Investments - Schedule of Composition Of Investment (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Cost	$ 5,303,265	$ 4,427,510
Total Investments before Cash Equivalents, Fair Value	5,287,232	4,308,892
Total Cash Equivalents, Cost	240,002	4
Total Cash Equivalents, Fair Value	240,002	4
Total Investments after Cash Equivalents, Cost	5,543,267	4,427,514
Total Investments after Cash Equivalents, Fair Value	5,527,234	4,308,896
Total Assets and Liabilities at Fair Value, Cost	5,543,267	4,427,514
Total Assets and Liabilities at Fair Value	5,514,685	4,308,685
Level 1
Schedule of Investments [Line Items]
Total Cash Equivalents, Fair Value	240,002	4
Total Investments after Cash Equivalents, Fair Value	240,002	4
Total Assets and Liabilities at Fair Value	240,002	4
Level 2
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Fair Value	1,428,194	1,478,661
Total Investments after Cash Equivalents, Fair Value	1,428,194	1,478,661
Total Assets and Liabilities at Fair Value	1,415,645	1,478,450
Level 3
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Fair Value	3,859,038	2,830,231
Total Investments after Cash Equivalents, Fair Value	3,859,038	2,830,231
Total Assets and Liabilities at Fair Value	3,859,038	2,830,231
Money Market Fund
Schedule of Investments [Line Items]
Total Cash Equivalents, Cost	240,002	4
Total Cash Equivalents, Fair Value	240,002	4
Money Market Fund | Level 1
Schedule of Investments [Line Items]
Total Cash Equivalents, Fair Value	240,002	4
First Lien Secured Debt
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Cost	5,247,771	4,357,934
Total Investments before Cash Equivalents, Fair Value	5,241,795	4,266,966
First Lien Secured Debt | Level 2
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Fair Value	1,413,988	1,436,996
First Lien Secured Debt | Level 3
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Fair Value	3,827,807	2,829,970
Second Lien Secured Debt
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Cost	39,544
Total Investments before Cash Equivalents, Fair Value	30,716
Second Lien Secured Debt | Level 3
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Fair Value	30,716
Unsecured Debt
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Cost	15,460	69,276
Total Investments before Cash Equivalents, Fair Value	14,206	41,665
Unsecured Debt | Level 2
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Fair Value	14,206	41,665
Common Equity/Interests
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Cost	390	200
Total Investments before Cash Equivalents, Fair Value	480	205
Common Equity/Interests | Level 3
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Fair Value	480	205
Preferred Equity
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Cost	100	100
Total Investments before Cash Equivalents, Fair Value	35	56
Preferred Equity | Level 3
Schedule of Investments [Line Items]
Total Investments before Cash Equivalents, Fair Value	35	56
Interest Rate Swap
Schedule of Investments [Line Items]
Total Assets and Liabilities at Fair Value	(13,621)	(460)
Interest Rate Swap | Level 2
Schedule of Investments [Line Items]
Total Assets and Liabilities at Fair Value	(13,621)	(460)
Foreign Exchange Forward Transactions
Schedule of Investments [Line Items]
Total Assets and Liabilities at Fair Value	1,072	249
Foreign Exchange Forward Transactions | Level 2
Schedule of Investments [Line Items]
Total Assets and Liabilities at Fair Value	$ 1,072	$ 249