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Derivative Instruments and Hedging Activities - Narrative (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023 | Dec. 31, 2023 | Dec. 31, 2022
Derivative [Line Items] |  |  |  |  |  |
Derivative Instruments and Hedges, Assets | $ 194.0 |  | $ 194.0 |  | $ 193.3 |
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease) | 6.0 |  | 6.0 |  | $ 6.7 |
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax | 1.4 | $ 5.9 | 5.8 | $ 3.5 |  |
Interest Income, Hedge Basis Adjustment, Portfolio Layer Method, Increase (Decrease) |  |  | 0.4 |  |  |
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax | (4.6) | (1.5) | (8.1) | (2.0) |  |
Not Designated as Hedging Instrument |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Amount of net fee income recognized in other non-interest income | 0.0 |  | 0.0 |  |  |
Interest Rate Swap |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Derivative Instruments and Hedges, Assets | 850.0 |  | 850.0 |  |  |
Interest Rate Swap | Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax | 5.1 | 23.6 | 22.5 | 14.1 |  |
Interest Rate Collars |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Derivative Instruments and Hedges, Assets | 300.0 |  | 300.0 |  |  |
Interest Rate Swap and Interest Rate Collar |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Derivative Instruments and Hedges, Assets | 1,150.0 |  | 1,150.0 |  |  |
Interest Rate Floor [Member] | Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax | $ (4.6) | $ (1.5) | $ (8.1) | $ (2.0) |  |
three-year forward starting, four-year pay fixed interest rate swap [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Derivative Instruments and Hedges, Assets |  |  |  |  |  | $ 200.0
Hedged Asset, Fair Value Hedge, Cumulative Increase (Decrease) |  |  |  |  |  | $ 8.5

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