Derivatives and Hedging Activities - Schedule of Master Netting Arrangements (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross Asset	$ 37.4	$ 45.2
Derivative Asset, Fair Value, Gross Liability	0.0	0.0
Derivative, Collateral, Obligation to Return Securities	0.0	0.0
Derivative, Collateral, Obligation to Return Cash	32.7	45.1
Derivative Asset, Fair Value, Amount Offset Against Collateral, Total	4.7	0.1
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	127.3	159.6
Derivative Liability, Fair Value, Gross Asset	0.0	0.0
Derivative, Collateral, Right to Reclaim Securities	0.0	0.0
Derivative, Collateral, Right to Reclaim Cash	0.0	0.0
Derivative Liability, Fair Value, Amount Offset Against Collateral, Total	127.3	159.6
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral [Abstract]
Securities Sold under Agreements to Repurchase, Gross	782.7	1,052.9
Securities Sold under Agreements to Repurchase, Asset	0.0	0.0
Securities Sold under Agreements to Repurchase, Total	782.7	1,052.9
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	0.0	0.0
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash	782.7	1,052.9
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral, Total	0.0	0.0
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Gross	910.0	1,212.5
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Asset	0.0	0.0
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Total	910.0	1,212.5
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Securities	0.0	0.0
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Cash	782.7	1,052.9
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Amount Offset Against Collateral, Total	127.3	159.6
Derivative Asset, Notional Amount	2,144.7	2,290.7
Derivative Assets, Estimated Fair Value	37.4	45.2
Derivative Liability, Notional Amount	2,295.7	2,449.0
Derivative Liabilities, Estimated Fair Value	127.3	159.6
Collateral Pledged
Offsetting Derivative Liabilities [Abstract]
Derivative, Collateral, Right to Reclaim Securities	0.0
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative, Fair Value, Net	0.0
Interest Rate Swap [Member]
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross Asset	37.3	45.1
Derivative Asset, Fair Value, Gross Liability	0.0	0.0
Derivative, Collateral, Obligation to Return Securities	0.0	0.0
Derivative, Collateral, Obligation to Return Cash	32.7	45.1
Derivative Asset, Fair Value, Amount Offset Against Collateral, Total	4.6	0.0
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	127.1	159.6
Derivative Liability, Fair Value, Gross Asset	0.0	0.0
Derivative, Collateral, Right to Reclaim Securities	0.0	0.0
Derivative, Collateral, Right to Reclaim Cash	0.0	0.0
Derivative Liability, Fair Value, Amount Offset Against Collateral, Total	127.1	159.6
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Assets, Estimated Fair Value	37.3	45.1
Derivative Liabilities, Estimated Fair Value	127.1	159.6
Interest Rate Swap [Member] | Not Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Asset, Notional Amount	1,589.0	1,728.1
Derivative Assets, Estimated Fair Value	34.3	41.6
Derivative Liability, Notional Amount	1,589.0	1,728.1
Derivative Liabilities, Estimated Fair Value	121.1	153.9
Interest Rate Swap [Member] | Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Asset, Notional Amount	550.0	550.0
Derivative Assets, Estimated Fair Value	3.0	3.5
Derivative Liability, Notional Amount	300.0	300.0
Derivative Liabilities, Estimated Fair Value	2.4	0.3
Forward Contracts [Member]
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross Asset		0.1
Derivative Asset, Fair Value, Gross Liability		0.0
Derivative, Collateral, Obligation to Return Securities		0.0
Derivative, Collateral, Obligation to Return Cash		0.0
Derivative Asset, Fair Value, Amount Offset Against Collateral, Total		0.1
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	0.1
Derivative Liability, Fair Value, Gross Asset	0.0
Derivative, Collateral, Right to Reclaim Securities	0.0
Derivative, Collateral, Right to Reclaim Cash	0.0
Derivative Liability, Fair Value, Amount Offset Against Collateral, Total	0.1
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Assets, Estimated Fair Value		0.1
Derivative Liabilities, Estimated Fair Value	0.1
Forward Contracts [Member] | Not Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Asset, Notional Amount	0.0	12.6
Derivative Liability, Notional Amount	5.6	0.0
Derivative Liabilities, Estimated Fair Value	0.1	0.0
Derivative, Fair Value, Net	0.0	0.1
Interest Rate Collars | Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Liability, Notional Amount	300.0	300.0
Derivative Liabilities, Estimated Fair Value	3.6	5.4
Risk Participation Agreements
Offsetting Derivative Liabilities [Abstract]
Derivative Liability, Fair Value, Gross Liability	0.1
Derivative Liability, Fair Value, Gross Asset	0.0
Derivative, Collateral, Right to Reclaim Securities	0.0
Derivative, Collateral, Right to Reclaim Cash	0.0
Derivative Liability, Fair Value, Amount Offset Against Collateral, Total	0.1
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Liabilities, Estimated Fair Value	0.1
Risk Participation Agreements | Not Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Liability, Notional Amount	101.1	106.1
Derivative Liabilities, Estimated Fair Value	0.1	0.0
Interest Rate Lock Commitments [Member]
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross Asset	0.1
Derivative Asset, Fair Value, Gross Liability	0.0
Derivative, Collateral, Obligation to Return Securities	0.0
Derivative, Collateral, Obligation to Return Cash	0.0
Derivative Asset, Fair Value, Amount Offset Against Collateral, Total	0.1
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Assets, Estimated Fair Value	0.1
Interest Rate Lock Commitments [Member] | Not Designated as Hedging Instrument
Offsetting Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned [Abstract]
Derivative Asset, Notional Amount	5.7	0.0
Derivative Assets, Estimated Fair Value	0.1	0.0
Derivative Liability, Notional Amount	0.0	14.8
Derivative Liabilities, Estimated Fair Value	$ 0.0	$ 0.0