FAIR VALUE OF FINANCIAL INSTRUMENTS - Assets Measured at Fair Value on Recurring and Non-recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Sep. 30, 2024
Level 1
Available-for-sale debt securities [Abstract]
Total debt securities AFS	$ 0	$ 0
Common equities and mutual funds	3,569	3,303
Level 2
Available-for-sale debt securities [Abstract]
Total debt securities AFS	1,411,520	1,741,221
Common equities and mutual funds	0	0
Level 3
Available-for-sale debt securities [Abstract]
Total debt securities AFS	0	0
Common equities and mutual funds	0	0
Recurring
Available-for-sale debt securities [Abstract]
Corporate securities	21,125	19,750
SBA securities	11,914	81,935
Obligations of states and political subdivisions	200	480
Non-bank qualified obligations of states and political subdivisions	192,002	217,990
Asset-backed securities	157,261	189,698
Mortgage-backed securities	1,029,018	1,231,368
Total debt securities AFS	1,411,520	1,741,221
Common equities and mutual funds	3,569	3,303
Non-marketable equity securities	12,829	11,828
Recurring \| Level 1
Available-for-sale debt securities [Abstract]
Corporate securities	0	0
SBA securities	0	0
Obligations of states and political subdivisions	0	0
Non-bank qualified obligations of states and political subdivisions	0	0
Asset-backed securities	0	0
Mortgage-backed securities	0	0
Total debt securities AFS	0	0
Common equities and mutual funds	3,569	3,303
Non-marketable equity securities	0	0
Recurring \| Level 2
Available-for-sale debt securities [Abstract]
Corporate securities	21,125	19,750
SBA securities	11,914	81,935
Obligations of states and political subdivisions	200	480
Non-bank qualified obligations of states and political subdivisions	192,002	217,990
Asset-backed securities	157,261	189,698
Mortgage-backed securities	1,029,018	1,231,368
Total debt securities AFS	1,411,520	1,741,221
Common equities and mutual funds	0	0
Non-marketable equity securities	0	0
Recurring \| Level 3
Available-for-sale debt securities [Abstract]
Corporate securities	0	0
SBA securities	0	0
Obligations of states and political subdivisions	0	0
Non-bank qualified obligations of states and political subdivisions	0	0
Asset-backed securities	0	0
Mortgage-backed securities	0	0
Total debt securities AFS	0	0
Common equities and mutual funds	0	0
Non-marketable equity securities	$ 0	$ 0

Fair value of asset backed securities investments classified as available for sale.

No definition available.

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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents common equities and mutual funds as of the balance sheet date which have been categorized as available-for-sale.

+ References

No definition available.

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- Definition

Corporate Securities Available For Sale

+ References

No definition available.

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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents non-bank qualified obligations of states and political subdivision as of the balance sheet date which have been categorized as available-for-sale.

+ References

No definition available.

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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents obligations of states and political subdivision as of the balance sheet date which have been categorized as available-for-sale.

+ References

No definition available.

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- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents debt securities issued by the Small Business Administration (SBA) as of the balance sheet date which have been categorized as available-for-sale.

+ References

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- References

No definition available.

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

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- Definition

Fair value of securitized, pay-through debt securities collateralized by real estate mortgage loans classified as available-for-sale.

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