v3.26.1
Investments - Schedule of Portfolio Composition by Industry at Amortization Cost and Fair Value (Details) - USD ($)
$ in Thousands
9 Months Ended 12 Months Ended
Jun. 30, 2026
Sep. 30, 2025
Schedule of Investments [Line Items]    
Amortized Cost $ 2,674,753 $ 2,176,447
Fair Value $ 2,667,489 [1] $ 2,209,174 [2]
Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 100.00% 100.00%
Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 100.00% 100.00%
Aerospace & Defense    
Schedule of Investments [Line Items]    
Amortized Cost $ 57,103 $ 24,586
Fair Value $ 56,943 $ 24,652
Aerospace & Defense | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 2.10% 1.10%
Aerospace & Defense | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 2.10% 1.10%
Air Freight & Logistics    
Schedule of Investments [Line Items]    
Amortized Cost $ 22,767 $ 22,726
Fair Value $ 23,132 $ 23,033
Air Freight & Logistics | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.90% 1.00%
Air Freight & Logistics | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.90% 1.00%
Auto Components    
Schedule of Investments [Line Items]    
Amortized Cost $ 38,873 $ 36,496
Fair Value $ 39,252 $ 36,957
Auto Components | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.50% 1.70%
Auto Components | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.50% 1.70%
Automobiles    
Schedule of Investments [Line Items]    
Amortized Cost $ 147,681 $ 98,937
Fair Value $ 149,602 $ 101,466
Automobiles | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 5.50% 4.60%
Automobiles | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 5.60% 4.60%
Banks    
Schedule of Investments [Line Items]    
Amortized Cost $ 12,476 $ 9,356
Fair Value $ 12,266 $ 9,456
Banks | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.50% 0.40%
Banks | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.50% 0.40%
Beverages    
Schedule of Investments [Line Items]    
Amortized Cost $ 25,666 $ 25,503
Fair Value $ 25,936 $ 26,202
Beverages | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.00% 1.20%
Beverages | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.00% 1.20%
Building Products    
Schedule of Investments [Line Items]    
Amortized Cost $ 1,012 $ 677
Fair Value $ 1,017 $ 693
Building Products | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.00% 0.00%
Building Products | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.00% 0.00%
Capital Markets    
Schedule of Investments [Line Items]    
Amortized Cost $ 24,731 $ 22,977
Fair Value $ 24,534 $ 23,193
Capital Markets | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.90% 1.10%
Capital Markets | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.90% 1.10%
Chemicals    
Schedule of Investments [Line Items]    
Amortized Cost $ 6,461 $ 6,453
Fair Value $ 6,446 $ 6,475
Chemicals | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.20% 0.30%
Chemicals | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.20% 0.30%
Commercial Services & Supplies    
Schedule of Investments [Line Items]    
Amortized Cost $ 83,947 $ 95,995
Fair Value $ 83,855 $ 96,815
Commercial Services & Supplies | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 3.10% 4.40%
Commercial Services & Supplies | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 3.10% 4.40%
Construction & Engineering    
Schedule of Investments [Line Items]    
Amortized Cost $ 18,722 $ 17,379
Fair Value $ 18,643 $ 17,502
Construction & Engineering | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.70% 0.80%
Construction & Engineering | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.70% 0.80%
Containers & Packaging    
Schedule of Investments [Line Items]    
Amortized Cost $ 5,266 $ 1,715
Fair Value $ 5,170 $ 1,718
Containers & Packaging | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.20% 0.10%
Containers & Packaging | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.20% 0.10%
Diversified Consumer Services    
Schedule of Investments [Line Items]    
Amortized Cost $ 173,006 $ 148,679
Fair Value $ 171,725 $ 150,189
Diversified Consumer Services | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 6.50% 6.80%
Diversified Consumer Services | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 6.40% 6.80%
Diversified Financial Services    
Schedule of Investments [Line Items]    
Amortized Cost $ 72,881 $ 62,615
Fair Value $ 72,914 $ 63,719
Diversified Financial Services | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 2.70% 2.90%
Diversified Financial Services | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 2.70% 2.90%
Electric Utilities    
Schedule of Investments [Line Items]    
Amortized Cost $ 1,965 $ 1,903
Fair Value $ 2,066 $ 1,997
Electric Utilities | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.10% 0.10%
Electric Utilities | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.10% 0.10%
Electrical Equipment    
Schedule of Investments [Line Items]    
Amortized Cost $ 0 $ 7,028
Fair Value $ 0 $ 7,157
Electrical Equipment | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.00% 0.30%
Electrical Equipment | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.00% 0.30%
Electronic Equipment, Instruments & Components    
Schedule of Investments [Line Items]    
Amortized Cost $ 5,181 $ 5,184
Fair Value $ 5,234 $ 5,345
Electronic Equipment, Instruments & Components | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.20% 0.20%
Electronic Equipment, Instruments & Components | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.20% 0.20%
Food & Staples Retailing    
Schedule of Investments [Line Items]    
Amortized Cost $ 2,285 $ 0
Fair Value $ 2,231 $ 0
Food & Staples Retailing | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.10% 0.00%
Food & Staples Retailing | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.10% 0.00%
Food Products    
Schedule of Investments [Line Items]    
Amortized Cost $ 33,047 $ 32,759
Fair Value $ 33,281 $ 33,072
Food Products | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.20% 1.50%
Food Products | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.30% 1.50%
Healthcare Equipment & Supplies    
Schedule of Investments [Line Items]    
Amortized Cost $ 113,203 $ 51,101
Fair Value $ 113,225 $ 51,329
Healthcare Equipment & Supplies | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 4.20% 2.30%
Healthcare Equipment & Supplies | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 4.20% 2.30%
Healthcare Providers & Services    
Schedule of Investments [Line Items]    
Amortized Cost $ 121,691 $ 106,401
Fair Value $ 122,151 $ 108,172
Healthcare Providers & Services | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 4.60% 4.90%
Healthcare Providers & Services | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 4.60% 4.90%
Healthcare Technology    
Schedule of Investments [Line Items]    
Amortized Cost $ 151,350 $ 108,643
Fair Value $ 150,991 $ 109,991
Healthcare Technology | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 5.70% 5.00%
Healthcare Technology | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 5.70% 5.00%
Hotels, Restaurants & Leisure    
Schedule of Investments [Line Items]    
Amortized Cost $ 156,351 $ 127,364
Fair Value $ 156,398 $ 128,251
Hotels, Restaurants & Leisure | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 5.90% 5.90%
Hotels, Restaurants & Leisure | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 5.90% 5.80%
Household Durables    
Schedule of Investments [Line Items]    
Amortized Cost $ 2,011 $ 0
Fair Value $ 2,008 $ 0
Household Durables | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.10% 0.00%
Household Durables | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.10% 0.00%
Household Products    
Schedule of Investments [Line Items]    
Amortized Cost $ 2,710 $ 2,728
Fair Value $ 2,687 $ 2,744
Household Products | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.10% 0.10%
Household Products | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.10% 0.10%
Industrial Conglomerates    
Schedule of Investments [Line Items]    
Amortized Cost $ 50,325 $ 28,527
Fair Value $ 51,572 $ 30,631
Industrial Conglomerates | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.90% 1.30%
Industrial Conglomerates | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.90% 1.40%
Insurance    
Schedule of Investments [Line Items]    
Amortized Cost $ 159,581 $ 117,345
Fair Value $ 159,491 $ 119,150
Insurance | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 6.00% 5.40%
Insurance | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 6.00% 5.40%
IT Services    
Schedule of Investments [Line Items]    
Amortized Cost $ 54,676 $ 44,242
Fair Value $ 54,064 $ 44,632
IT Services | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 2.00% 2.00%
IT Services | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 2.00% 2.00%
Leisure Products    
Schedule of Investments [Line Items]    
Amortized Cost $ 37,755 $ 36,537
Fair Value $ 37,666 $ 36,536
Leisure Products | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.40% 1.70%
Leisure Products | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.40% 1.70%
Life Sciences Tools & Services    
Schedule of Investments [Line Items]    
Amortized Cost $ 41,286 $ 23,565
Fair Value $ 40,860 $ 24,992
Life Sciences Tools & Services | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.50% 1.10%
Life Sciences Tools & Services | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.50% 1.10%
Machinery    
Schedule of Investments [Line Items]    
Amortized Cost $ 33,835 $ 31,475
Fair Value $ 33,685 $ 31,741
Machinery | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.30% 1.40%
Machinery | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.30% 1.40%
Media    
Schedule of Investments [Line Items]    
Amortized Cost $ 16,548 $ 14,869
Fair Value $ 16,590 $ 14,886
Media | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.60% 0.70%
Media | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.60% 0.70%
Oil, Gas & Consumable Fuels    
Schedule of Investments [Line Items]    
Amortized Cost $ 32,676 $ 25,311
Fair Value $ 32,812 $ 25,498
Oil, Gas & Consumable Fuels | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.20% 1.20%
Oil, Gas & Consumable Fuels | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.20% 1.20%
Pharmaceuticals    
Schedule of Investments [Line Items]    
Amortized Cost $ 29,268 $ 21,811
Fair Value $ 29,298 $ 22,245
Pharmaceuticals | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.10% 1.00%
Pharmaceuticals | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 1.10% 1.00%
Professional Services    
Schedule of Investments [Line Items]    
Amortized Cost $ 88,632 $ 79,954
Fair Value $ 87,468 $ 80,355
Professional Services | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 3.30% 3.70%
Professional Services | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 3.30% 3.70%
Road & Rail    
Schedule of Investments [Line Items]    
Amortized Cost $ 0 $ 13,840
Fair Value $ 0 $ 13,930
Road & Rail | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.00% 0.60%
Road & Rail | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.00% 0.60%
Software    
Schedule of Investments [Line Items]    
Amortized Cost $ 699,054 $ 577,485
Fair Value $ 693,339 $ 590,302
Software | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 26.10% 26.50%
Software | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 26.00% 26.70%
Specialty Retail    
Schedule of Investments [Line Items]    
Amortized Cost $ 129,188 $ 126,438
Fair Value $ 127,475 $ 126,384
Specialty Retail | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 4.80% 5.80%
Specialty Retail | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 4.80% 5.70%
Transportation Infrastructure    
Schedule of Investments [Line Items]    
Amortized Cost $ 16,330 $ 16,060
Fair Value $ 16,248 $ 15,965
Transportation Infrastructure | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.60% 0.80%
Transportation Infrastructure | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.60% 0.70%
Water Utilities    
Schedule of Investments [Line Items]    
Amortized Cost $ 5,213 $ 1,783
Fair Value $ 5,214 $ 1,799
Water Utilities | Investments, at Amortized Cost | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.20% 0.10%
Water Utilities | Investments, at Fair Value | Industry Concentration Risk    
Schedule of Investments [Line Items]    
Concentration risk, percentage 0.20% 0.10%
[1] The fair values of investments were valued using significant unobservable inputs, unless otherwise noted. See Note 7. The fair value of loan investments may include the impact of the unfunded commitment being valued below par.
[2] The fair values of investments were valued using significant unobservable inputs, unless otherwise noted. See Note 7. The fair value of loan investments may include the impact of the unfunded commitment being valued below par.