Loans and Allowance for Credit Losses for Loans - Additional Information (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Feb. 29, 2024	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non covered loans net of unearned discount and deferred loan fees		$ 45,300		$ 45,300	$ 85,400
Accrued interest		208,900		208,900	222,200
Transfer of loans to loans held for sale, net			$ 10,000	1,042,725	10,000	$ 0
Proceeds from sale of commercial premium finance lending division				98,060	0	0
(Losses) gains on sales of loans, net				(5,840)	6,054	6,418
Allowance for credit loss, write-off				1,200	4,200
Net loans		48,240,861		48,240,861	49,764,215
Allowance for loan losses		$ 558,850		$ 558,850	446,080	458,655
Combined loan-to-value ratio home equity loan		80.00%		80.00%
Accrued interest on non-accrual loans				$ 32,500	28,800	21,700
Properties for which formal foreclosure proceedings are in process		$ 4,600		$ 4,600	$ 1,600
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]		Accrued interest receivable		Accrued interest receivable	Accrued interest receivable
Nonperforming financial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Transfer of loans to loans held for sale, net				$ 8,800	$ 10,000
Allowance for credit loss, write-off				1,200	4,200
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Commercial Premium Finance Lending Business
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sale of commercial premium finance lending division	$ 96,800
Disposal group, including discontinued operation, assets	95,500
Disposal group, including discontinued operation, financing receivable	93,600
Disposal group, including discontinued operation, liabilities	$ 2,800
Gain (loss) on disposition of business				3,600
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		$ 304,148		304,148	249,598	259,408
Commercial real estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Transfer of loans to loans held for sale, net				933,000
Financing receivable, sale				151,000
(Losses) gains on sales of loans, net		(13,700)
Commercial real estate | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, sale				79,700
Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		173,002		173,002	133,359	139,941
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses		22,805		22,805	20,166	20,286
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, sale				75,500
Allowance for loan losses		$ 58,895		$ 58,895	$ 42,957	$ 39,020