Loans and Allowance for Credit Losses for Loans - Summary of Allocation of Allowance for Loan Losses and Related Loans by Loan Portfolio Segment Disaggregated Based on Allowance Measurement Methodology (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	$ 57,497		$ 74,215
Collectively evaluated for credit losses	490,830		371,865
Total	548,327	$ 519,310	446,080	$ 442,175	$ 436,432	$ 458,655
Individually evaluated for credit losses	286,599		264,678
Collectively evaluated for credit losses	49,068,720		49,945,617
Total	49,355,319		50,210,295
Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	46,015		55,993
Collectively evaluated for credit losses	120,350		77,366
Total	166,365	149,243	133,359	133,988	128,245	139,941
Individually evaluated for credit losses	135,786		96,827
Collectively evaluated for credit losses	9,663,501		9,133,716
Total	9,799,287		9,230,543
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	11,454		17,987
Collectively evaluated for credit losses	297,574		231,611
Total	309,028	301,093	249,598	245,047	239,695	259,408
Individually evaluated for credit losses	130,057		145,419
Collectively evaluated for credit losses	30,272,139		31,824,628
Total	30,402,196		31,970,047
Residential Mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	28		235
Collectively evaluated for credit losses	51,517		42,722
Total	51,545	47,697	42,957	44,621	44,153	39,020
Individually evaluated for credit losses	20,075		21,843
Collectively evaluated for credit losses	5,664,004		5,547,167
Total	5,684,079		5,569,010
Consumer loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	0		0
Collectively evaluated for credit losses	21,389		20,166
Total	21,389	$ 21,277	20,166	$ 18,519	$ 24,339	$ 20,286
Individually evaluated for credit losses	681		589
Collectively evaluated for credit losses	3,469,076		3,440,106
Total	$ 3,469,757		$ 3,440,695