Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Cash Flows from Operating Activities
Net Increase (Decrease) in Net Assets Resulting from Operations	$ 195,562	$ (34,946)	$ 397,405	$ 9,039
Adjustments to reconcile net increase (decrease) in net assets resulting from operations to net cash used in operating activities:
Purchases of investments, net			(565,832)	(1,376,470)
Proceeds from investments and investment repayments, net			867,881	1,285,718
Net amortization/accretion of premium/discount on investments			(18,648)	(23,467)
Payment-in-kind interest and dividends			(113,628)	(69,210)
Net change in unrealized (gain) loss on investments			(85,668)	238,306
Net change in unrealized gain (loss) on interest rate swap attributed to unsecured notes			2,723	(65,238)
Net change in unrealized (gains) losses on translation of assets and liabilities in foreign currencies			(2,552)	4,071
Net realized (gain) loss on investments	(118)	51	52,365	(4,651)
Net realized (gain) loss on foreign currency transactions relating to investments			23	(6)
Amortization of debt issuance costs	7,562	8,697	14,426	14,807
Changes in operating assets and liabilities:
(Increase) decrease in interest receivable			318	12,654
(Increase) decrease in receivable from a controlled affiliate			(1,593)	(19,242)
(Increase) decrease in prepaid expenses and other assets			(1,744)	18,975
Increase (decrease) in management fee payable			440	103
Increase (decrease) in incentive fee payable			5,136	(2,701)
Increase (decrease) in payables to affiliate			143	(1,490)
Increase (decrease) in payables for investments purchased			0	0
Increase (decrease) in accrued expenses and other liabilities			(8,382)	53,544
Net cash provided by (used in) operating activities			542,813	74,742
Cash Flows from Financing Activities
Borrowings on debt			575,492	1,389,480
Payments on debt			(859,000)	(1,319,000)
Debt issuance costs			(4,748)	(6,658)
Repurchases of common stock			(34,058)	(10,015)
Cash distributions paid to shareholders			(297,691)	(232,435)
Net cash provided by (used in) financing activities			(620,005)	(178,628)
Net increase (decrease) in cash and restricted cash, including foreign cash (restricted cash of $(3,445) and $75,893, respectively)			(77,192)	(103,886)
Cash and restricted cash, including foreign cash, beginning of period (restricted cash of $96,420 and $21,481, respectively)			445,087	447,145	$ 447,145
Cash and restricted cash, including foreign cash, end of period (restricted cash of $92,975 and $97,374, respectively)	367,895	343,259	367,895	343,259	$ 445,087
Supplemental and Non-Cash Information
Interest paid during the period			190,971	101,231
Distributions declared during the period			296,786	244,404
Reinvestment of distributions during the period			0	11,951
Distributions Payable	$ 128,612	$ 122,085	128,612	122,085
Taxes, including excise tax, paid during the period			$ 1,495	$ 1,266