SECURITIES - Narrative (Details)	12 Months Ended
SECURITIES - Narrative (Details)	Sep. 30, 2025 USD ($) security	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)
Debt Securities, Available-for-sale [Line Items]
Proceeds from sales of securities available for sale	$ 239,322,000	$ 0	$ 0
Number of securities in an unrealized loss position \| security	147
Securities pledged as collateral for public funds on deposit	$ 0	0
Securities pledged as collateral for individual, trust, and estate deposits	0	0
Federal reserve bank stock	19,700,000	19,700,000
Federal Reserve Bank and Federal Home Loan Bank Stock, at cost	5,000,000.0	16,300,000
Total loans and leases, net	4,611,589,000	4,003,430,000
Determinable fair value	12,000,000.0	13,600,000
Impairment recognized	3,000,000.0	1,000,000.0	3,300,000
Marketable
Debt Securities, Available-for-sale [Line Items]
Equity securities	3,800,000	3,300,000
Unrealized loss	100,000	100,000
Non-marketable
Debt Securities, Available-for-sale [Line Items]
Equity securities	13,200,000	11,800,000
Unrealized gains (losses) on marketable equity securities	1,600,000	1,100,000
Realized gains on marketable equity securities	$ 400,000
Number of equity securities sold \| security	1
Non-marketable \| Visa Class C Common Stock and Visa Class B-2 Common Stock
Debt Securities, Available-for-sale [Line Items]
Realized gains on marketable equity securities	$ 400,000	2,400,000
Estimated Fair Value
Debt Securities, Available-for-sale [Line Items]
Fair value	4,599,269,000	4,036,490,000
Federal Reserve Bank
Debt Securities, Available-for-sale [Line Items]
Interest and dividend income from FLHB	1,200,000	1,200,000	1,200,000
Federal Home Loan Bank
Debt Securities, Available-for-sale [Line Items]
Interest and dividend income from FLHB	600,000	700,000	$ 500,000
Asset Pledged as Collateral
Debt Securities, Available-for-sale [Line Items]
Investments	385,500,000	533,800,000
Total loans and leases, net	223,000,000.0	136,900,000
Asset Pledged as Collateral with Right \| Estimated Fair Value \| Federal Home Loan Bank Advances
Debt Securities, Available-for-sale [Line Items]
Fair value	$ 955,300,000	$ 1,040,000,000.00

PATHWARD FINANCIAL, INC. 10-K