Investments - Geographic Investment (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Schedule of Investments [Line Items]
Cost	$ 12,006,522	$ 9,934,159
Fair Value	$ 11,978,616	$ 9,868,440
Fair Value as % of Net Assets	210.10%	199.30%
Investment Owned, At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	100.00%	100.00%
United States
Schedule of Investments [Line Items]
Cost	$ 10,807,992	$ 9,381,707
Fair Value	$ 10,761,113	$ 9,317,684
Fair Value as % of Net Assets	188.80%	188.20%
United States | Investment Owned, At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	89.90%	94.40%
Canada
Schedule of Investments [Line Items]
Cost	$ 271,723	$ 275,579
Fair Value	$ 278,230	$ 278,103
Fair Value as % of Net Assets	4.90%	5.60%
Canada | Investment Owned, At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	2.30%	2.80%
Bermuda/Cayman Islands
Schedule of Investments [Line Items]
Cost	$ 439	$ 436
Fair Value	$ 600	$ 473
Fair Value as % of Net Assets	0.00%	0.00%
Bermuda/Cayman Islands | Investment Owned, At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	0.00%	0.00%
Europe
Schedule of Investments [Line Items]
Cost	$ 924,440	$ 276,437
Fair Value	$ 936,707	$ 272,180
Fair Value as % of Net Assets	16.40%	5.50%
Europe | Investment Owned, At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	7.80%	2.80%
Asia
Schedule of Investments [Line Items]
Cost	$ 1,928
Fair Value	$ 1,966
Fair Value as % of Net Assets	0.00%
Asia | Investment Owned, At Fair Value | Investment Type Concentration Risk
Schedule of Investments [Line Items]
Concentration Risk, Percentage	0.00%