Portfolio Investments - Changes in Fair Value of Level 3 Investments (Details)
$ in Thousands |
|
3 Months Ended |
|
|
|
Jul. 01, 2026
USD ($)
|
Sep. 30, 2026
USD ($)
investment
position
|
Sep. 30, 2025
USD ($)
investment
|
Jun. 30, 2026
USD ($)
|
Jun. 30, 2025
USD ($)
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
|
|
|
| Number of assets transferred out of Level 2 to Level 3 | investment |
|
|
|
2
|
|
|
|
| Number of equity positions transferred | position |
|
2
|
|
|
|
|
|
| Cost |
|
$ 5,944,319
|
|
|
$ 6,315,369
|
|
|
| Investments at fair value |
|
$ 5,944,478
|
[1] |
|
6,342,558
|
[2] |
|
| Subsidiaries | Reportable Legal Entities | Valley Electric Company, Inc. |
|
|
|
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
|
|
|
| Ownership interest disposed percent |
94.99%
|
94.99%
|
|
|
|
|
|
| First Lien, Unitranche |
|
|
|
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
|
|
|
| Cost |
|
$ 63,005
|
|
$ 202,687
|
219,582
|
|
$ 201,585
|
| Investments at fair value |
|
58,579
|
|
146,873
|
$ 155,717
|
|
$ 166,464
|
| Investments |
|
|
|
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
|
|
|
| Fair value, beginning balance |
$ 6,341,325
|
6,341,325
|
|
6,591,431
|
|
|
|
| Net realized (losses) gains on investments |
|
(66,923)
|
|
(1,889)
|
|
|
|
| Net change in unrealized (losses) gains |
|
(31,730)
|
|
46,811
|
|
|
|
| Net realized and unrealized (losses) gains |
|
(98,653)
|
|
44,922
|
|
|
|
| Purchases of portfolio investments |
|
71,445
|
|
70,013
|
|
|
|
| Payment-in-kind interest |
|
19,032
|
|
15,691
|
|
|
|
| Accretion of discounts and premiums, net |
|
1,280
|
|
632
|
|
|
|
| Decrease to Subordinated Structured Notes cost, net |
|
(1,837)
|
|
(15,371)
|
|
|
|
| Repayments and sales of portfolio investments |
|
(389,363)
|
|
(235,508)
|
|
|
|
| Transfers within Level 3 |
|
0
|
|
|
|
|
|
| Transfers out of Level 3 |
|
0
|
|
(34,450)
|
|
|
|
| Transfers into Level 3 |
|
125
|
|
43,456
|
|
|
|
| Fair value, ending balance |
|
5,943,354
|
|
6,480,816
|
|
|
|
| First Lien Revolving Line of Credit |
|
|
|
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
|
|
|
| Fair value, beginning balance |
72,378
|
72,378
|
|
68,350
|
|
|
|
| Net realized (losses) gains on investments |
|
0
|
|
0
|
|
|
|
| Net change in unrealized (losses) gains |
|
(3,554)
|
|
341
|
|
|
|
| Net realized and unrealized (losses) gains |
|
(3,554)
|
|
341
|
|
|
|
| Purchases of portfolio investments |
|
15,091
|
|
5,257
|
|
|
|
| Payment-in-kind interest |
|
958
|
|
565
|
|
|
|
| Accretion of discounts and premiums, net |
|
0
|
|
(23)
|
|
|
|
| Decrease to Subordinated Structured Notes cost, net |
|
0
|
|
0
|
|
|
|
| Repayments and sales of portfolio investments |
|
(2,556)
|
|
(4,623)
|
|
|
|
| Transfers within Level 3 |
|
0
|
|
|
|
|
|
| Transfers out of Level 3 |
|
0
|
|
0
|
|
|
|
| Transfers into Level 3 |
|
0
|
|
0
|
|
|
|
| Fair value, ending balance |
|
82,317
|
|
69,867
|
|
|
|
| First Lien Debt |
|
|
|
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
|
|
|
| Fair value, beginning balance |
4,215,364
|
4,215,364
|
|
4,351,777
|
|
|
|
| Net realized (losses) gains on investments |
|
(85,924)
|
|
4
|
|
|
|
| Net change in unrealized (losses) gains |
|
71,292
|
|
26,161
|
|
|
|
| Net realized and unrealized (losses) gains |
|
(14,632)
|
|
26,165
|
|
|
|
| Purchases of portfolio investments |
|
24,123
|
|
47,426
|
|
|
|
| Payment-in-kind interest |
|
13,170
|
|
15,126
|
|
|
|
| Accretion of discounts and premiums, net |
|
1,208
|
|
472
|
|
|
|
| Decrease to Subordinated Structured Notes cost, net |
|
0
|
|
0
|
|
|
|
| Repayments and sales of portfolio investments |
|
(236,262)
|
|
(145,154)
|
|
|
|
| Transfers within Level 3 |
|
(52,161)
|
|
|
|
|
|
| Transfers out of Level 3 |
|
0
|
|
0
|
|
|
|
| Transfers into Level 3 |
|
84
|
|
21,956
|
|
|
|
| Fair value, ending balance |
|
$ 3,950,894
|
|
$ 4,317,768
|
|
|
|
| Number of assets transferred out of Level 3 to Level 2 | investment |
|
3
|
|
1
|
|
|
|
| Number of assets transferred out of Level 2 to Level 3 | investment |
|
6
|
|
|
|
|
|
| Second Lien Revolving Line of Credit |
|
|
|
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
|
|
|
| Fair value, beginning balance |
1,854
|
$ 1,854
|
|
$ 0
|
|
|
|
| Net realized (losses) gains on investments |
|
0
|
|
0
|
|
|
|
| Net change in unrealized (losses) gains |
|
0
|
|
0
|
|
|
|
| Net realized and unrealized (losses) gains |
|
0
|
|
0
|
|
|
|
| Purchases of portfolio investments |
|
3,430
|
|
1,706
|
|
|
|
| Payment-in-kind interest |
|
0
|
|
0
|
|
|
|
| Accretion of discounts and premiums, net |
|
0
|
|
0
|
|
|
|
| Decrease to Subordinated Structured Notes cost, net |
|
0
|
|
0
|
|
|
|
| Repayments and sales of portfolio investments |
|
0
|
|
0
|
|
|
|
| Transfers within Level 3 |
|
0
|
|
|
|
|
|
| Transfers out of Level 3 |
|
0
|
|
0
|
|
|
|
| Transfers into Level 3 |
|
0
|
|
0
|
|
|
|
| Fair value, ending balance |
|
5,284
|
|
1,706
|
|
|
|
| Second Lien Debt |
|
|
|
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
|
|
|
| Fair value, beginning balance |
577,313
|
577,313
|
|
726,372
|
|
|
|
| Net realized (losses) gains on investments |
|
(88,823)
|
|
0
|
|
|
|
| Net change in unrealized (losses) gains |
|
92,778
|
|
(8,839)
|
|
|
|
| Net realized and unrealized (losses) gains |
|
3,955
|
|
(8,839)
|
|
|
|
| Purchases of portfolio investments |
|
0
|
|
0
|
|
|
|
| Payment-in-kind interest |
|
2,327
|
|
0
|
|
|
|
| Accretion of discounts and premiums, net |
|
72
|
|
183
|
|
|
|
| Decrease to Subordinated Structured Notes cost, net |
|
0
|
|
0
|
|
|
|
| Repayments and sales of portfolio investments |
|
(6,500)
|
|
(84,245)
|
|
|
|
| Transfers within Level 3 |
|
(8,429)
|
|
|
|
|
|
| Transfers out of Level 3 |
|
0
|
|
(34,450)
|
|
|
|
| Transfers into Level 3 |
|
41
|
|
21,500
|
|
|
|
| Fair value, ending balance |
|
$ 568,779
|
|
$ 620,521
|
|
|
|
| Number of assets transferred out of Level 3 to Level 2 | investment |
|
1
|
|
1
|
|
|
|
| Unsecured Debt |
|
|
|
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
|
|
|
| Fair value, beginning balance |
5,195
|
$ 5,195
|
|
$ 5,403
|
|
|
|
| Net realized (losses) gains on investments |
|
6
|
|
5
|
|
|
|
| Net change in unrealized (losses) gains |
|
18
|
|
(112)
|
|
|
|
| Net realized and unrealized (losses) gains |
|
24
|
|
(107)
|
|
|
|
| Purchases of portfolio investments |
|
0
|
|
0
|
|
|
|
| Payment-in-kind interest |
|
0
|
|
0
|
|
|
|
| Accretion of discounts and premiums, net |
|
0
|
|
0
|
|
|
|
| Decrease to Subordinated Structured Notes cost, net |
|
0
|
|
0
|
|
|
|
| Repayments and sales of portfolio investments |
|
(6)
|
|
(5)
|
|
|
|
| Transfers within Level 3 |
|
0
|
|
|
|
|
|
| Transfers out of Level 3 |
|
0
|
|
0
|
|
|
|
| Transfers into Level 3 |
|
0
|
|
0
|
|
|
|
| Fair value, ending balance |
|
5,213
|
|
5,291
|
|
|
|
| Subordinated Structured Notes |
|
|
|
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
|
|
|
| Fair value, beginning balance |
2,794
|
2,794
|
|
35,002
|
|
|
|
| Net realized (losses) gains on investments |
|
163
|
|
(2,740)
|
|
|
|
| Net change in unrealized (losses) gains |
|
(686)
|
|
4,415
|
|
|
|
| Net realized and unrealized (losses) gains |
|
(523)
|
|
1,675
|
|
|
|
| Purchases of portfolio investments |
|
0
|
|
0
|
|
|
|
| Payment-in-kind interest |
|
0
|
|
0
|
|
|
|
| Accretion of discounts and premiums, net |
|
0
|
|
0
|
|
|
|
| Decrease to Subordinated Structured Notes cost, net |
|
(1,837)
|
|
(15,371)
|
|
|
|
| Repayments and sales of portfolio investments |
|
(434)
|
|
(639)
|
|
|
|
| Transfers within Level 3 |
|
0
|
|
|
|
|
|
| Transfers out of Level 3 |
|
0
|
|
0
|
|
|
|
| Transfers into Level 3 |
|
0
|
|
0
|
|
|
|
| Fair value, ending balance |
|
0
|
|
20,667
|
|
|
|
| Distributions received, or entitled to be received, |
|
1,837
|
|
15,371
|
|
|
|
| Effective yield interest income recognized |
|
0
|
|
0
|
|
|
|
| Equity |
|
|
|
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
|
|
|
| Fair value, beginning balance |
$ 1,466,427
|
1,466,427
|
|
1,404,527
|
|
|
|
| Net realized (losses) gains on investments |
|
107,655
|
|
842
|
|
|
|
| Net change in unrealized (losses) gains |
|
(191,578)
|
|
24,845
|
|
|
|
| Net realized and unrealized (losses) gains |
|
(83,923)
|
|
25,687
|
|
|
|
| Purchases of portfolio investments |
|
28,801
|
|
15,624
|
|
|
|
| Payment-in-kind interest |
|
2,577
|
|
0
|
|
|
|
| Accretion of discounts and premiums, net |
|
0
|
|
0
|
|
|
|
| Decrease to Subordinated Structured Notes cost, net |
|
0
|
|
0
|
|
|
|
| Repayments and sales of portfolio investments |
|
(143,605)
|
|
(842)
|
|
|
|
| Transfers within Level 3 |
|
60,590
|
|
|
|
|
|
| Transfers out of Level 3 |
|
0
|
|
0
|
|
|
|
| Transfers into Level 3 |
|
0
|
|
0
|
|
|
|
| Fair value, ending balance |
|
$ 1,330,867
|
|
$ 1,444,996
|
|
|
|
|
|