Business Segments - Schedule of Operating Results and Other Key Financial Measures for the Individual Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Dec. 31, 2025
Segment Reporting
Net interest income before provision for (reversal of) credit losses	$ 684,651	$ 617,074	$ 1,355,844	$ 1,217,275
Noninterest income	106,492	86,178	209,048	178,280
Total revenue before provision for (reversal of) credit losses	791,143	703,252	1,564,892	1,395,555
Provision for (reversal of) credit losses	33,000	45,000	69,000	94,000
Compensation and employee benefits	172,543	144,841	345,208	291,276
Other noninterest expense	118,079	111,179	225,728	216,892
Total noninterest expense	290,622	256,020	570,936	508,168
INCOME BEFORE INCOME TAXES	467,521	402,232	924,956	793,387
Segment net income	363,700	310,253	721,496	600,523
Loans	58,229,502	54,281,432	57,645,321	53,812,179
Deposits	68,697,645	63,677,832	68,125,815	63,160,581
Segment assets	84,763,472	78,158,067	84,763,472	78,158,067	$ 80,434,997
Consumer and Business Banking
Segment Reporting
Net interest income before provision for (reversal of) credit losses	274,251	273,073	543,498	542,806
Noninterest income	38,205	27,729	78,167	60,014
Total revenue before provision for (reversal of) credit losses	312,456	300,802	621,665	602,820
Provision for (reversal of) credit losses	12,451	6,775	21,636	14,460
Compensation and employee benefits	66,704	58,151	136,800	120,115
Other noninterest expense	61,483	57,252	123,488	114,444
Total noninterest expense	128,187	115,403	260,288	234,559
INCOME BEFORE INCOME TAXES	171,818	178,624	339,741	353,801
Segment net income	123,668	128,295	244,532	251,383
Loans	21,451,804	20,183,539	21,244,542	19,974,077
Deposits	36,143,674	32,750,578	35,599,069	32,539,912
Segment assets	22,179,346	20,735,714	22,179,346	20,735,714
Commercial Banking
Segment Reporting
Net interest income before provision for (reversal of) credit losses	258,824	254,144	520,110	507,145
Noninterest income	55,560	49,751	109,891	103,330
Total revenue before provision for (reversal of) credit losses	314,384	303,895	630,001	610,475
Provision for (reversal of) credit losses	20,549	38,724	47,556	79,503
Compensation and employee benefits	69,778	57,592	144,622	118,779
Other noninterest expense	39,151	36,053	75,621	78,371
Total noninterest expense	108,929	93,645	220,243	197,150
INCOME BEFORE INCOME TAXES	184,906	171,526	362,202	333,822
Segment net income	133,182	123,207	260,821	237,232
Loans	36,777,698	33,767,859	36,400,779	33,490,986
Deposits	28,658,783	26,315,823	28,374,828	26,222,998
Segment assets	38,935,480	36,134,621	38,935,480	36,134,621
Treasury and Other
Segment Reporting
Net interest income before provision for (reversal of) credit losses	151,576	89,857	292,236	167,324
Noninterest income	12,727	8,698	20,990	14,936
Total revenue before provision for (reversal of) credit losses	164,303	98,555	313,226	182,260
Provision for (reversal of) credit losses	0	(499)	(192)	37
Compensation and employee benefits	36,061	29,098	63,786	52,382
Other noninterest expense	17,445	17,874	26,619	24,077
Total noninterest expense	53,506	46,972	90,405	76,459
INCOME BEFORE INCOME TAXES	110,797	52,082	223,013	105,764
Segment net income	106,850	58,751	216,143	111,908
Loans	0	330,034	0	347,116
Deposits	3,895,188	4,611,431	4,151,918	4,397,671
Segment assets	$ 23,648,646	$ 21,287,732	$ 23,648,646	$ 21,287,732