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Derivative Instruments and Hedging Activities - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Derivative [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	$ 0.0	$ 3.0	$ 0.4	$ (2.8)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	(0.2)	(3.1)	(1.6)	(11.2)
Not Designated as Hedging Instrument
Derivative [Line Items]
Amount of net fee income recognized in other noninterest income			0.0	0.0
Amount of net gains recognized in mortgage banking revenues			0.0	0.0
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	$ 0.0	$ (12.4)	$ (1.9)	$ 10.1

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Fee Income on Derivatives

+ References

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- Definition

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)
-Publisher FASB
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Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

+ References

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-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
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Amount, before reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 12
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482790/220-10-45-12

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Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482790/220-10-45-11

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