Derivatives and Hedging Activities - Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Derivative [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	$ 0.0	$ 0.1	$ 0.0	$ 0.4
Financial Instruments	0.0		0.0		$ 0.0
Derivative Asset, Notional Amount	1,096.6		1,096.6		1,201.0
Derivative Asset, Estimated Fair Value	29.7		29.7		26.6
Derivative Liability, Notional Amount	1,145.4		1,145.4		1,269.5
Derivative Liabilities, Estimated Fair Value	81.2		81.2		77.3
Collateral Pledged
Derivative [Line Items]
Derivative, Fair Value, Net	0.0		0.0		0.0
Financial Instruments	0.0		0.0		0.0
Not Designated as Hedging Instrument
Derivative [Line Items]
Amount of net fee income recognized in other noninterest income			0.0	0.0
Interest Rate Swap | Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Asset, Notional Amount	1,083.0		1,083.0		1,199.0
Derivative Asset, Estimated Fair Value	29.6		29.6		26.6
Derivative Liability, Notional Amount	1,083.0		1,083.0		1,204.9
Derivative Liabilities, Estimated Fair Value	81.2		81.2		77.3
Risk Participation Agreements | Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Liability, Notional Amount	62.4		62.4		64.6
Derivative Liabilities, Estimated Fair Value	0.0		0.0		0.0
Forward Contracts | Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative, Fair Value, Net	0.0		0.0		0.0
Derivative Asset, Notional Amount	7.0		7.0		1.0
Interest Rate Lock Commitments | Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative Asset, Notional Amount	6.6		6.6		1.0
Derivative Asset, Estimated Fair Value	0.1		0.1		$ 0.0
Cash Flow Hedging [Member] | Interest Rate Swap | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	$ 0.0	$ (0.9)	$ 0.0	$ (1.9)