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v3.24.3

BORROWINGS - Narrative (Details) |  |  | 9 Months Ended | 12 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Dec. 18, 2024 | Nov. 01, 2013 USD ($) investor | Sep. 30, 2024 USD ($) | Sep. 30, 2023 USD ($) | Dec. 31, 2023 USD ($) | Jun. 30, 2024 USD ($) | Mar. 31, 2024 USD ($) | Dec. 18, 2019 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Total available remaining borrowing capacity from FHLB |  |  | $ 762,600,000 |  |  |  |  |
Federal Home Loan Bank advances |  |  | $ 832,629,000 |  | $ 712,852,000 |  |  |
Debt face amount |  | $ 70,000,000 |  |  |  |  |  |
Private debt issuance, number of institutional investors | investor |  | 4 |  |  |  |  |  |
5.00% Senior Notes Due 2028 |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Redemption price (percent) |  | 100.00% |  |  |  |  |  |
Senior Notes |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Fixed interest rate term |  | 10 years |  |  |  |  |  |
U.S. Bank, N.A | Line of Credit |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 2.25% |  |  |  |  |
Outstanding balance on the line of credit |  |  | $ 0 |  |  |  |  |
Line of credit facility, maximum borrowing capacity |  |  | $ 75,000,000 |  |  |  |  |
Line of credit facility, commitment fee percentage |  |  | 0.40% |  |  |  |  |
Putable Advances |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Federal Home Loan Bank advances |  |  | $ 305,000,000 |  |  |  |  |
Minimum |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Interest rate, minimum (as a percent) |  |  | 0.35% |  |  |  |  |
Maximum |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Interest rate, minimum (as a percent) |  |  | 4.94% |  |  |  |  |
Securities Sold Under Repurchase Agreements |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Maximum amount of outstanding agreements |  |  | $ 194,200,000 | $ 241,900,000 |  |  |  |
Total of average agreements |  |  | 138,100,000 | $ 181,200,000 |  |  |  |
Debt outstanding |  |  | 124,894,000 |  |  |  |  |
Subordinated Debentures and Term Loans |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debt outstanding |  |  | 93,562,000 |  | 158,600,000 |  |  |
Subordinated Debenture | 6.75% Subordinated Notes Due 2028 |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debt face amount |  | $ 65,000,000 |  |  |  |  |  |
Interest rate on notes (as a percent) |  | 6.75% |  |  |  |  |  |
Redemption price (percent) |  | 100.00% |  |  |  |  |  |
Issued notice |  |  |  |  |  |  | $ 40,000,000 |
Subordinated Debenture | 6.75% Subordinated Notes Due 2028 | Notice of intent to redeem |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Issued notice |  |  |  |  |  | $ 25,000,000 |  |
Subordinated Debenture | Level One Subordinated Notes |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debt face amount |  |  |  |  |  |  |  | $ 30,000,000
Interest rate on notes (as a percent) |  |  |  |  |  |  |  | 4.75%
Subordinated Debenture | Level One Subordinated Notes | Forecast |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Basis spread on variable rate (as a percent) | 3.11% |  |  |  |  |  |  |
Subordinated Debenture | First Merchant Capital Trust II |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debt face amount |  |  | $ 41,700,000 |  | $ 41,700,000 |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.26161% |  |  |  |  |
Interest rate during the period |  |  | 6.77% |  | 7.21% |  |  |
Subordinated Debenture | Ameriana Capital Trust I |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debt face amount |  |  | $ 10,300,000 |  | $ 10,300,000 |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.26161% |  |  |  |  |
Interest rate during the period |  |  | 6.71% |  | 7.15% |  |  |
Senior Notes | 5.00% Senior Notes Due 2028 |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debt face amount |  | $ 5,000,000 |  |  |  |  |  |
Interest rate on notes (as a percent) |  | 5.00% |  |  |  |  |  |
Secured Debt |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debt outstanding |  |  | $ 7,200,000 |  | $ 7,300,000 |  |  |
Interest rate on notes (as a percent) |  |  | 3.41% |  | 3.41% |  |  |
Secured Debt | Level One |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |
Debt outstanding |  |  | $ 1,200,000 |  | $ 1,200,000 |  |  |
Interest rate on notes (as a percent) |  |  | 1.00% |  | 1.00% |  |  |

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