Segment Reporting - Schedule of Segment Reporting Information, by Segment (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2023 USD ($) employee	Dec. 31, 2023 USD ($) employee	Dec. 31, 2022 USD ($) employee	Dec. 31, 2021 USD ($)
Income Statement Related Disclosures
Net interest income		$ 1,816,655	$ 1,796,900	$ 1,532,947
Non-interest revenue		404,010	409,336	450,066
Non-interest expense		1,335,424	1,157,506	1,099,904
Pre-provision net revenue		885,241	1,048,730	883,109
Balance Sheet Related Disclosures
Loans, net of deferred fees and costs	$ 43,404,490	43,404,490	43,716,353
Deposits	$ 50,739,185	$ 50,739,185	$ 48,871,559
Full-time equivalent employees | employee	4,798	4,798	5,027
Operating Segments | Wholesale Banking
Income Statement Related Disclosures
Net interest income		$ 806,399	$ 691,535	558,469
Non-interest revenue		51,918	39,262	34,590
Non-interest expense		159,488	114,212	90,198
Pre-provision net revenue		698,829	616,585	502,861
Balance Sheet Related Disclosures
Loans, net of deferred fees and costs	$ 25,506,870	25,506,870	25,865,667
Deposits	$ 13,847,833	$ 13,847,833	$ 12,942,732
Full-time equivalent employees | employee	334	334	337
Operating Segments | Community Banking
Income Statement Related Disclosures
Net interest income		$ 429,937	$ 412,660	399,261
Non-interest revenue		69,372	50,077	48,301
Non-interest expense		145,275	128,159	114,064
Pre-provision net revenue		354,034	334,578	333,498
Balance Sheet Related Disclosures
Loans, net of deferred fees and costs	$ 7,966,794	7,966,794	8,138,606
Deposits	$ 10,198,357	$ 10,198,357	$ 10,798,409
Full-time equivalent employees | employee	576	576	598
Operating Segments | Consumer Banking
Income Statement Related Disclosures
Net interest income		$ 614,338	$ 465,840	409,439
Non-interest revenue		79,871	86,570	79,725
Non-interest expense		205,674	198,472	177,491
Pre-provision net revenue		488,535	353,938	311,673
Balance Sheet Related Disclosures
Loans, net of deferred fees and costs	$ 2,825,411	2,825,411	2,933,504
Deposits	$ 18,698,298	$ 18,698,298	$ 18,561,521
Full-time equivalent employees | employee	1,522	1,522	1,532
Operating Segments | Financial Management Services
Income Statement Related Disclosures
Net interest income		$ 73,906	$ 69,539	78,647
Non-interest revenue		195,186	182,861	211,002
Non-interest expense		167,612	171,325	184,133
Pre-provision net revenue		101,480	81,075	105,516
Balance Sheet Related Disclosures
Loans, net of deferred fees and costs	$ 5,374,280	5,374,280	5,157,014
Deposits	$ 1,488,090	$ 1,488,090	$ 102,496
Full-time equivalent employees | employee	604	604	768
Treasury and Corporate Other
Income Statement Related Disclosures
Net interest income		$ (107,925)	$ 157,326	87,131
Non-interest revenue		7,663	50,566	76,448
Non-interest expense	$ 51,000	657,375	545,338	534,018
Pre-provision net revenue		(757,637)	(337,446)	$ (370,439)
Balance Sheet Related Disclosures
Loans, net of deferred fees and costs	1,731,135	1,731,135	1,621,562
Deposits	$ 6,506,607	$ 6,506,607	$ 6,466,401
Full-time equivalent employees | employee	1,762	1,762	1,792