Commitments and Contingencies (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Commitments And Contingencies [Line Items]
Letters of credit outstanding	$ 503,400,000	$ 389,500,000
Mortgage loans sold	2,609,248,000	1,963,214,000	$ 3,146,442,000
Liability for estimated losses on repurchase and indemnification claims	188,000	152,000
Losses charged against liability	60,100	96,000
Unfunded commitments to investment partnerships	94,100,000	54,000,000.0
Commitments to invest in partnership for tax credits	67,000,000.0	36,200,000
Customer balances maintained by clearing broker and subject to indemnification	15,400,000	9,000,000.0
Forward contracts
Commitments And Contingencies [Line Items]
Derivative instrument, contractual amounts	377,500,000	626,900,000
Commercial, commercial real estate, and construction loans | Commitments to extend credit
Commitments And Contingencies [Line Items]
Commitments to fund	11,500,000,000	10,500,000,000
Unused home equity lines | Commitments to extend credit
Commitments And Contingencies [Line Items]
Commitments to fund	999,100,000	845,600,000
Residential real estate | Commitments to extend credit
Commitments And Contingencies [Line Items]
Commitments to fund	$ 361,300,000	$ 222,800,000