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Fair Value Measurements - Recurring (Details) - USD ($) $ in Thousands | Mar. 31, 2022 | Sep. 30, 2021
--- | --- | ---
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | $ 1,909,605 | $ 2,138,259
Total financial assets | 2,203,959 | 2,517,806
Recurring |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 1,909,605 | 2,138,259
Total financial assets | 2,061,450 | 2,191,684
Total financial liabilities | 27,391 | 14,801
Recurring | Client swap program hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative assets | 27,353 | 10,983
Derivative liabilities | 27,353 | 10,983
Recurring | Commercial loan fair value hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative liabilities | 38 | 2,177
Recurring | Mortgage loan fair value hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative assets | 19,281 |
Derivative liabilities |  | 1,641
Recurring | Borrowings cash flow hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative assets | 105,211 | 42,442
Recurring | U.S. government and agency securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 49,809 | 61,779
Recurring | Asset-backed securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 889,426 | 1,078,681
Recurring | Municipal bonds |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 38,468 | 39,984
Recurring | Corporate debt securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 333,999 | 350,988
Recurring | Agency pass-through certificates |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 597,903 | 606,827
Recurring | Level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 0 | 0
Total financial assets | 0 | 0
Total financial liabilities | 0 | 0
Recurring | Level 1 | Client swap program hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative assets | 0 | 0
Derivative liabilities | 0 | 0
Recurring | Level 1 | Commercial loan fair value hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative liabilities | 0 | 0
Recurring | Level 1 | Mortgage loan fair value hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative assets | 0 |
Derivative liabilities |  |
Recurring | Level 1 | Borrowings cash flow hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative assets | 0 | 0
Recurring | Level 1 | U.S. government and agency securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 0 | 0
Recurring | Level 1 | Asset-backed securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 0 | 0
Recurring | Level 1 | Municipal bonds |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 0 | 0
Recurring | Level 1 | Corporate debt securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 0 | 0
Recurring | Level 1 | Agency pass-through certificates |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 0 | 0
Recurring | Level 2 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 1,909,605 | 2,138,259
Total financial assets | 2,061,450 | 2,191,684
Total financial liabilities | 27,391 | 14,801
Recurring | Level 2 | Client swap program hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative assets | 27,353 | 10,983
Derivative liabilities | 27,353 | 10,983
Recurring | Level 2 | Commercial loan fair value hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative liabilities | 38 | 2,177
Recurring | Level 2 | Mortgage loan fair value hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative assets | 19,281 |
Derivative liabilities |  | 1,641
Recurring | Level 2 | Borrowings cash flow hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative assets | 105,211 | 42,442
Recurring | Level 2 | U.S. government and agency securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 49,809 | 61,779
Recurring | Level 2 | Asset-backed securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 889,426 | 1,078,681
Recurring | Level 2 | Municipal bonds |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 38,468 | 39,984
Recurring | Level 2 | Corporate debt securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 333,999 | 350,988
Recurring | Level 2 | Agency pass-through certificates |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 597,903 | 606,827
Recurring | Level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 0 | 0
Total financial assets | 0 | 0
Total financial liabilities | 0 | 0
Recurring | Level 3 | Client swap program hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative assets | 0 | 0
Derivative liabilities | 0 | 0
Recurring | Level 3 | Commercial loan fair value hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative liabilities | 0 | 0
Recurring | Level 3 | Mortgage loan fair value hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative assets | 0 |
Derivative liabilities |  |
Recurring | Level 3 | Borrowings cash flow hedges |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Derivative assets | 0 | 0
Recurring | Level 3 | U.S. government and agency securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 0 | 0
Recurring | Level 3 | Asset-backed securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 0 |
Recurring | Level 3 | Municipal bonds |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 0 | 0
Recurring | Level 3 | Corporate debt securities |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | 0 | 0
Recurring | Level 3 | Agency pass-through certificates |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Available-for-sale securities, at fair value | $ 0 | $ 0

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- Definition Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities. + References No definition available. + Details
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