SECURITIES - Narrative (Details) $ in Thousands	9 Months Ended
Jun. 30, 2025 USD ($) security	Jun. 30, 2024 USD ($)	Sep. 30, 2024 USD ($)
Debt Securities, Available-for-sale [Line Items]
Proceeds from sales of securities available for sale	$ 217,883	$ 0
AFS number of securities in an unrealized loss position (in securities) \| security	153
Federal reserve bank stock	$ 19,700		$ 19,700
Federal home loan bank stock	9,800		16,300
Marketable
Debt Securities, Available-for-sale [Line Items]
Equity securities	3,700		3,300
Unrealized gain (loss)	(100)	(200)
Non-marketable
Debt Securities, Available-for-sale [Line Items]
Equity securities	12,700		11,800
Unrealized gain (loss)	1,100	$ 600
Equity securities without readily determinable fair value, amount	14,700		$ 13,600
Realized gain on equity securities	$ 400
Number of equity securities sold \| security	0

Number of Equity Securities Sold

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Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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