Share Data and Distributions - Schedule of Changes in Net Assets (Details) - USD ($) $ in Thousands	3 Months Ended						6 Months Ended		9 Months Ended
	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2026	Mar. 31, 2025	Jun. 30, 2026	Jun. 30, 2025
Investment Company, Net Assets [Roll Forward]
Net assets at beginning of period	$ 4,402,669	$ 4,663,563	$ 4,541,805	$ 3,777,014	$ 3,412,316	$ 3,164,340	$ 4,541,805	$ 3,164,340	$ 4,541,805	$ 3,164,340
Issuance of Common shares in private and public offering	61,014	139,605	315,482	612,027	399,629	251,493
Issuance of Common shares under distribution reinvestment plan	21,213	25,600	29,550	26,795	25,204	23,524			76,363	75,523
Share repurchases, net of early repurchase deduction	(197,691)	(310,398)	(191,101)	(175,010)	(21,923)	(20,909)
Net investment income	91,244	96,312	102,293	82,956	77,254	72,205			289,849	232,415
Net unrealized appreciation (depreciation)	2,075	(78,015)	(32,141)	16,793	(30,913)	963
Net realized gains (losses)	(9,864)	(28,440)	6,953	(15,991)	6,540	3,677
Provision for income tax (expense) benefit	(28)	78	(87)	(3)	19	(65)			(37)	(49)
Distributions to shareholders	(92,988)	(105,636)	(109,191)	(107,821)	(91,112)	(82,912)
Net assets at end of period	$ 4,277,644	$ 4,402,669	$ 4,663,563	$ 4,216,760	$ 3,777,014	$ 3,412,316	$ 4,402,669	$ 3,777,014	$ 4,277,644	$ 4,216,760
Common Shares
Investment Company, Net Assets [Roll Forward]
Net assets beginning of period (in shares)	196,722	203,377	196,721	162,226	145,073	134,288	196,721	134,288	196,721	134,288
Net assets at beginning of period	$ 1,967	$ 2,033	$ 1,967	$ 1,622	$ 1,451	$ 1,343	$ 1,967	$ 1,343	$ 1,967	$ 1,343
Issuance of Common Shares in private and public offering (in shares)	2,725	6,109	13,705	26,377	17,030	10,676
Issuance of Common shares in private and public offering	$ 27	$ 61	$ 136	$ 264	$ 171	$ 107
Issuance of Common Shares under distribution reinvestment plan (in shares)	1,022	1,105	1,285	1,164	1,065	999
Issuance of Common shares under distribution reinvestment plan	$ 10	$ 11	$ 13	$ 12	$ 10	$ 10
Shares repurchased, net of early repurchase deduction (in shares)	(8,857)	(13,869)	(8,334)	(7,563)	(942)	(890)
Share repurchases, net of early repurchase deduction	$ (88)	$ (138)	$ (83)	$ (76)	$ (10)	$ (9)
Net assets end of period (in shares)	191,612	196,722	203,377	182,204	162,226	145,073	196,722	162,226	191,612	182,204
Net assets at end of period	$ 1,916	$ 1,967	$ 2,033	$ 1,822	$ 1,622	$ 1,451	$ 1,967	$ 1,622	$ 1,916	$ 1,822
Additional Paid-in-Capital
Investment Company, Net Assets [Roll Forward]
Net assets at beginning of period	4,600,564	4,745,691	4,591,826	3,827,485	3,424,746	3,170,746	4,591,826	3,170,746	4,591,826	3,170,746
Issuance of Common shares in private and public offering	60,987	139,544	315,346	611,763	399,458	251,386
Issuance of Common shares under distribution reinvestment plan	21,203	25,589	29,537	26,783	25,194	23,514
Share repurchases, net of early repurchase deduction	(197,603)	(310,260)	(191,018)	(174,934)	(21,913)	(20,900)
Net assets at end of period	4,485,151	4,600,564	4,745,691	4,291,097	3,827,485	3,424,746	4,600,564	3,827,485	4,485,151	4,291,097
Accumulated Distributable Earnings (Loss)
Investment Company, Net Assets [Roll Forward]
Net assets at beginning of period	(199,862)	(84,161)	(51,988)	(52,093)	(13,881)	(7,749)	(51,988)	(7,749)	(51,988)	(7,749)
Net investment income	91,244	96,312	102,293	82,956	77,254	72,205
Net unrealized appreciation (depreciation)	2,075	(78,015)	(32,141)	16,793	(30,913)	963
Net realized gains (losses)	(9,864)	(28,440)	6,953	(15,991)	6,540	3,677
Provision for income tax (expense) benefit	(28)	78	(87)	(3)	19	(65)
Distributions to shareholders	(92,988)	(105,636)	(109,191)	(107,821)	(91,112)	(82,912)
Net assets at end of period	$ (209,423)	$ (199,862)	$ (84,161)	$ (76,159)	$ (52,093)	$ (13,881)	$ (199,862)	$ (52,093)	$ (209,423)	$ (76,159)