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, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	$ 63,494		$ 86,594
Collectively evaluated for credit losses	378,681		372,061
Total	442,175	$ 436,432	458,655	$ 475,744	$ 468,819	$ 359,202
Individually evaluated for credit losses	243,593		374,093
Collectively evaluated for credit losses	49,853,926		46,543,107
Total	50,097,519		46,917,200
Commercial and industrial
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	54,363		68,745
Collectively evaluated for credit losses	79,625		71,196
Total	133,988	128,245	139,941	154,051	144,539	103,090
Individually evaluated for credit losses	89,898		117,644
Collectively evaluated for credit losses	9,184,732		8,687,186
Total	9,274,630		8,804,830
Commercial Real Estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	9,099		13,174
Collectively evaluated for credit losses	235,948		246,234
Total	245,047	239,695	259,408	267,780	277,227	217,490
Individually evaluated for credit losses	132,508		213,522
Collectively evaluated for credit losses	31,741,811		29,219,346
Total	31,874,319		29,432,868
Residential Mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	32		337
Collectively evaluated for credit losses	44,589		38,683
Total	44,621	44,153	39,020	36,157	29,889	25,120
Individually evaluated for credit losses	20,598		28,869
Collectively evaluated for credit losses	5,542,067		5,335,681
Total	5,562,665		5,364,550
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Individually evaluated for credit losses	0		4,338
Collectively evaluated for credit losses	18,519		15,948
Total	18,519	$ 24,339	20,286	$ 17,756	$ 17,164	$ 13,502
Individually evaluated for credit losses	589		14,058
Collectively evaluated for credit losses	3,385,316		3,300,894
Total	$ 3,385,905		$ 3,314,952