Fair Value of Investments - Schedule of Carrying and Fair Values of the Company’s Debt Obligations (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Debt obligations	$ 6,756,767	$ 6,909,235
Debt issuance costs, net	80,535	95,647
Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	7,062,399	7,281,744
Fair Value
Debt Instrument [Line Items]
Debt obligations	6,756,767	6,909,235
Level 1
Debt Instrument [Line Items]
Debt obligations	0	0
Level 2
Debt Instrument [Line Items]
Debt obligations	3,763,625	3,679,375
Level 3
Debt Instrument [Line Items]
Debt obligations	2,993,142	3,229,860
Line of Credit | SPV Asset Facility II
Debt Instrument [Line Items]
Debt issuance costs, net	4,400	4,600
Line of Credit | SPV Asset Facility II | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	135,617	245,368
Line of Credit | SPV Asset Facility II | Fair Value
Debt Instrument [Line Items]
Debt obligations	135,617	245,368
Line of Credit | SPV Asset Facility III
Debt Instrument [Line Items]
Debt issuance costs, net		600
Line of Credit | SPV Asset Facility III | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	0	249,372
Line of Credit | SPV Asset Facility III | Fair Value
Debt Instrument [Line Items]
Debt obligations	0	249,372
Line of Credit | CLO I
Debt Instrument [Line Items]
Debt issuance costs, net		2,700
Secured Debt | CLO I
Debt Instrument [Line Items]
Debt issuance costs, net	2,500	2,700
Secured Debt | CLO I | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	384,328	387,321
Secured Debt | CLO I | Fair Value
Debt Instrument [Line Items]
Debt obligations	384,328	387,321
Secured Debt | CLO II
Debt Instrument [Line Items]
Debt issuance costs, net	2,600	2,800
Secured Debt | CLO II | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	257,405	257,206
Secured Debt | CLO II | Fair Value
Debt Instrument [Line Items]
Debt obligations	257,405	257,206
Secured Debt | CLO III
Debt Instrument [Line Items]
Debt issuance costs, net	1,700	1,900
Secured Debt | CLO III | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	258,263	258,145
Secured Debt | CLO III | Fair Value
Debt Instrument [Line Items]
Debt obligations	258,263	258,145
Secured Debt | CLO IV
Debt Instrument [Line Items]
Debt issuance costs, net	4,400	4,700
Secured Debt | CLO IV | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	288,061	287,777
Secured Debt | CLO IV | Fair Value
Debt Instrument [Line Items]
Debt obligations	288,061	287,777
Secured Debt | CLO V
Debt Instrument [Line Items]
Debt issuance costs, net	2,700	2,800
Secured Debt | CLO V | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	506,941	506,792
Secured Debt | CLO V | Fair Value
Debt Instrument [Line Items]
Debt obligations	506,941	506,792
Secured Debt | CLO VI
Debt Instrument [Line Items]
Debt issuance costs, net	1,600	1,700
Secured Debt | CLO VI | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	258,396	258,271
Secured Debt | CLO VI | Fair Value
Debt Instrument [Line Items]
Debt obligations	258,396	258,271
Secured Debt | CLO VII
Debt Instrument [Line Items]
Debt issuance costs, net	1,900	2,000
Secured Debt | CLO VII | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	237,232	237,155
Secured Debt | CLO VII | Fair Value
Debt Instrument [Line Items]
Debt obligations	237,232	237,155
Secured Debt | CLO X
Debt Instrument [Line Items]
Debt issuance costs, net	1,900
Secured Debt | CLO X | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	258,093	0
Secured Debt | CLO X | Fair Value
Debt Instrument [Line Items]
Debt obligations	258,093	0
Unsecured debt | 2024 Notes
Debt Instrument [Line Items]
Debt issuance costs, net	1,200	2,900
Unsecured debt | 2024 Notes | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	392,062	384,851
Unsecured debt | 2024 Notes | Fair Value
Debt Instrument [Line Items]
Debt obligations	397,000	395,000
Unsecured debt | 2025 Notes
Debt Instrument [Line Items]
Debt issuance costs, net	2,600	3,800
Unsecured debt | 2025 Notes | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	422,459	421,242
Unsecured debt | 2025 Notes | Fair Value
Debt Instrument [Line Items]
Debt obligations	403,750	399,500
Unsecured debt | July 2025 Notes
Debt Instrument [Line Items]
Debt issuance costs, net	3,300	4,700
Unsecured debt | July 2025 Notes | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	496,670	495,347
Unsecured debt | July 2025 Notes | Fair Value
Debt Instrument [Line Items]
Debt obligations	468,750	462,500
Unsecured debt | 2026 Notes
Debt Instrument [Line Items]
Debt issuance costs, net	5,200	6,800
Unsecured debt | 2026 Notes | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	494,772	493,162
Unsecured debt | 2026 Notes | Fair Value
Debt Instrument [Line Items]
Debt obligations	467,500	461,250
Unsecured debt | July 2026 Notes
Debt Instrument [Line Items]
Debt issuance costs, net	13,600	17,000
Unsecured debt | July 2026 Notes | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	986,434	982,993
Unsecured debt | July 2026 Notes | Fair Value
Debt Instrument [Line Items]
Debt obligations	897,500	875,000
Unsecured debt | 2027 Notes
Debt Instrument [Line Items]
Debt issuance costs, net	6,500	7,900
Unsecured debt | 2027 Notes | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	439,095	438,332
Unsecured debt | 2027 Notes | Fair Value
Debt Instrument [Line Items]
Debt obligations	430,000	412,500
Unsecured debt | 2028 Notes
Debt Instrument [Line Items]
Debt issuance costs, net	12,200	14,000
Unsecured debt | 2028 Notes | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	837,765	835,957
Unsecured debt | 2028 Notes | Fair Value
Debt Instrument [Line Items]
Debt obligations	699,125	673,625
Revolving Credit Facility | Line of Credit
Debt Instrument [Line Items]
Debt issuance costs, net	12,200	14,700
Revolving Credit Facility | Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Debt issuance costs, net	12,200	14,700
Revolving Credit Facility | Line of Credit | Revolving Credit Facility | Net Carrying Value
Debt Instrument [Line Items]
Debt obligations	408,806	542,453
Revolving Credit Facility | Line of Credit | Revolving Credit Facility | Fair Value
Debt Instrument [Line Items]
Debt obligations	$ 408,806	$ 542,453