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INVESTMENT SECURITIES - Narrative (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022 | Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Trading gain (losses) recorded in servicing income | $ (0.9) | $ (2.6) | $ (1.4) | $ (6.4) |
Tax exempt interest income on available-for-sale securities | $ 2.8 | $ 3.1 | $ 8.4 | $ 8.9 |
Mortgage Backed Securities and Collateralized Mortgage Obligations |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Weighted average yield | 3.09% |  | 3.09% |  | 3.08%
US Treasury Notes Securities | Not Designated as Hedging Instrument, Economic Hedge |  |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |  |
Trading securities | $ 22.0 |  | $ 22.0 |  | $ 19.0

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