Business Segments - Schedule of Operating Results and Other Key Financial Measures for The Individual Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Segment Reporting Information
Net interest income (loss) before provision for (reversal of) credit losses	$ 677,530	$ 572,722	$ 1,894,805	$ 1,691,090
Noninterest income	100,517	84,395	278,797	247,053
Total revenue before provision for (reversal of ) credit losses	778,047	657,117	2,173,602	1,938,143
Provision for (reversal of) credit losses	36,000	42,000	130,000	104,000
Compensation and employee benefits	175,585	135,464	466,861	410,864
Other noninterest expense	101,338	90,336	318,230	297,242
Total noninterest expense	276,923	225,800	785,091	708,106
INCOME BEFORE INCOME TAXES	465,124	389,317	1,258,511	1,126,037
Segment net income	368,394	299,166	968,917	872,471
Loans	55,208,578	52,420,516	54,282,760	52,089,261
Deposits	66,189,767	60,585,256	64,181,406	58,908,960
Segment assets	79,669,531	74,483,720	79,669,531	74,483,720	$ 75,976,475
Consumer and Business Banking
Segment Reporting Information
Net interest income (loss) before provision for (reversal of) credit losses	275,389	290,884	818,195	880,316
Noninterest income	31,191	27,970	91,205	80,288
Total revenue before provision for (reversal of ) credit losses	306,580	318,854	909,400	960,604
Provision for (reversal of) credit losses	16,679	5,927	31,139	5,246
Compensation and employee benefits	60,471	53,865	180,585	161,557
Other noninterest expense	57,695	58,141	172,140	176,279
Total noninterest expense	118,166	112,006	352,725	337,836
INCOME BEFORE INCOME TAXES	171,735	200,921	525,536	617,522
Segment net income	123,347	141,532	374,730	434,992
Loans	20,500,553	19,048,831	20,151,497	18,817,573
Deposits	33,883,506	31,462,739	32,992,699	30,406,431
Segment assets	21,078,748	19,650,183	21,078,748	19,650,183
Commercial Banking
Segment Reporting Information
Net interest income (loss) before provision for (reversal of) credit losses	265,935	288,704	773,080	855,607
Noninterest income	57,983	45,577	161,313	141,634
Total revenue before provision for (reversal of ) credit losses	323,918	334,281	934,393	997,241
Provision for (reversal of) credit losses	35,580	36,934	115,083	99,996
Compensation and employee benefits	62,282	57,582	181,061	175,881
Other noninterest expense	36,413	36,020	114,784	120,371
Total noninterest expense	98,695	93,602	295,845	296,252
INCOME BEFORE INCOME TAXES	189,643	203,745	523,465	600,993
Segment net income	136,267	143,218	373,499	423,407
Loans	34,408,431	32,975,235	33,800,162	32,854,843
Deposits	28,027,523	26,310,972	26,832,722	25,667,059
Segment assets	36,867,668	35,714,691	36,867,668	35,714,691
Treasury and Other
Segment Reporting Information
Net interest income (loss) before provision for (reversal of) credit losses	136,206	(6,866)	303,530	(44,833)
Noninterest income	11,343	10,848	26,279	25,131
Total revenue before provision for (reversal of ) credit losses	147,549	3,982	329,809	(19,702)
Provision for (reversal of) credit losses	(16,259)	(861)	(16,222)	(1,242)
Compensation and employee benefits	52,832	24,017	105,215	73,426
Other noninterest expense	7,230	(3,825)	31,306	592
Total noninterest expense	60,062	20,192	136,521	74,018
INCOME BEFORE INCOME TAXES	103,746	(15,349)	209,510	(92,478)
Segment net income	108,780	14,416	220,688	14,072
Loans	299,594	396,450	331,101	416,845
Deposits	4,278,738	2,811,545	4,355,985	2,835,470
Segment assets	$ 21,723,115	$ 19,118,846	$ 21,723,115	$ 19,118,846