Borrowings - SBA Debentures Narrative (Details) - SBA Debentures $ in Millions	12 Months Ended
	Sep. 30, 2022 USD ($)
SBIC IV
Debt Instrument [Line Items]
Debt instrument, debentures commitment, amount	$ 150
SBIC V
Debt Instrument [Line Items]
Debt instrument, debentures commitment, amount	175
SBIC VI
Debt Instrument [Line Items]
Debt instrument, debentures commitment, amount	$ 175