Business Segments - Schedule of Operating Results and Other Key Financial Measures for The Individual Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Segment Reporting Information
Net interest income before provision for (reversal of) credit losses	$ 671,193	$ 600,201
Noninterest income	102,556	92,102
Total revenue before provision for (reversal of) credit losses	773,749	692,303
Provision for (reversal of) credit losses	36,000	49,000
Compensation and employee benefits	172,665	146,435
Other noninterest expense	107,649	105,713
Total noninterest expense	280,314	252,148
INCOME BEFORE INCOME TAXES	457,435	391,155
Segment net income	357,796	290,270
Loans	57,054,649	53,337,711
Deposits	67,547,634	62,637,582
Segment assets	82,886,152	76,165,013	$ 80,434,997
Consumer and Business Banking
Segment Reporting Information
Net interest income before provision for (reversal of) credit losses	269,247	269,733
Noninterest income	39,962	32,285
Total revenue before provision for (reversal of) credit losses	309,209	302,018
Provision for (reversal of) credit losses	9,185	7,685
Compensation and employee benefits	70,096	61,964
Other noninterest expense	62,005	57,192
Total noninterest expense	132,101	119,156
INCOME BEFORE INCOME TAXES	167,923	175,177
Segment net income	120,864	123,088
Loans	21,034,978	19,762,287
Deposits	35,048,413	32,326,906
Segment assets	21,626,337	20,404,813
Commercial Banking
Segment Reporting Information
Net interest income before provision for (reversal of) credit losses	261,286	253,001
Noninterest income	54,331	53,579
Total revenue before provision for (reversal of) credit losses	315,617	306,580
Provision for (reversal of) credit losses	27,007	40,779
Compensation and employee benefits	74,844	61,187
Other noninterest expense	36,470	42,318
Total noninterest expense	111,314	103,505
INCOME BEFORE INCOME TAXES	177,296	162,296
Segment net income	127,639	114,025
Loans	36,019,671	33,211,037
Deposits	28,087,719	26,129,141
Segment assets	38,707,909	35,790,014
Treasury and Other
Segment Reporting Information
Net interest income before provision for (reversal of) credit losses	140,660	77,467
Noninterest income	8,263	6,238
Total revenue before provision for (reversal of) credit losses	148,923	83,705
Provision for (reversal of) credit losses	(192)	536
Compensation and employee benefits	27,725	23,284
Other noninterest expense	9,174	6,203
Total noninterest expense	36,899	29,487
INCOME BEFORE INCOME TAXES	112,216	53,682
Segment net income	109,293	53,157
Loans	0	364,387
Deposits	4,411,502	4,181,535
Segment assets	$ 22,551,906	$ 19,970,186