Investments - Schedule of Investments at Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Sep. 30, 2024
Senior Secured First Lien Term Loans [Member]
Schedule of Investments at Amortized Cost and Fair Value [Line Items]
Amortized Cost	$ 133,693	$ 129,957
Percentage	41.80%	49.80%
Fair Value	$ 117,838	$ 113,990
Percentage	41.00%	50.00%
Senior Secured Notes [Member]
Schedule of Investments at Amortized Cost and Fair Value [Line Items]
Amortized Cost	$ 12,914	$ 18,127
Percentage	4.00%	7.00%
Fair Value	$ 13,099	$ 18,476
Percentage	4.60%	8.10%
Fund Investment [Member]
Schedule of Investments at Amortized Cost and Fair Value [Line Items]
Amortized Cost	$ 1,746	$ 1,746
Percentage	0.50%	0.70%
Fair Value	$ 1,600	$ 1,525
Percentage	0.60%	0.70%
Equity/Warrants [Member]
Schedule of Investments at Amortized Cost and Fair Value [Line Items]
Amortized Cost	$ 172,132	$ 110,930
Percentage	53.70%	42.50%
Fair Value	$ 154,306	$ 93,925
Percentage	53.80%	41.20%
Investments [Member]
Schedule of Investments at Amortized Cost and Fair Value [Line Items]
Amortized Cost	$ 320,485	$ 260,760
Percentage	100.00%	100.00%
Fair Value	$ 286,843	$ 227,916
Percentage	100.00%	100.00%

PhenixFIN Corp 10-Q