0	0
Investments, fair value, beginning balance			218	69
Gross Additions			0	0
Gross Reductions			0	0
Net Change in Unrealized Appreciation (Depreciation)			4	243
Investments, fair value, ending balance	222	312	222	312
Preferred Stock \| Tectura Corporation \| Control investments \| Other Control Investments
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income			0	0
Realized Gain (Loss)			0	0
Investments, fair value, beginning balance			1,250	3,623
Gross Additions			0	0
Gross Reductions			0	0
Net Change in Unrealized Appreciation (Depreciation)			(468)	(1,581)
Investments, fair value, ending balance	782	2,042	782	2,042
Common Stock \| Coronado Aesthetics, LLC \| Control investments \| Majority Owned Control Investments
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income			0	0
Realized Gain (Loss)			0	0
Investments, fair value, beginning balance			0	0
Gross Additions			0	0
Gross Reductions			0	0
Net Change in Unrealized Appreciation (Depreciation)			0	1
Investments, fair value, ending balance	0	1	0	1
Common Stock \| Tectura Corporation \| Control investments \| Other Control Investments
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income			0	0
Realized Gain (Loss)			0	0
Investments, fair value, beginning balance			0	7
Gross Additions			0	0
Gross Reductions			0	0
Net Change in Unrealized Appreciation (Depreciation)			0	(7)
Investments, fair value, ending balance	0	0	0	0
Unsecured Debt \| Gibraltar Business Capital, LLC \| Control investments \| Majority Owned Control Investments
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income			2,335	2,743
Realized Gain (Loss)			0	0
Investments, fair value, beginning balance			38,255	36,212
Gross Additions			68	1,176
Gross Reductions			0	0
Net Change in Unrealized Appreciation (Depreciation)			0	0
Investments, fair value, ending balance	38,323	37,388	38,323	37,388
Unsecured Debt \| Hercules Adviser LLC \| Control investments \| Majority Owned Control Investments
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income			4,253	4,000
Realized Gain (Loss)			0	0
Investments, fair value, beginning balance			0	12,000
Gross Additions			8,000	0
Gross Reductions			0	(12,000)
Net Change in Unrealized Appreciation (Depreciation)			0	0
Investments, fair value, ending balance	8,000	0	8,000	0
Member Units \| Gibraltar Business Capital, LLC \| Control investments \| Majority Owned Control Investments
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income			0	0
Realized Gain (Loss)			0	0
Investments, fair value, beginning balance			23,963	23,051
Gross Additions			0	0
Gross Reductions			(600)	(600)
Net Change in Unrealized Appreciation (Depreciation)			1,058	504
Investments, fair value, ending balance	24,421	22,955	24,421	22,955
Member Units \| Hercules Adviser LLC \| Control investments \| Majority Owned Control Investments
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income			0	0
Realized Gain (Loss)			0	0
Investments, fair value, beginning balance			43,274	30,190
Gross Additions			0	12,000
Gross Reductions			0	0
Net Change in Unrealized Appreciation (Depreciation)			(2,739)	2,032
Investments, fair value, ending balance	40,535	44,222	40,535	44,222
Senior Secured Debt \| Tectura Corporation \| Control investments \| Other Control Investments
Schedule Of Investments [Line Items]
Amount of Interest, Dividends, and Fees Credited to Income			341	342
Realized Gain (Loss)			0	0
Investments, fair value, beginning balance			8,091	8,027
Gross Additions			0	0
Gross Reductions			0	0
Net Change in Unrealized Appreciation (Depreciation)			159	(51)
Investments, fair value, ending balance	$ 8,250	$ 7,976	$ 8,250	$ 7,976