Fair Value Measurements - Narrative (Details) - USD ($) |
9 Months Ended | ||
|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Sep. 30, 2025 |
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| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | |||
| Available-for-sale securities purchased | $ 1,161,720,000 | $ 1,218,796,000 | |
| Proceeds from sales of available-for-sale securities | 77,171,000 | 797,000 | |
| Held-to-maturity securities purchased | 278,367,000 | 114,182,000 | |
| Proceeds from sale of held-to-maturity securities | $ 0 | $ 0 | |
| Term of contractual due dates, mortgage-backed securities | 25 years | ||
| Accrued interest for available-for-sale securities | $ 14,748,000 | $ 11,057,000 | |
| Accrued interest for held-to-maturity securities | 3,039,000 | $ 2,089,000 | |
| Consumer loans | Single-family residential | |||
| New Accounting Pronouncements or Change in Accounting Principle [Line Items] | |||
| Foreclosed residential real estate properties held as REO | 551,000 | ||
| Real estate acquired through foreclosure | $ 8,010,000 | ||
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- Definition Amount, after allowance for credit loss, of accrued interest on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount, after allowance for credit loss, of accrued interest on investment in debt security measured at amortized cost (held-to-maturity). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition 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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Carrying amount of other real estate not separately disclosed, including, but not limited to, real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. This does not include real estate assets taken in settlement of troubled loans through surrender or foreclosure. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Amount of cash outflow to acquire investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of cash outflow through purchase of long-term held-to-maturity securities. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition The cash inflow associated with the sale of securities that had been designated as held-to-maturity. Excludes proceeds from maturities, prepayments and calls by the issuer. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Term of Contractual Due Dates of Substantially All Mortgage-Backed Securities No definition available.
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- Details
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- Details
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